Dirk M. Elston, MD

To the Editor:

A 56-year-old man with a history of opioid abuse and splenectomy decades prior due to a motor vehicle accident was brought to an outside emergency department with confusion, slurred speech, and difficulty breathing. Over the next few days, he became febrile and hypotensive, requiring vasopressors. Clinical laboratory testing revealed a urine drug screen positive for opioids and a low platelet count in the setting of a rapidly evolving retiform purpuric rash.

The patient was transferred to our institution 6 days after initial presentation with primary diagnoses of septic shock with multiorgan failure and disseminated intravascular coagulation (DIC). Blood cultures were positive for gram-negative rods. After several days of broad-spectrum antibiotics and supportive care, cultures were reported as positive for Capnocytophaga canimorsus. Upon further questioning, the patient’s wife reported that the couple had a new puppy and that the patient often allowed the dog to bite him playfully and lick abrasions on his hands and legs. He had not received medical treatment for any of the dog’s bites.

On initial examination at the time of transfer, the patient’s skin was remarkable for diffuse areas of stellate and retiform purpura with dusky centers and necrosis of the nasal tip and earlobes. Both hands were purpuric, with necrosis of the fingertips (Figure 1A). The flank was marked by large areas of full-thickness sloughing of the skin (Figure 1B). The lower extremities were edematous, with some areas of stellate purpura and numerous large bullae that drained straw-colored fluid (Figure 1C). Lower extremity pulses were found with Doppler ultrasonography.

Given the presence of rapidly developing retiform purpura in the clinical context of severe sepsis, purpura fulminans (PF) was the primary consideration in the differential diagnosis. Levamisole-induced necrosis syndrome also was considered because of necrosis of the ears and nose as well as the history of substance use; however, the patient was not known to have a history of cocaine abuse, and a test of antineutrophil cytoplasmic antibody was negative.

A punch biopsy of the abdomen revealed intravascular thrombi with epidermal and sweat gland necrosis, consistent with PF (Figure 2). Gram, Giemsa, and Gomori methenamine-silver stains were negative for organisms. Tissue culture remained negative. Repeat blood cultures demonstrated Candida parapsilosis fungemia. Respiratory culture was positive for budding yeast.

The patient was treated with antimicrobials, intravenous argatroban, and subcutaneous heparin. Purpura and bullae on the trunk slowly resolved with systemic therapy and wound care with petrolatum and nonadherent dressings. However, lesions on the nasal tip, all fingers of both hands, and several toes evolved into dry gangrene. The hospital course was complicated by renal failure requiring continuous renal replacement therapy; respiratory failure requiring ventilator support; and elevated levels of liver enzymes, consistent with involvement of the hepatic microvasculature.

The patient was in the medical intensive care unit at our institution for 2 weeks and was transferred to a burn center for specialized wound care. At transfer, he was still on a ventilator and receiving continuous renal replacement therapy. Subsequently, the patient required a left above-the-knee amputation, right below-the-knee amputation, and amputation of several digits of the upper extremities. In the months after the amputations, he required multiple stump revisions and experienced surgical site infections that complicated healing.

Purpura fulminans is an uncommon syndrome characterized by intravascular thrombosis and hemorrhagic infarction of the skin. The condition commonly is associated with septic shock, causing vascular collapse and DIC. It often develops rapidly.

Because of associated high mortality, it is important to differentiate PF from other causes of cutaneous retiform purpura, including other causes of thrombosis and large vessel vasculitis. Leading causes of PF include infection and hereditary or acquired deficiency of protein C, protein S, or antithrombin III. Regardless of cause, biopsy results demonstrate vascular thrombosis out of proportion to vasculitis. The mortality rate is 42% to 50%. The incidence of postinfectious sepsis sequelae in PF is higher than in survivors of sepsis only, especially amputation.^1-3 Most patients do not die from complications of sepsis but from sequelae of the hypercoagulable and prothrombotic state associated with PF.⁴ Hemorrhagic infarction can affect the kidneys, brain, lungs, heart, eyes, and adrenal glands (ie, necrosis, namely Waterhouse-Friderichsen syndrome).⁵

The most common infectious cause of PF is sepsis secondary to Neisseria meningitidis, with as many as 25% of infected patients developing PF.⁶Streptococcus pneumoniae is another common cause. Other important causative organisms include Streptococcus pyogenes; Staphylococcus aureus (in the setting of intravenous substance use); Klebsiella oxytoca; Klebsiella aerogenes; rickettsial organisms; and viruses, including cytomegalovirus and varicella-zoster virus.^2,7-13 Two earlier cases associated with Capnocytophaga were characterized by concomitant renal failure, metabolic acidosis, hemolytic anemia, and DIC.¹⁴

It is estimated that Capnocytophaga causes 11% to 46% of all cases of sepsis¹⁵; sepsis resulting from Capnocytophaga has extremely poor outcomes, with mortality reaching as high as 60%. The organism is part of the normal oral flora of cats and dogs, and a bite (less often, a scratch) is the cause of most Capnocytophaga infections. The clinical spectrum of C canimorsus infection associated with dog saliva exposure more commonly includes cellulitis at or around the site of inoculation, meningitis, and endocarditis.¹⁶

Although patients affected by PF can be young and healthy, several risk factors for PF have been identified^2,6,16: asplenia, an immunocompromised state, systemic corticosteroid use, cirrhosis, and alcoholism. Asplenic patients have been shown to be particularly susceptible to systemic Capnocytophaga infection; when bitten by a dog, they should be treated with prophylactic antibiotics to cover Capnocytophaga.¹⁷ Immunocompetent patients rarely develop severe infection with Capnocytophaga.^16,18,19 The complement system in particular is critically important in defending against C canimorsus.²⁰

The underlying pathophysiology of acute infectious PF is multifactorial, encompassing increased expression of procoagulant tissue factor by monocytes and endothelial cells in the presence of bacterial pathogens. Dysfunction of protein C, an anticoagulant component of the coagulation cascade, often is cited as a crucial derangement leading to the development of a prothrombotic state in acute infectious PF.²¹ Serum protein S and antithrombin deficiency also can play a role.²² Specific in vitro examination of C canimorsus has revealed a protease that catalyzes N-terminal cleavage of procoagulant factor X, resulting in loss of function.¹⁵

Retiform purpura is a hallmark feature of PF, often beginning as nonblanching erythema with localized edema and petechiae before evolving into the characteristic stellate lesions with hemorrhagic bullae and subsequent necrosis.²³ Pathologic examination reveals microthrombi involving arterioles and smaller vessels.²⁴ There typically is laboratory evidence of DIC in PF, including elevated prothrombin time and partial thromboplastin time, thrombocytopenia, elevated D-dimer, and a decreased fibrinogen level.^6,23

Capnocytophaga bacteria are challenging to grow on standard culture media. Optimal media for growth include 5% sheep’s blood and chocolate agar.¹⁶ Polymerase chain reaction can identify Capnocytophaga; in cases in which blood culture does not produce growth, 16S ribosomal RNA gene sequencing of tissue from skin biopsy has identified the pathogen.²⁵

Some Capnocytophaga isolates have been shown to produce beta-lactamase; individual strains can be resistant to penicillins, cephalosporins, and imipenem.²⁶ Factors associated with an increased risk for death include decreased leukocyte and platelet counts and an increased level of arterial lactate.²⁷

Empiric antibiotic therapy for Capnocytophaga sepsis should include a beta-lactam and beta-lactamase inhibitor, such as piperacillin-tazobactam. Management of DIC can include therapeutic heparin or low-molecular-weight heparin and prophylactic platelet transfusion to maintain a pre-established value.^28-30 Debridement should be conservative; it is important to wait for definite delineation between viable and necrotic tissue,³¹ which might take several months.³² Human skin allografts, in addition to artificial skin, are utilized as supplemental therapy for more rapid wound closure after removal of necrotic tissue.^33,34 Hyperoxygenated fatty acids have been noted to aid in more rapid wound healing in infants with PF.³⁵

Fresh frozen plasma is one method to replace missing factors, but it contains little protein C.³⁶ Outcomes with recombinant human activated protein C (drotrecogin alfa) are mixed, and studies have shown no benefit in reducing the risk for death.^37,38 Protein C concentrate has shown therapeutic benefit in some case reports and small retrospective studies.⁴ In one case report, protein C concentrate and heparin were utilized in combination with antithrombin III.²¹

Hyperbaric O₂ might be of benefit when initiated within 5 days after onset of PF. However, hyperbaric O₂ does carry risk; O₂ toxicity, barotrauma, and barriers to timely resuscitation when the patient is inside the pressurized chamber can occur.²

There is a single report of successful use of the vasodilator iloprost for meningococcal PF without need for surgical intervention; the team also utilized topical nitroglycerin patches on the fingers to avoid digital amputation.³⁹ Epoprostenol, tissue plasminogen activator, and antithrombin have been utilized in cases of extensive PF. Fibrinolytic therapy might have some utility, but only in a setting of malignancy-associated DIC.⁴⁰

Treatment of acute infectious PF lacks a high level of evidence. Options include replacement of anticoagulant factors, anticoagulant therapy, hyperbaric O₂, topical and systemic vasodilators, and, in the setting of underlying cancer, fibrinolytics. Even with therapy, prognosis is guarded.

To the Editor:

A 56-year-old man with a history of opioid abuse and splenectomy decades prior due to a motor vehicle accident was brought to an outside emergency department with confusion, slurred speech, and difficulty breathing. Over the next few days, he became febrile and hypotensive, requiring vasopressors. Clinical laboratory testing revealed a urine drug screen positive for opioids and a low platelet count in the setting of a rapidly evolving retiform purpuric rash.

The patient was transferred to our institution 6 days after initial presentation with primary diagnoses of septic shock with multiorgan failure and disseminated intravascular coagulation (DIC). Blood cultures were positive for gram-negative rods. After several days of broad-spectrum antibiotics and supportive care, cultures were reported as positive for Capnocytophaga canimorsus. Upon further questioning, the patient’s wife reported that the couple had a new puppy and that the patient often allowed the dog to bite him playfully and lick abrasions on his hands and legs. He had not received medical treatment for any of the dog’s bites.

On initial examination at the time of transfer, the patient’s skin was remarkable for diffuse areas of stellate and retiform purpura with dusky centers and necrosis of the nasal tip and earlobes. Both hands were purpuric, with necrosis of the fingertips (Figure 1A). The flank was marked by large areas of full-thickness sloughing of the skin (Figure 1B). The lower extremities were edematous, with some areas of stellate purpura and numerous large bullae that drained straw-colored fluid (Figure 1C). Lower extremity pulses were found with Doppler ultrasonography.

Given the presence of rapidly developing retiform purpura in the clinical context of severe sepsis, purpura fulminans (PF) was the primary consideration in the differential diagnosis. Levamisole-induced necrosis syndrome also was considered because of necrosis of the ears and nose as well as the history of substance use; however, the patient was not known to have a history of cocaine abuse, and a test of antineutrophil cytoplasmic antibody was negative.

A punch biopsy of the abdomen revealed intravascular thrombi with epidermal and sweat gland necrosis, consistent with PF (Figure 2). Gram, Giemsa, and Gomori methenamine-silver stains were negative for organisms. Tissue culture remained negative. Repeat blood cultures demonstrated Candida parapsilosis fungemia. Respiratory culture was positive for budding yeast.

The patient was treated with antimicrobials, intravenous argatroban, and subcutaneous heparin. Purpura and bullae on the trunk slowly resolved with systemic therapy and wound care with petrolatum and nonadherent dressings. However, lesions on the nasal tip, all fingers of both hands, and several toes evolved into dry gangrene. The hospital course was complicated by renal failure requiring continuous renal replacement therapy; respiratory failure requiring ventilator support; and elevated levels of liver enzymes, consistent with involvement of the hepatic microvasculature.

The patient was in the medical intensive care unit at our institution for 2 weeks and was transferred to a burn center for specialized wound care. At transfer, he was still on a ventilator and receiving continuous renal replacement therapy. Subsequently, the patient required a left above-the-knee amputation, right below-the-knee amputation, and amputation of several digits of the upper extremities. In the months after the amputations, he required multiple stump revisions and experienced surgical site infections that complicated healing.

Purpura fulminans is an uncommon syndrome characterized by intravascular thrombosis and hemorrhagic infarction of the skin. The condition commonly is associated with septic shock, causing vascular collapse and DIC. It often develops rapidly.

Because of associated high mortality, it is important to differentiate PF from other causes of cutaneous retiform purpura, including other causes of thrombosis and large vessel vasculitis. Leading causes of PF include infection and hereditary or acquired deficiency of protein C, protein S, or antithrombin III. Regardless of cause, biopsy results demonstrate vascular thrombosis out of proportion to vasculitis. The mortality rate is 42% to 50%. The incidence of postinfectious sepsis sequelae in PF is higher than in survivors of sepsis only, especially amputation.^1-3 Most patients do not die from complications of sepsis but from sequelae of the hypercoagulable and prothrombotic state associated with PF.⁴ Hemorrhagic infarction can affect the kidneys, brain, lungs, heart, eyes, and adrenal glands (ie, necrosis, namely Waterhouse-Friderichsen syndrome).⁵

The most common infectious cause of PF is sepsis secondary to Neisseria meningitidis, with as many as 25% of infected patients developing PF.⁶Streptococcus pneumoniae is another common cause. Other important causative organisms include Streptococcus pyogenes; Staphylococcus aureus (in the setting of intravenous substance use); Klebsiella oxytoca; Klebsiella aerogenes; rickettsial organisms; and viruses, including cytomegalovirus and varicella-zoster virus.^2,7-13 Two earlier cases associated with Capnocytophaga were characterized by concomitant renal failure, metabolic acidosis, hemolytic anemia, and DIC.¹⁴

It is estimated that Capnocytophaga causes 11% to 46% of all cases of sepsis¹⁵; sepsis resulting from Capnocytophaga has extremely poor outcomes, with mortality reaching as high as 60%. The organism is part of the normal oral flora of cats and dogs, and a bite (less often, a scratch) is the cause of most Capnocytophaga infections. The clinical spectrum of C canimorsus infection associated with dog saliva exposure more commonly includes cellulitis at or around the site of inoculation, meningitis, and endocarditis.¹⁶

Although patients affected by PF can be young and healthy, several risk factors for PF have been identified^2,6,16: asplenia, an immunocompromised state, systemic corticosteroid use, cirrhosis, and alcoholism. Asplenic patients have been shown to be particularly susceptible to systemic Capnocytophaga infection; when bitten by a dog, they should be treated with prophylactic antibiotics to cover Capnocytophaga.¹⁷ Immunocompetent patients rarely develop severe infection with Capnocytophaga.^16,18,19 The complement system in particular is critically important in defending against C canimorsus.²⁰

The underlying pathophysiology of acute infectious PF is multifactorial, encompassing increased expression of procoagulant tissue factor by monocytes and endothelial cells in the presence of bacterial pathogens. Dysfunction of protein C, an anticoagulant component of the coagulation cascade, often is cited as a crucial derangement leading to the development of a prothrombotic state in acute infectious PF.²¹ Serum protein S and antithrombin deficiency also can play a role.²² Specific in vitro examination of C canimorsus has revealed a protease that catalyzes N-terminal cleavage of procoagulant factor X, resulting in loss of function.¹⁵

Retiform purpura is a hallmark feature of PF, often beginning as nonblanching erythema with localized edema and petechiae before evolving into the characteristic stellate lesions with hemorrhagic bullae and subsequent necrosis.²³ Pathologic examination reveals microthrombi involving arterioles and smaller vessels.²⁴ There typically is laboratory evidence of DIC in PF, including elevated prothrombin time and partial thromboplastin time, thrombocytopenia, elevated D-dimer, and a decreased fibrinogen level.^6,23

Capnocytophaga bacteria are challenging to grow on standard culture media. Optimal media for growth include 5% sheep’s blood and chocolate agar.¹⁶ Polymerase chain reaction can identify Capnocytophaga; in cases in which blood culture does not produce growth, 16S ribosomal RNA gene sequencing of tissue from skin biopsy has identified the pathogen.²⁵

Some Capnocytophaga isolates have been shown to produce beta-lactamase; individual strains can be resistant to penicillins, cephalosporins, and imipenem.²⁶ Factors associated with an increased risk for death include decreased leukocyte and platelet counts and an increased level of arterial lactate.²⁷

Empiric antibiotic therapy for Capnocytophaga sepsis should include a beta-lactam and beta-lactamase inhibitor, such as piperacillin-tazobactam. Management of DIC can include therapeutic heparin or low-molecular-weight heparin and prophylactic platelet transfusion to maintain a pre-established value.^28-30 Debridement should be conservative; it is important to wait for definite delineation between viable and necrotic tissue,³¹ which might take several months.³² Human skin allografts, in addition to artificial skin, are utilized as supplemental therapy for more rapid wound closure after removal of necrotic tissue.^33,34 Hyperoxygenated fatty acids have been noted to aid in more rapid wound healing in infants with PF.³⁵

Fresh frozen plasma is one method to replace missing factors, but it contains little protein C.³⁶ Outcomes with recombinant human activated protein C (drotrecogin alfa) are mixed, and studies have shown no benefit in reducing the risk for death.^37,38 Protein C concentrate has shown therapeutic benefit in some case reports and small retrospective studies.⁴ In one case report, protein C concentrate and heparin were utilized in combination with antithrombin III.²¹

Hyperbaric O₂ might be of benefit when initiated within 5 days after onset of PF. However, hyperbaric O₂ does carry risk; O₂ toxicity, barotrauma, and barriers to timely resuscitation when the patient is inside the pressurized chamber can occur.²

There is a single report of successful use of the vasodilator iloprost for meningococcal PF without need for surgical intervention; the team also utilized topical nitroglycerin patches on the fingers to avoid digital amputation.³⁹ Epoprostenol, tissue plasminogen activator, and antithrombin have been utilized in cases of extensive PF. Fibrinolytic therapy might have some utility, but only in a setting of malignancy-associated DIC.⁴⁰

Treatment of acute infectious PF lacks a high level of evidence. Options include replacement of anticoagulant factors, anticoagulant therapy, hyperbaric O₂, topical and systemic vasodilators, and, in the setting of underlying cancer, fibrinolytics. Even with therapy, prognosis is guarded.

To the Editor:

A 56-year-old man with a history of opioid abuse and splenectomy decades prior due to a motor vehicle accident was brought to an outside emergency department with confusion, slurred speech, and difficulty breathing. Over the next few days, he became febrile and hypotensive, requiring vasopressors. Clinical laboratory testing revealed a urine drug screen positive for opioids and a low platelet count in the setting of a rapidly evolving retiform purpuric rash.

The patient was transferred to our institution 6 days after initial presentation with primary diagnoses of septic shock with multiorgan failure and disseminated intravascular coagulation (DIC). Blood cultures were positive for gram-negative rods. After several days of broad-spectrum antibiotics and supportive care, cultures were reported as positive for Capnocytophaga canimorsus. Upon further questioning, the patient’s wife reported that the couple had a new puppy and that the patient often allowed the dog to bite him playfully and lick abrasions on his hands and legs. He had not received medical treatment for any of the dog’s bites.

On initial examination at the time of transfer, the patient’s skin was remarkable for diffuse areas of stellate and retiform purpura with dusky centers and necrosis of the nasal tip and earlobes. Both hands were purpuric, with necrosis of the fingertips (Figure 1A). The flank was marked by large areas of full-thickness sloughing of the skin (Figure 1B). The lower extremities were edematous, with some areas of stellate purpura and numerous large bullae that drained straw-colored fluid (Figure 1C). Lower extremity pulses were found with Doppler ultrasonography.

Given the presence of rapidly developing retiform purpura in the clinical context of severe sepsis, purpura fulminans (PF) was the primary consideration in the differential diagnosis. Levamisole-induced necrosis syndrome also was considered because of necrosis of the ears and nose as well as the history of substance use; however, the patient was not known to have a history of cocaine abuse, and a test of antineutrophil cytoplasmic antibody was negative.

A punch biopsy of the abdomen revealed intravascular thrombi with epidermal and sweat gland necrosis, consistent with PF (Figure 2). Gram, Giemsa, and Gomori methenamine-silver stains were negative for organisms. Tissue culture remained negative. Repeat blood cultures demonstrated Candida parapsilosis fungemia. Respiratory culture was positive for budding yeast.

The patient was treated with antimicrobials, intravenous argatroban, and subcutaneous heparin. Purpura and bullae on the trunk slowly resolved with systemic therapy and wound care with petrolatum and nonadherent dressings. However, lesions on the nasal tip, all fingers of both hands, and several toes evolved into dry gangrene. The hospital course was complicated by renal failure requiring continuous renal replacement therapy; respiratory failure requiring ventilator support; and elevated levels of liver enzymes, consistent with involvement of the hepatic microvasculature.

The patient was in the medical intensive care unit at our institution for 2 weeks and was transferred to a burn center for specialized wound care. At transfer, he was still on a ventilator and receiving continuous renal replacement therapy. Subsequently, the patient required a left above-the-knee amputation, right below-the-knee amputation, and amputation of several digits of the upper extremities. In the months after the amputations, he required multiple stump revisions and experienced surgical site infections that complicated healing.

Purpura fulminans is an uncommon syndrome characterized by intravascular thrombosis and hemorrhagic infarction of the skin. The condition commonly is associated with septic shock, causing vascular collapse and DIC. It often develops rapidly.

Because of associated high mortality, it is important to differentiate PF from other causes of cutaneous retiform purpura, including other causes of thrombosis and large vessel vasculitis. Leading causes of PF include infection and hereditary or acquired deficiency of protein C, protein S, or antithrombin III. Regardless of cause, biopsy results demonstrate vascular thrombosis out of proportion to vasculitis. The mortality rate is 42% to 50%. The incidence of postinfectious sepsis sequelae in PF is higher than in survivors of sepsis only, especially amputation.^1-3 Most patients do not die from complications of sepsis but from sequelae of the hypercoagulable and prothrombotic state associated with PF.⁴ Hemorrhagic infarction can affect the kidneys, brain, lungs, heart, eyes, and adrenal glands (ie, necrosis, namely Waterhouse-Friderichsen syndrome).⁵

The most common infectious cause of PF is sepsis secondary to Neisseria meningitidis, with as many as 25% of infected patients developing PF.⁶Streptococcus pneumoniae is another common cause. Other important causative organisms include Streptococcus pyogenes; Staphylococcus aureus (in the setting of intravenous substance use); Klebsiella oxytoca; Klebsiella aerogenes; rickettsial organisms; and viruses, including cytomegalovirus and varicella-zoster virus.^2,7-13 Two earlier cases associated with Capnocytophaga were characterized by concomitant renal failure, metabolic acidosis, hemolytic anemia, and DIC.¹⁴

It is estimated that Capnocytophaga causes 11% to 46% of all cases of sepsis¹⁵; sepsis resulting from Capnocytophaga has extremely poor outcomes, with mortality reaching as high as 60%. The organism is part of the normal oral flora of cats and dogs, and a bite (less often, a scratch) is the cause of most Capnocytophaga infections. The clinical spectrum of C canimorsus infection associated with dog saliva exposure more commonly includes cellulitis at or around the site of inoculation, meningitis, and endocarditis.¹⁶

Although patients affected by PF can be young and healthy, several risk factors for PF have been identified^2,6,16: asplenia, an immunocompromised state, systemic corticosteroid use, cirrhosis, and alcoholism. Asplenic patients have been shown to be particularly susceptible to systemic Capnocytophaga infection; when bitten by a dog, they should be treated with prophylactic antibiotics to cover Capnocytophaga.¹⁷ Immunocompetent patients rarely develop severe infection with Capnocytophaga.^16,18,19 The complement system in particular is critically important in defending against C canimorsus.²⁰

The underlying pathophysiology of acute infectious PF is multifactorial, encompassing increased expression of procoagulant tissue factor by monocytes and endothelial cells in the presence of bacterial pathogens. Dysfunction of protein C, an anticoagulant component of the coagulation cascade, often is cited as a crucial derangement leading to the development of a prothrombotic state in acute infectious PF.²¹ Serum protein S and antithrombin deficiency also can play a role.²² Specific in vitro examination of C canimorsus has revealed a protease that catalyzes N-terminal cleavage of procoagulant factor X, resulting in loss of function.¹⁵

Retiform purpura is a hallmark feature of PF, often beginning as nonblanching erythema with localized edema and petechiae before evolving into the characteristic stellate lesions with hemorrhagic bullae and subsequent necrosis.²³ Pathologic examination reveals microthrombi involving arterioles and smaller vessels.²⁴ There typically is laboratory evidence of DIC in PF, including elevated prothrombin time and partial thromboplastin time, thrombocytopenia, elevated D-dimer, and a decreased fibrinogen level.^6,23

Capnocytophaga bacteria are challenging to grow on standard culture media. Optimal media for growth include 5% sheep’s blood and chocolate agar.¹⁶ Polymerase chain reaction can identify Capnocytophaga; in cases in which blood culture does not produce growth, 16S ribosomal RNA gene sequencing of tissue from skin biopsy has identified the pathogen.²⁵

Some Capnocytophaga isolates have been shown to produce beta-lactamase; individual strains can be resistant to penicillins, cephalosporins, and imipenem.²⁶ Factors associated with an increased risk for death include decreased leukocyte and platelet counts and an increased level of arterial lactate.²⁷

Empiric antibiotic therapy for Capnocytophaga sepsis should include a beta-lactam and beta-lactamase inhibitor, such as piperacillin-tazobactam. Management of DIC can include therapeutic heparin or low-molecular-weight heparin and prophylactic platelet transfusion to maintain a pre-established value.^28-30 Debridement should be conservative; it is important to wait for definite delineation between viable and necrotic tissue,³¹ which might take several months.³² Human skin allografts, in addition to artificial skin, are utilized as supplemental therapy for more rapid wound closure after removal of necrotic tissue.^33,34 Hyperoxygenated fatty acids have been noted to aid in more rapid wound healing in infants with PF.³⁵

Fresh frozen plasma is one method to replace missing factors, but it contains little protein C.³⁶ Outcomes with recombinant human activated protein C (drotrecogin alfa) are mixed, and studies have shown no benefit in reducing the risk for death.^37,38 Protein C concentrate has shown therapeutic benefit in some case reports and small retrospective studies.⁴ In one case report, protein C concentrate and heparin were utilized in combination with antithrombin III.²¹

Hyperbaric O₂ might be of benefit when initiated within 5 days after onset of PF. However, hyperbaric O₂ does carry risk; O₂ toxicity, barotrauma, and barriers to timely resuscitation when the patient is inside the pressurized chamber can occur.²

There is a single report of successful use of the vasodilator iloprost for meningococcal PF without need for surgical intervention; the team also utilized topical nitroglycerin patches on the fingers to avoid digital amputation.³⁹ Epoprostenol, tissue plasminogen activator, and antithrombin have been utilized in cases of extensive PF. Fibrinolytic therapy might have some utility, but only in a setting of malignancy-associated DIC.⁴⁰

Treatment of acute infectious PF lacks a high level of evidence. Options include replacement of anticoagulant factors, anticoagulant therapy, hyperbaric O₂, topical and systemic vasodilators, and, in the setting of underlying cancer, fibrinolytics. Even with therapy, prognosis is guarded.

Bloodroot (Sanguinaria canadensis) is a member of the family Papaveraceae.¹ This North American plant commonly is found in widespread distribution from Nova Scotia, Canada, to Florida and from the Great Lakes to Mississippi.² Historically, Native Americans used bloodroot as a skin dye and as a medicine for many ailments.³

Bloodroot blooms for only a few days, starting in March, and fruits in June. The flowers comprise 8 to 10 white petals, surrounding a bed of yellow stamens (Figure). The plant thrives in wooded areas and grows to 12 inches tall. In its off-season, the plant remains dormant and can survive below-freezing temperatures.⁴

Chemical Constituents

Bloodroot gets its colloquial name from its red sap, which is released when the plant’s rhizome is cut. This sap contains a high concentration of alkaloids that are used for protection against predators. The rhizome itself has a rusty, red-brown color; the roots are a brighter red-orange.⁴

The rhizome of S canadensis contains the highest concentration of active alkaloids; the roots also contain these chemicals, though to a lesser degree; and the leaves, flowers, and fruits harvest approximately 1% of the alkaloids found in the roots.⁴ The concentration of alkaloids can vary from one plant to the next, depending on environmental conditions.^5,6

The major alkaloids in S canadensis include both quaternary benzophenanthridine alkaloids (eg, sanguinarine, chelerythrine, sanguilutine, chelilutine, sanguirubine, chelirubine) and protopin alkaloids (eg, protopine, allocryptopine).^3,7 Of these, sanguinarine and chelerythrine typically are the most potent.¹ Oral ingestion or topical application of these molecules can have therapeutic and toxic effects.⁸

Biophysiological Effects

Bloodroot has been shown to have remarkable antimicrobial effects.⁹ The plant produces hydrogen peroxide and superoxide anion.¹⁰ These mediators cause oxidative stress, thus inducing destruction of cellular DNA and the cell membrane.¹¹ Although these effects can be helpful when fighting infection, they are not necessarily selective against healthy cells.¹²

Alkaloids of bloodroot also have cardiovascular therapeutic effects. Sanguinarine blocks angiotensin II and causes vasodilation, thus helping treat hypertension.¹³ It also acts as an inotrope by blocking the Na⁺/K⁺ ATPase pump. These effects in a patient who is already taking digoxin can cause notable cardiotoxicity because the 2 drugs share a mechanism of action.¹⁴

 

Chelerythrine blocks production of cyclooxygenase 2 and prostaglandin E₂.¹⁵ This pathway modification results in anti-inflammatory effects that can help treat arthritis, edema, and other inflammatory conditions.¹⁶ Moreover, sanguinarine has demonstrated efficacy in numerous anticancer pathways,¹⁷ including downregulation of intercellular adhesion molecules, vascular cell adhesion molecules, and vascular endothelial growth factor (VEGF).^18-20 Blocking VEGF is one way to inhibit angiogenesis,²¹ which is upregulated in tumor formation, thus sanguinarine can have an antiproliferative anticancer effect.²² Sanguinarine also upregulates molecules such as nuclear factor–κB and the protease enzymes known as caspases to cause proapoptotic effects, furthering its antitumor potential.^23,24

Treatment of Dermatologic Conditions

The initial technique of Mohs micrographic surgery employed a chemopaste that utilized an extract of S canadensis to preserve tissue.²⁵ Outside the dermatologist’s office, bloodroot is used as a topical home remedy for a variety of cutaneous conditions, including cancer, skin tags, and warts.²⁶ Bloodroot is advertised as black salve, an alternative anticancer treatment.^27,28

As useful as this natural agent sounds, it has a pitfall: The alkaloids of S canadensis are nonspecific in their cytotoxicity, damaging neoplastic and healthy tissue.²⁹ This cytotoxic effect can cause escharification through diffuse tissue destruction and has been observed to result in formation of a keloid scar.³⁰ The alkaloids in black salve also have been shown to cause skin erosions and cellular atypia.^28,31 Therefore, the utility of this escharotic in medical treatment is limited.³² Fortuitously, oral antibiotics and wound care can help address this adverse effect.²⁸

Bloodroot was once used as a mouth rinse and toothpaste to treat gingivitis, but this application was later associated with oral leukoplakia, a premalignant condition.³³ Leukoplakia associated with S canadensis extract often is unremitting. Immediate discontinuation of the offending agent produces little regression, suggesting that cellular damage is irreversible.³⁴

Final Thoughts

Although bloodroot demonstrates efficacy as a phytotherapeutic, it does come with notable toxicity. Physicians should warn patients of the unwanted cosmetic effects of black salve, especially oral products that incorporate sanguinarine. Adverse effects on the oropharynx can be irreversible, though the eschar associated with black salve can be treated with a topical or oral corticosteroid.²⁹

Bloodroot (Sanguinaria canadensis) is a member of the family Papaveraceae.¹ This North American plant commonly is found in widespread distribution from Nova Scotia, Canada, to Florida and from the Great Lakes to Mississippi.² Historically, Native Americans used bloodroot as a skin dye and as a medicine for many ailments.³

Bloodroot blooms for only a few days, starting in March, and fruits in June. The flowers comprise 8 to 10 white petals, surrounding a bed of yellow stamens (Figure). The plant thrives in wooded areas and grows to 12 inches tall. In its off-season, the plant remains dormant and can survive below-freezing temperatures.⁴

Chemical Constituents

Bloodroot gets its colloquial name from its red sap, which is released when the plant’s rhizome is cut. This sap contains a high concentration of alkaloids that are used for protection against predators. The rhizome itself has a rusty, red-brown color; the roots are a brighter red-orange.⁴

The rhizome of S canadensis contains the highest concentration of active alkaloids; the roots also contain these chemicals, though to a lesser degree; and the leaves, flowers, and fruits harvest approximately 1% of the alkaloids found in the roots.⁴ The concentration of alkaloids can vary from one plant to the next, depending on environmental conditions.^5,6

The major alkaloids in S canadensis include both quaternary benzophenanthridine alkaloids (eg, sanguinarine, chelerythrine, sanguilutine, chelilutine, sanguirubine, chelirubine) and protopin alkaloids (eg, protopine, allocryptopine).^3,7 Of these, sanguinarine and chelerythrine typically are the most potent.¹ Oral ingestion or topical application of these molecules can have therapeutic and toxic effects.⁸

Biophysiological Effects

Bloodroot has been shown to have remarkable antimicrobial effects.⁹ The plant produces hydrogen peroxide and superoxide anion.¹⁰ These mediators cause oxidative stress, thus inducing destruction of cellular DNA and the cell membrane.¹¹ Although these effects can be helpful when fighting infection, they are not necessarily selective against healthy cells.¹²

Alkaloids of bloodroot also have cardiovascular therapeutic effects. Sanguinarine blocks angiotensin II and causes vasodilation, thus helping treat hypertension.¹³ It also acts as an inotrope by blocking the Na⁺/K⁺ ATPase pump. These effects in a patient who is already taking digoxin can cause notable cardiotoxicity because the 2 drugs share a mechanism of action.¹⁴

 

Chelerythrine blocks production of cyclooxygenase 2 and prostaglandin E₂.¹⁵ This pathway modification results in anti-inflammatory effects that can help treat arthritis, edema, and other inflammatory conditions.¹⁶ Moreover, sanguinarine has demonstrated efficacy in numerous anticancer pathways,¹⁷ including downregulation of intercellular adhesion molecules, vascular cell adhesion molecules, and vascular endothelial growth factor (VEGF).^18-20 Blocking VEGF is one way to inhibit angiogenesis,²¹ which is upregulated in tumor formation, thus sanguinarine can have an antiproliferative anticancer effect.²² Sanguinarine also upregulates molecules such as nuclear factor–κB and the protease enzymes known as caspases to cause proapoptotic effects, furthering its antitumor potential.^23,24

Treatment of Dermatologic Conditions

The initial technique of Mohs micrographic surgery employed a chemopaste that utilized an extract of S canadensis to preserve tissue.²⁵ Outside the dermatologist’s office, bloodroot is used as a topical home remedy for a variety of cutaneous conditions, including cancer, skin tags, and warts.²⁶ Bloodroot is advertised as black salve, an alternative anticancer treatment.^27,28

As useful as this natural agent sounds, it has a pitfall: The alkaloids of S canadensis are nonspecific in their cytotoxicity, damaging neoplastic and healthy tissue.²⁹ This cytotoxic effect can cause escharification through diffuse tissue destruction and has been observed to result in formation of a keloid scar.³⁰ The alkaloids in black salve also have been shown to cause skin erosions and cellular atypia.^28,31 Therefore, the utility of this escharotic in medical treatment is limited.³² Fortuitously, oral antibiotics and wound care can help address this adverse effect.²⁸

Bloodroot was once used as a mouth rinse and toothpaste to treat gingivitis, but this application was later associated with oral leukoplakia, a premalignant condition.³³ Leukoplakia associated with S canadensis extract often is unremitting. Immediate discontinuation of the offending agent produces little regression, suggesting that cellular damage is irreversible.³⁴

Final Thoughts

Although bloodroot demonstrates efficacy as a phytotherapeutic, it does come with notable toxicity. Physicians should warn patients of the unwanted cosmetic effects of black salve, especially oral products that incorporate sanguinarine. Adverse effects on the oropharynx can be irreversible, though the eschar associated with black salve can be treated with a topical or oral corticosteroid.²⁹

Bloodroot (Sanguinaria canadensis) is a member of the family Papaveraceae.¹ This North American plant commonly is found in widespread distribution from Nova Scotia, Canada, to Florida and from the Great Lakes to Mississippi.² Historically, Native Americans used bloodroot as a skin dye and as a medicine for many ailments.³

Bloodroot blooms for only a few days, starting in March, and fruits in June. The flowers comprise 8 to 10 white petals, surrounding a bed of yellow stamens (Figure). The plant thrives in wooded areas and grows to 12 inches tall. In its off-season, the plant remains dormant and can survive below-freezing temperatures.⁴

Chemical Constituents

Bloodroot gets its colloquial name from its red sap, which is released when the plant’s rhizome is cut. This sap contains a high concentration of alkaloids that are used for protection against predators. The rhizome itself has a rusty, red-brown color; the roots are a brighter red-orange.⁴

The rhizome of S canadensis contains the highest concentration of active alkaloids; the roots also contain these chemicals, though to a lesser degree; and the leaves, flowers, and fruits harvest approximately 1% of the alkaloids found in the roots.⁴ The concentration of alkaloids can vary from one plant to the next, depending on environmental conditions.^5,6

The major alkaloids in S canadensis include both quaternary benzophenanthridine alkaloids (eg, sanguinarine, chelerythrine, sanguilutine, chelilutine, sanguirubine, chelirubine) and protopin alkaloids (eg, protopine, allocryptopine).^3,7 Of these, sanguinarine and chelerythrine typically are the most potent.¹ Oral ingestion or topical application of these molecules can have therapeutic and toxic effects.⁸

Biophysiological Effects

Bloodroot has been shown to have remarkable antimicrobial effects.⁹ The plant produces hydrogen peroxide and superoxide anion.¹⁰ These mediators cause oxidative stress, thus inducing destruction of cellular DNA and the cell membrane.¹¹ Although these effects can be helpful when fighting infection, they are not necessarily selective against healthy cells.¹²

Alkaloids of bloodroot also have cardiovascular therapeutic effects. Sanguinarine blocks angiotensin II and causes vasodilation, thus helping treat hypertension.¹³ It also acts as an inotrope by blocking the Na⁺/K⁺ ATPase pump. These effects in a patient who is already taking digoxin can cause notable cardiotoxicity because the 2 drugs share a mechanism of action.¹⁴

 

Chelerythrine blocks production of cyclooxygenase 2 and prostaglandin E₂.¹⁵ This pathway modification results in anti-inflammatory effects that can help treat arthritis, edema, and other inflammatory conditions.¹⁶ Moreover, sanguinarine has demonstrated efficacy in numerous anticancer pathways,¹⁷ including downregulation of intercellular adhesion molecules, vascular cell adhesion molecules, and vascular endothelial growth factor (VEGF).^18-20 Blocking VEGF is one way to inhibit angiogenesis,²¹ which is upregulated in tumor formation, thus sanguinarine can have an antiproliferative anticancer effect.²² Sanguinarine also upregulates molecules such as nuclear factor–κB and the protease enzymes known as caspases to cause proapoptotic effects, furthering its antitumor potential.^23,24

Treatment of Dermatologic Conditions

The initial technique of Mohs micrographic surgery employed a chemopaste that utilized an extract of S canadensis to preserve tissue.²⁵ Outside the dermatologist’s office, bloodroot is used as a topical home remedy for a variety of cutaneous conditions, including cancer, skin tags, and warts.²⁶ Bloodroot is advertised as black salve, an alternative anticancer treatment.^27,28

As useful as this natural agent sounds, it has a pitfall: The alkaloids of S canadensis are nonspecific in their cytotoxicity, damaging neoplastic and healthy tissue.²⁹ This cytotoxic effect can cause escharification through diffuse tissue destruction and has been observed to result in formation of a keloid scar.³⁰ The alkaloids in black salve also have been shown to cause skin erosions and cellular atypia.^28,31 Therefore, the utility of this escharotic in medical treatment is limited.³² Fortuitously, oral antibiotics and wound care can help address this adverse effect.²⁸

Bloodroot was once used as a mouth rinse and toothpaste to treat gingivitis, but this application was later associated with oral leukoplakia, a premalignant condition.³³ Leukoplakia associated with S canadensis extract often is unremitting. Immediate discontinuation of the offending agent produces little regression, suggesting that cellular damage is irreversible.³⁴

Final Thoughts

Although bloodroot demonstrates efficacy as a phytotherapeutic, it does come with notable toxicity. Physicians should warn patients of the unwanted cosmetic effects of black salve, especially oral products that incorporate sanguinarine. Adverse effects on the oropharynx can be irreversible, though the eschar associated with black salve can be treated with a topical or oral corticosteroid.²⁹

Sea cucumbers—commonly known as trepang in Indonesia, namako in Japan, and hai shen in China, where they are treasured as a food delicacy—are sea creatures belonging to the phylum Echinodermata, class Holothuridea, and family Cucumariidae . ^1,2 They are an integral part of a variety of marine habitats, serving as cleaners as they filter through sediment for nutrients. They can be found on the ocean floor under hundreds of feet of water or in shallow sandy waters along the coast, but they most commonly are found living among coral reefs. Sea cucumbers look just as they sound—shaped like cucumbers or sausages, ranging from under 1 inch to upwards of 6 feet in length depending on the specific species (Figure 1). They have a group of tentacles around the mouth used for filtering sediment, and they move about the ocean floor on tubular feet protruding through the body wall, similar to a sea star.

Beneficial Properties and Cultural Relevance

Although more than 1200 species of sea cucumbers have been identified thus far, only about 20 of these are edible.² The most common of the edible species is Stichopus japonicus, which can be found off the coasts of Korea, China, Japan, and Russia. This particular species most commonly is used in traditional dishes and is divided into 3 groups based on the color: red, green, or black. The price and taste of sea cucumbers varies based on the color, with red being the most expensive.² The body wall of the sea cucumber is cleaned, repeatedly boiled, and dried until edible. It is considered a delicacy, not only in food but also in pharmaceutical forms, as it is comprised of a variety of vitamins, minerals, and other nutrients that are thought to provide anticancer, anticoagulant, antioxidant, antifungal, and anti-inflammatory properties. Components of the body wall include collagen, mucopolysaccharides, peptides, gelatin, glycosaminoglycans, glycosides (including various holotoxins), hydroxylates, saponins, and fatty acids.² The regenerative properties of the sea cucumber also are important in future biomedical developments.

Toxic Properties

Although sea cucumbers have proven to have many beneficial properties, at least 30 species also produce potent toxins that pose a danger to both humans and other wildlife.³ The toxins are collectively referred to as holothurin; however, specific species actually produce a variety of holothurin toxins with unique chemical structures. Each toxin is a variation of a specific triterpene glycoside called saponins, which are common glycosides in the plant world. Holothurin was the first saponin to be found in animals. The only animals known to contain holothurin are the echinoderms, including sea cucumbers and sea stars.¹ Holothurins A and B are the 2 groups of holothurin toxins produced specifically by sea cucumbers. The toxins are composed of roughly 60% glycosides and pigment; 30% free amino acids (alanine, arginine, cysteine, glycine, glutamic acid, histidine, serine, and valine); 5% to 10% insoluble proteins; and 1% cholesterol, salts, and polypeptides.³

Holothurins are concentrated in granules within specialized structures of the sea cucumber called Cuvierian tubules, which freely float in the posterior coelomic cavity of the sea cucumber and are attached at the base of the respiratory tree. It is with these tubules that sea cucumbers utilize a unique defensive mechanism. Upon disturbance, the sea cucumber will turn its posterior end to the threat and squeeze its body in a series of violent contractions, inducing a tear in the cloacal wall.⁴ The tubules pass through this tear, are autotomized from the attachment point at the respiratory tree, and are finally expelled through the anus onto the predator and into the surrounding waters. The tubules are both sticky on contact and poisonous due to the holothurin, allowing the sea cucumber to crawl away from the threat unscathed. Over time, the tubules will regenerate, allowing the sea cucumber to protect itself again in the face of future danger.

Aside from direct disturbance by a threat, sea cucumbers also are known to undergo evisceration due to high temperatures and oxygen deficiency.³ Species that lack Cuvierian tubules can still produce holothurin toxins, though the toxins are secreted onto the outer surface of the body wall and mainly pose a risk with direct contact undiluted by seawater.⁵ The toxin induces a neural blockade in other sea creatures through its interaction with ion channels. On Asian islands, sea cucumbers have been exploited for this ability and commonly are thrown into tidal pools by fishermen to paralyze fish for easier capture.¹

Effects on Human Skin

In humans, the holothurin toxins of sea cucumbers cause an acute irritant dermatitis upon contact with the skin.⁶ Fishermen or divers handling sea cucumbers without gloves may present with an irritant contact dermatitis characterized by marked erythema and swelling (Figure 2).^6-8 Additionally, holothurin toxins can cause irritation of the mucous membranes of the eyes and mouth. Contact with the mucous membranes of the eyes can induce a painful conjunctivitis that may result in blindness.^6,8 Ingestion of large quantities of sea cucumber can produce an anticoagulant effect, and toxins in some species act similar to cardiac glycosides.^3,9

 

In addition to their own toxins, sea cucumbers also can secrete undigested nematocysts of previously consumed cnidarians through the integument.^7,10 In this case, the result of direct contact with the body wall is similar to a jellyfish sting in addition to the irritant contact dermatitis caused by the holothurin toxin.

Treatment and Prevention

Irritant dermatitis resulting from contact with a holothurin toxin is first treated with cleansing of the affected area at the time of exposure with generous amounts of seawater or preferably hot seawater and soap. Most marine toxins are inactivated by heat, but holothurin is partially heat stable. Vinegar or isopropyl alcohol also have been used.⁹ The result is removal of the slime containing the holothurin toxin rather than deactivation of the toxin. Although this alone may relieve symptoms, dermatitis also may be addressed with topical anesthetics, corticosteroids, or, if a severe reaction has occurred, systemic steroids.⁹

Conjunctivitis should be addressed with copious irrigation with tap water and topical anesthesia. Following proper irrigation, providers may choose to follow up with fluorescein staining to rule out corneal injury.¹⁰

The dermatologic effects of holothurin toxins can be prevented with the use of gloves and diving masks or goggles. Proper protective wear should be utilized not only when directly handling sea cucumbers but also when swimming in water where sea cucumbers may be present. Systemic toxicity can be prevented by proper cooking, as holothurin toxins are only partially heat resistant and also are hydrolyzed into nontoxic products by gastric acid. Additionally, the species of the sea cucumber should be confirmed prior to consumption, as edible species are known to contain less toxin.¹

Conclusion

Although sea cucumbers have ecologic, culinary, and pharmaceutical value, they also can pose a threat to both humans and wildlife. The holothurin toxins produced by sea cucumbers cause a painful contact dermatitis and can lead to conjunctivitis and even blindness following eye exposure. Although the toxin is broken down into nontoxic metabolites by gastric acid, large amounts of potent variants can induce systemic effects. Individuals who come in contact with sea cucumbers, such as fishermen and divers, should utilize proper protection including gloves and protective eyewear.

Sea cucumbers—commonly known as trepang in Indonesia, namako in Japan, and hai shen in China, where they are treasured as a food delicacy—are sea creatures belonging to the phylum Echinodermata, class Holothuridea, and family Cucumariidae . ^1,2 They are an integral part of a variety of marine habitats, serving as cleaners as they filter through sediment for nutrients. They can be found on the ocean floor under hundreds of feet of water or in shallow sandy waters along the coast, but they most commonly are found living among coral reefs. Sea cucumbers look just as they sound—shaped like cucumbers or sausages, ranging from under 1 inch to upwards of 6 feet in length depending on the specific species (Figure 1). They have a group of tentacles around the mouth used for filtering sediment, and they move about the ocean floor on tubular feet protruding through the body wall, similar to a sea star.

Beneficial Properties and Cultural Relevance

Although more than 1200 species of sea cucumbers have been identified thus far, only about 20 of these are edible.² The most common of the edible species is Stichopus japonicus, which can be found off the coasts of Korea, China, Japan, and Russia. This particular species most commonly is used in traditional dishes and is divided into 3 groups based on the color: red, green, or black. The price and taste of sea cucumbers varies based on the color, with red being the most expensive.² The body wall of the sea cucumber is cleaned, repeatedly boiled, and dried until edible. It is considered a delicacy, not only in food but also in pharmaceutical forms, as it is comprised of a variety of vitamins, minerals, and other nutrients that are thought to provide anticancer, anticoagulant, antioxidant, antifungal, and anti-inflammatory properties. Components of the body wall include collagen, mucopolysaccharides, peptides, gelatin, glycosaminoglycans, glycosides (including various holotoxins), hydroxylates, saponins, and fatty acids.² The regenerative properties of the sea cucumber also are important in future biomedical developments.

Toxic Properties

Although sea cucumbers have proven to have many beneficial properties, at least 30 species also produce potent toxins that pose a danger to both humans and other wildlife.³ The toxins are collectively referred to as holothurin; however, specific species actually produce a variety of holothurin toxins with unique chemical structures. Each toxin is a variation of a specific triterpene glycoside called saponins, which are common glycosides in the plant world. Holothurin was the first saponin to be found in animals. The only animals known to contain holothurin are the echinoderms, including sea cucumbers and sea stars.¹ Holothurins A and B are the 2 groups of holothurin toxins produced specifically by sea cucumbers. The toxins are composed of roughly 60% glycosides and pigment; 30% free amino acids (alanine, arginine, cysteine, glycine, glutamic acid, histidine, serine, and valine); 5% to 10% insoluble proteins; and 1% cholesterol, salts, and polypeptides.³

Holothurins are concentrated in granules within specialized structures of the sea cucumber called Cuvierian tubules, which freely float in the posterior coelomic cavity of the sea cucumber and are attached at the base of the respiratory tree. It is with these tubules that sea cucumbers utilize a unique defensive mechanism. Upon disturbance, the sea cucumber will turn its posterior end to the threat and squeeze its body in a series of violent contractions, inducing a tear in the cloacal wall.⁴ The tubules pass through this tear, are autotomized from the attachment point at the respiratory tree, and are finally expelled through the anus onto the predator and into the surrounding waters. The tubules are both sticky on contact and poisonous due to the holothurin, allowing the sea cucumber to crawl away from the threat unscathed. Over time, the tubules will regenerate, allowing the sea cucumber to protect itself again in the face of future danger.

Aside from direct disturbance by a threat, sea cucumbers also are known to undergo evisceration due to high temperatures and oxygen deficiency.³ Species that lack Cuvierian tubules can still produce holothurin toxins, though the toxins are secreted onto the outer surface of the body wall and mainly pose a risk with direct contact undiluted by seawater.⁵ The toxin induces a neural blockade in other sea creatures through its interaction with ion channels. On Asian islands, sea cucumbers have been exploited for this ability and commonly are thrown into tidal pools by fishermen to paralyze fish for easier capture.¹

Effects on Human Skin

In humans, the holothurin toxins of sea cucumbers cause an acute irritant dermatitis upon contact with the skin.⁶ Fishermen or divers handling sea cucumbers without gloves may present with an irritant contact dermatitis characterized by marked erythema and swelling (Figure 2).^6-8 Additionally, holothurin toxins can cause irritation of the mucous membranes of the eyes and mouth. Contact with the mucous membranes of the eyes can induce a painful conjunctivitis that may result in blindness.^6,8 Ingestion of large quantities of sea cucumber can produce an anticoagulant effect, and toxins in some species act similar to cardiac glycosides.^3,9

 

In addition to their own toxins, sea cucumbers also can secrete undigested nematocysts of previously consumed cnidarians through the integument.^7,10 In this case, the result of direct contact with the body wall is similar to a jellyfish sting in addition to the irritant contact dermatitis caused by the holothurin toxin.

Treatment and Prevention

Irritant dermatitis resulting from contact with a holothurin toxin is first treated with cleansing of the affected area at the time of exposure with generous amounts of seawater or preferably hot seawater and soap. Most marine toxins are inactivated by heat, but holothurin is partially heat stable. Vinegar or isopropyl alcohol also have been used.⁹ The result is removal of the slime containing the holothurin toxin rather than deactivation of the toxin. Although this alone may relieve symptoms, dermatitis also may be addressed with topical anesthetics, corticosteroids, or, if a severe reaction has occurred, systemic steroids.⁹

Conjunctivitis should be addressed with copious irrigation with tap water and topical anesthesia. Following proper irrigation, providers may choose to follow up with fluorescein staining to rule out corneal injury.¹⁰

The dermatologic effects of holothurin toxins can be prevented with the use of gloves and diving masks or goggles. Proper protective wear should be utilized not only when directly handling sea cucumbers but also when swimming in water where sea cucumbers may be present. Systemic toxicity can be prevented by proper cooking, as holothurin toxins are only partially heat resistant and also are hydrolyzed into nontoxic products by gastric acid. Additionally, the species of the sea cucumber should be confirmed prior to consumption, as edible species are known to contain less toxin.¹

Conclusion

Although sea cucumbers have ecologic, culinary, and pharmaceutical value, they also can pose a threat to both humans and wildlife. The holothurin toxins produced by sea cucumbers cause a painful contact dermatitis and can lead to conjunctivitis and even blindness following eye exposure. Although the toxin is broken down into nontoxic metabolites by gastric acid, large amounts of potent variants can induce systemic effects. Individuals who come in contact with sea cucumbers, such as fishermen and divers, should utilize proper protection including gloves and protective eyewear.

Sea cucumbers—commonly known as trepang in Indonesia, namako in Japan, and hai shen in China, where they are treasured as a food delicacy—are sea creatures belonging to the phylum Echinodermata, class Holothuridea, and family Cucumariidae . ^1,2 They are an integral part of a variety of marine habitats, serving as cleaners as they filter through sediment for nutrients. They can be found on the ocean floor under hundreds of feet of water or in shallow sandy waters along the coast, but they most commonly are found living among coral reefs. Sea cucumbers look just as they sound—shaped like cucumbers or sausages, ranging from under 1 inch to upwards of 6 feet in length depending on the specific species (Figure 1). They have a group of tentacles around the mouth used for filtering sediment, and they move about the ocean floor on tubular feet protruding through the body wall, similar to a sea star.

Beneficial Properties and Cultural Relevance

Although more than 1200 species of sea cucumbers have been identified thus far, only about 20 of these are edible.² The most common of the edible species is Stichopus japonicus, which can be found off the coasts of Korea, China, Japan, and Russia. This particular species most commonly is used in traditional dishes and is divided into 3 groups based on the color: red, green, or black. The price and taste of sea cucumbers varies based on the color, with red being the most expensive.² The body wall of the sea cucumber is cleaned, repeatedly boiled, and dried until edible. It is considered a delicacy, not only in food but also in pharmaceutical forms, as it is comprised of a variety of vitamins, minerals, and other nutrients that are thought to provide anticancer, anticoagulant, antioxidant, antifungal, and anti-inflammatory properties. Components of the body wall include collagen, mucopolysaccharides, peptides, gelatin, glycosaminoglycans, glycosides (including various holotoxins), hydroxylates, saponins, and fatty acids.² The regenerative properties of the sea cucumber also are important in future biomedical developments.

Toxic Properties

Although sea cucumbers have proven to have many beneficial properties, at least 30 species also produce potent toxins that pose a danger to both humans and other wildlife.³ The toxins are collectively referred to as holothurin; however, specific species actually produce a variety of holothurin toxins with unique chemical structures. Each toxin is a variation of a specific triterpene glycoside called saponins, which are common glycosides in the plant world. Holothurin was the first saponin to be found in animals. The only animals known to contain holothurin are the echinoderms, including sea cucumbers and sea stars.¹ Holothurins A and B are the 2 groups of holothurin toxins produced specifically by sea cucumbers. The toxins are composed of roughly 60% glycosides and pigment; 30% free amino acids (alanine, arginine, cysteine, glycine, glutamic acid, histidine, serine, and valine); 5% to 10% insoluble proteins; and 1% cholesterol, salts, and polypeptides.³

Holothurins are concentrated in granules within specialized structures of the sea cucumber called Cuvierian tubules, which freely float in the posterior coelomic cavity of the sea cucumber and are attached at the base of the respiratory tree. It is with these tubules that sea cucumbers utilize a unique defensive mechanism. Upon disturbance, the sea cucumber will turn its posterior end to the threat and squeeze its body in a series of violent contractions, inducing a tear in the cloacal wall.⁴ The tubules pass through this tear, are autotomized from the attachment point at the respiratory tree, and are finally expelled through the anus onto the predator and into the surrounding waters. The tubules are both sticky on contact and poisonous due to the holothurin, allowing the sea cucumber to crawl away from the threat unscathed. Over time, the tubules will regenerate, allowing the sea cucumber to protect itself again in the face of future danger.

Aside from direct disturbance by a threat, sea cucumbers also are known to undergo evisceration due to high temperatures and oxygen deficiency.³ Species that lack Cuvierian tubules can still produce holothurin toxins, though the toxins are secreted onto the outer surface of the body wall and mainly pose a risk with direct contact undiluted by seawater.⁵ The toxin induces a neural blockade in other sea creatures through its interaction with ion channels. On Asian islands, sea cucumbers have been exploited for this ability and commonly are thrown into tidal pools by fishermen to paralyze fish for easier capture.¹

Effects on Human Skin

In humans, the holothurin toxins of sea cucumbers cause an acute irritant dermatitis upon contact with the skin.⁶ Fishermen or divers handling sea cucumbers without gloves may present with an irritant contact dermatitis characterized by marked erythema and swelling (Figure 2).^6-8 Additionally, holothurin toxins can cause irritation of the mucous membranes of the eyes and mouth. Contact with the mucous membranes of the eyes can induce a painful conjunctivitis that may result in blindness.^6,8 Ingestion of large quantities of sea cucumber can produce an anticoagulant effect, and toxins in some species act similar to cardiac glycosides.^3,9

 

In addition to their own toxins, sea cucumbers also can secrete undigested nematocysts of previously consumed cnidarians through the integument.^7,10 In this case, the result of direct contact with the body wall is similar to a jellyfish sting in addition to the irritant contact dermatitis caused by the holothurin toxin.

Treatment and Prevention

Irritant dermatitis resulting from contact with a holothurin toxin is first treated with cleansing of the affected area at the time of exposure with generous amounts of seawater or preferably hot seawater and soap. Most marine toxins are inactivated by heat, but holothurin is partially heat stable. Vinegar or isopropyl alcohol also have been used.⁹ The result is removal of the slime containing the holothurin toxin rather than deactivation of the toxin. Although this alone may relieve symptoms, dermatitis also may be addressed with topical anesthetics, corticosteroids, or, if a severe reaction has occurred, systemic steroids.⁹

Conjunctivitis should be addressed with copious irrigation with tap water and topical anesthesia. Following proper irrigation, providers may choose to follow up with fluorescein staining to rule out corneal injury.¹⁰

The dermatologic effects of holothurin toxins can be prevented with the use of gloves and diving masks or goggles. Proper protective wear should be utilized not only when directly handling sea cucumbers but also when swimming in water where sea cucumbers may be present. Systemic toxicity can be prevented by proper cooking, as holothurin toxins are only partially heat resistant and also are hydrolyzed into nontoxic products by gastric acid. Additionally, the species of the sea cucumber should be confirmed prior to consumption, as edible species are known to contain less toxin.¹

Conclusion

Although sea cucumbers have ecologic, culinary, and pharmaceutical value, they also can pose a threat to both humans and wildlife. The holothurin toxins produced by sea cucumbers cause a painful contact dermatitis and can lead to conjunctivitis and even blindness following eye exposure. Although the toxin is broken down into nontoxic metabolites by gastric acid, large amounts of potent variants can induce systemic effects. Individuals who come in contact with sea cucumbers, such as fishermen and divers, should utilize proper protection including gloves and protective eyewear.

 

To the Editor:

Phacomatosis pigmentokeratotica (PPK) is a rare epidermal nevus syndrome complicated by multiple extracutaneous anomalies, including skeletal defects and neurologic anomalies. Less common associations include lateral curvature of the spine and hyperhidrosis. We present a patient with PPK and unilateral Raynaud phenomenon in addition to a segmental distribution of melanocytic nevi, hyperhidrosis, and scoliosis.

A 9-year-old girl was born with a yellow-orange alopecic plaque on the right side of the scalp (Figure 1). There also were 2 large, irregularly pigmented patches localized on the right side of the upper back and buttock. Over 3 years, numerous papular nevi developed within these pigmented patches and were diagnosed as speckled lentiginous nevi (Figure 2). In addition, numerous nevi of various sizes affected the right face, right shoulder, right arm (Figure 3), and right neck and were clearly demarcated along the midline. Several nevi also were noted within the nevus sebaceous on the right scalp. These skin lesions expanded progressively with age. At 6 years of age, she was diagnosed with hyperhidrosis of the right half of the body, which was most pronounced on the face. Raynaud phenomenon restricted to the right hand also was noted (Figure 4). Upon cold exposure, the digits become pale white, cold, and numb; then blue; and finally red. She lacked other features of connective tissue disease, and autoantibody testing was negative. She also was noted to have an abnormal lateral curvature of the spine (scoliosis). Auditory, ocular, and neurologic examinations were normal. Cranial and cerebral magnetic resonance imaging showed no central nervous system abnormalities. Her family history was negative for nevus spilus, nevus sebaceous, and neurofibromatosis. The clinical findings in our patient led to the diagnosis of PPK.

Phacomatosis pigmentokeratotica is a distinctive epidermal nevus syndrome characterized by the coexistence of a speckled lentiginous nevus, also known as a nevus spilus, and a nevus sebaceous¹; PPK frequently is complicated by skeletal, ophthalmic, or neurologic abnormalities.² Most cases reported are sporadic, and a postzygotic mosaic HRas proto-oncogene, GTPase, HRAS, mutation has been demonstrated in some patients and may contribute to the phenotype of PPK.^3,4

Other anomalies have included ichthyosislike diffuse hyperkeratosis, laxity of the hands, pelvic hypoplasia, glaucoma, psychomotor retardation, and hypophosphatemic rickets. These patients also should be monitored for the development of malignant neoplasms within the nevus sebaceous.⁵ Segmental hyperhidrosis may be seen in association with the nevus spilus component.²

Raynaud phenomenon involving only the right hand was a unique finding in our patient. In 3 years of follow-up, our patient developed no evidence of connective tissue disease or other systemic illness. We speculate that Raynaud phenomenon of the right hand along with hyperhidrosis of the right side of the body could be a result of dysfunction of the autonomic nervous system. We propose that Raynaud phenomenon represents an unusual manifestation of PPK and may broaden the spectrum of extracutaneous anomalies associated with the disease. The finding of segmental nevi outside of the confines of the nevus spilus was another unusual manifestation of mosaicism.

 

To the Editor:

Phacomatosis pigmentokeratotica (PPK) is a rare epidermal nevus syndrome complicated by multiple extracutaneous anomalies, including skeletal defects and neurologic anomalies. Less common associations include lateral curvature of the spine and hyperhidrosis. We present a patient with PPK and unilateral Raynaud phenomenon in addition to a segmental distribution of melanocytic nevi, hyperhidrosis, and scoliosis.

A 9-year-old girl was born with a yellow-orange alopecic plaque on the right side of the scalp (Figure 1). There also were 2 large, irregularly pigmented patches localized on the right side of the upper back and buttock. Over 3 years, numerous papular nevi developed within these pigmented patches and were diagnosed as speckled lentiginous nevi (Figure 2). In addition, numerous nevi of various sizes affected the right face, right shoulder, right arm (Figure 3), and right neck and were clearly demarcated along the midline. Several nevi also were noted within the nevus sebaceous on the right scalp. These skin lesions expanded progressively with age. At 6 years of age, she was diagnosed with hyperhidrosis of the right half of the body, which was most pronounced on the face. Raynaud phenomenon restricted to the right hand also was noted (Figure 4). Upon cold exposure, the digits become pale white, cold, and numb; then blue; and finally red. She lacked other features of connective tissue disease, and autoantibody testing was negative. She also was noted to have an abnormal lateral curvature of the spine (scoliosis). Auditory, ocular, and neurologic examinations were normal. Cranial and cerebral magnetic resonance imaging showed no central nervous system abnormalities. Her family history was negative for nevus spilus, nevus sebaceous, and neurofibromatosis. The clinical findings in our patient led to the diagnosis of PPK.

Phacomatosis pigmentokeratotica is a distinctive epidermal nevus syndrome characterized by the coexistence of a speckled lentiginous nevus, also known as a nevus spilus, and a nevus sebaceous¹; PPK frequently is complicated by skeletal, ophthalmic, or neurologic abnormalities.² Most cases reported are sporadic, and a postzygotic mosaic HRas proto-oncogene, GTPase, HRAS, mutation has been demonstrated in some patients and may contribute to the phenotype of PPK.^3,4

Other anomalies have included ichthyosislike diffuse hyperkeratosis, laxity of the hands, pelvic hypoplasia, glaucoma, psychomotor retardation, and hypophosphatemic rickets. These patients also should be monitored for the development of malignant neoplasms within the nevus sebaceous.⁵ Segmental hyperhidrosis may be seen in association with the nevus spilus component.²

Raynaud phenomenon involving only the right hand was a unique finding in our patient. In 3 years of follow-up, our patient developed no evidence of connective tissue disease or other systemic illness. We speculate that Raynaud phenomenon of the right hand along with hyperhidrosis of the right side of the body could be a result of dysfunction of the autonomic nervous system. We propose that Raynaud phenomenon represents an unusual manifestation of PPK and may broaden the spectrum of extracutaneous anomalies associated with the disease. The finding of segmental nevi outside of the confines of the nevus spilus was another unusual manifestation of mosaicism.

 

To the Editor:

Phacomatosis pigmentokeratotica (PPK) is a rare epidermal nevus syndrome complicated by multiple extracutaneous anomalies, including skeletal defects and neurologic anomalies. Less common associations include lateral curvature of the spine and hyperhidrosis. We present a patient with PPK and unilateral Raynaud phenomenon in addition to a segmental distribution of melanocytic nevi, hyperhidrosis, and scoliosis.

A 9-year-old girl was born with a yellow-orange alopecic plaque on the right side of the scalp (Figure 1). There also were 2 large, irregularly pigmented patches localized on the right side of the upper back and buttock. Over 3 years, numerous papular nevi developed within these pigmented patches and were diagnosed as speckled lentiginous nevi (Figure 2). In addition, numerous nevi of various sizes affected the right face, right shoulder, right arm (Figure 3), and right neck and were clearly demarcated along the midline. Several nevi also were noted within the nevus sebaceous on the right scalp. These skin lesions expanded progressively with age. At 6 years of age, she was diagnosed with hyperhidrosis of the right half of the body, which was most pronounced on the face. Raynaud phenomenon restricted to the right hand also was noted (Figure 4). Upon cold exposure, the digits become pale white, cold, and numb; then blue; and finally red. She lacked other features of connective tissue disease, and autoantibody testing was negative. She also was noted to have an abnormal lateral curvature of the spine (scoliosis). Auditory, ocular, and neurologic examinations were normal. Cranial and cerebral magnetic resonance imaging showed no central nervous system abnormalities. Her family history was negative for nevus spilus, nevus sebaceous, and neurofibromatosis. The clinical findings in our patient led to the diagnosis of PPK.

Phacomatosis pigmentokeratotica is a distinctive epidermal nevus syndrome characterized by the coexistence of a speckled lentiginous nevus, also known as a nevus spilus, and a nevus sebaceous¹; PPK frequently is complicated by skeletal, ophthalmic, or neurologic abnormalities.² Most cases reported are sporadic, and a postzygotic mosaic HRas proto-oncogene, GTPase, HRAS, mutation has been demonstrated in some patients and may contribute to the phenotype of PPK.^3,4

Other anomalies have included ichthyosislike diffuse hyperkeratosis, laxity of the hands, pelvic hypoplasia, glaucoma, psychomotor retardation, and hypophosphatemic rickets. These patients also should be monitored for the development of malignant neoplasms within the nevus sebaceous.⁵ Segmental hyperhidrosis may be seen in association with the nevus spilus component.²

Raynaud phenomenon involving only the right hand was a unique finding in our patient. In 3 years of follow-up, our patient developed no evidence of connective tissue disease or other systemic illness. We speculate that Raynaud phenomenon of the right hand along with hyperhidrosis of the right side of the body could be a result of dysfunction of the autonomic nervous system. We propose that Raynaud phenomenon represents an unusual manifestation of PPK and may broaden the spectrum of extracutaneous anomalies associated with the disease. The finding of segmental nevi outside of the confines of the nevus spilus was another unusual manifestation of mosaicism.

The Diagnosis: Keratoderma Climactericum 

Keratoderma climactericum was first reported in 1934 by Haxthausen¹ as nonpruritic circumscribed hyperkeratosis located mainly on the palms and soles. The initial eruption was described as discrete lesions with an oval or round shape that progressed to less-defined, confluent, hyperkeratotic patches with fissures.¹ Keratoderma climactericum also may be referred to as Haxthausen disease and is considered an acquired palmoplantar keratoderma.² 

Keratoderma climactericum is a rare dermatologic disorder that presents in women of menopausal age who have no family or personal history of skin disease. Keratoderma climactericum is associated with hypertension and obesity.² Keratotic lesions usually first occur on the plantar surfaces with eventual development of fissuring and hyperkeratosis that causes painful walking. The keratotic lesions on the plantar surfaces often are nonpruritic and gradually become confluent over time. As the disease progresses, keratotic lesions appear on the central palms, which can lead to confluent hyperkeratosis on the palmar surfaces (Figure 1).² The exact mechanism of keratoderma climactericum has not been described but is believed to be due to hormonal dysregulation.²  

In 1986, Deschamps et al³ presented 10 cases of keratoderma climactericum occurring in menopausal women with an average age of 57 years. The lesions began on the soles at areas of greatest pressure. Histopathology for each patient showed orthokeratotic hyperkeratosis, irregular hyperplasia, interpapillary ridges, and exocytosis of lymphocytes in the epidermis. Seven patients were treated with etretinate, which first led to the removal of palmar lesions, followed by improvement in plantar lesions and pain when walking. There was no association of keratoderma climactericum and sex hormones, as hormone levels were negative or normal for each patient.³  

Three cases of keratoderma climactericum following bilateral oophorectomy in young women were reported by Wachtel⁴ in 1981. Unlike in women of menopausal age, there was no association of keratoderma climactericum with hypertension or obesity. Additionally, the lesions on the palms and soles were more diffusely distributed than in women of menopausal age. Estrogen administration completely reversed each patient's hyperkeratotic palms and soles.⁴ A definitive pathogenic role of estrogens in the development of keratoderma climactericum has yet to be determined^.2 

Histopathology is not specific for keratoderma climactericum, making the disease a clinical diagnosis. However, a biopsy may be useful to rule out palmoplantar psoriasis.² Clinical information such as the age and sex of the patient, distribution of disease, presence of fissuring, and progression of disease from soles to palms should be considered when making a diagnosis of keratoderma climactericum. The differential diagnosis of keratoderma climactericum should include fungal infections, contact dermatitis, irritant dermatitis, psoriasis, atopic dermatitis, underlying malignancy, and pityriasis rubra pilaris. 

Treatment options for keratoderma climactericum include salicylic acid, emollients, oral retinoids, urea ointments, estriol cream, and topical steroids.^5,6 Our patient was prescribed acitretin 25 mg daily and ammonium lactate to apply topically as needed for dry skin. Five months after the initial presentation, fissures and dry skin on the bilateral soles were still present. Ammonium lactate was discontinued, and the patient was prescribed urea cream 40%. Fifteen months after the initial presentation, the patient reported substantial improvement on the hands and feet and noted that she no longer needed the urea cream. Physical examination revealed no presence of hyperkeratosis or fissuring on the palms (Figure 2), and mild hyperkeratosis was present on the plantar surfaces of the feet (Figure 3). The patient continued to use acitretin to prevent disease relapse.  

Keratoderma climactericum is an unusual and debilitating condition that occurs in women of menopausal age. It is diagnosed by its specific clinical presentation. More common diagnoses such as tinea and dermatitis should be ruled out before considering keratoderma climactericum.  

The Diagnosis: Keratoderma Climactericum 

Keratoderma climactericum was first reported in 1934 by Haxthausen¹ as nonpruritic circumscribed hyperkeratosis located mainly on the palms and soles. The initial eruption was described as discrete lesions with an oval or round shape that progressed to less-defined, confluent, hyperkeratotic patches with fissures.¹ Keratoderma climactericum also may be referred to as Haxthausen disease and is considered an acquired palmoplantar keratoderma.² 

Keratoderma climactericum is a rare dermatologic disorder that presents in women of menopausal age who have no family or personal history of skin disease. Keratoderma climactericum is associated with hypertension and obesity.² Keratotic lesions usually first occur on the plantar surfaces with eventual development of fissuring and hyperkeratosis that causes painful walking. The keratotic lesions on the plantar surfaces often are nonpruritic and gradually become confluent over time. As the disease progresses, keratotic lesions appear on the central palms, which can lead to confluent hyperkeratosis on the palmar surfaces (Figure 1).² The exact mechanism of keratoderma climactericum has not been described but is believed to be due to hormonal dysregulation.²  

In 1986, Deschamps et al³ presented 10 cases of keratoderma climactericum occurring in menopausal women with an average age of 57 years. The lesions began on the soles at areas of greatest pressure. Histopathology for each patient showed orthokeratotic hyperkeratosis, irregular hyperplasia, interpapillary ridges, and exocytosis of lymphocytes in the epidermis. Seven patients were treated with etretinate, which first led to the removal of palmar lesions, followed by improvement in plantar lesions and pain when walking. There was no association of keratoderma climactericum and sex hormones, as hormone levels were negative or normal for each patient.³  

Three cases of keratoderma climactericum following bilateral oophorectomy in young women were reported by Wachtel⁴ in 1981. Unlike in women of menopausal age, there was no association of keratoderma climactericum with hypertension or obesity. Additionally, the lesions on the palms and soles were more diffusely distributed than in women of menopausal age. Estrogen administration completely reversed each patient's hyperkeratotic palms and soles.⁴ A definitive pathogenic role of estrogens in the development of keratoderma climactericum has yet to be determined^.2 

Histopathology is not specific for keratoderma climactericum, making the disease a clinical diagnosis. However, a biopsy may be useful to rule out palmoplantar psoriasis.² Clinical information such as the age and sex of the patient, distribution of disease, presence of fissuring, and progression of disease from soles to palms should be considered when making a diagnosis of keratoderma climactericum. The differential diagnosis of keratoderma climactericum should include fungal infections, contact dermatitis, irritant dermatitis, psoriasis, atopic dermatitis, underlying malignancy, and pityriasis rubra pilaris. 

Treatment options for keratoderma climactericum include salicylic acid, emollients, oral retinoids, urea ointments, estriol cream, and topical steroids.^5,6 Our patient was prescribed acitretin 25 mg daily and ammonium lactate to apply topically as needed for dry skin. Five months after the initial presentation, fissures and dry skin on the bilateral soles were still present. Ammonium lactate was discontinued, and the patient was prescribed urea cream 40%. Fifteen months after the initial presentation, the patient reported substantial improvement on the hands and feet and noted that she no longer needed the urea cream. Physical examination revealed no presence of hyperkeratosis or fissuring on the palms (Figure 2), and mild hyperkeratosis was present on the plantar surfaces of the feet (Figure 3). The patient continued to use acitretin to prevent disease relapse.  

Keratoderma climactericum is an unusual and debilitating condition that occurs in women of menopausal age. It is diagnosed by its specific clinical presentation. More common diagnoses such as tinea and dermatitis should be ruled out before considering keratoderma climactericum.  

The Diagnosis: Keratoderma Climactericum 

Keratoderma climactericum was first reported in 1934 by Haxthausen¹ as nonpruritic circumscribed hyperkeratosis located mainly on the palms and soles. The initial eruption was described as discrete lesions with an oval or round shape that progressed to less-defined, confluent, hyperkeratotic patches with fissures.¹ Keratoderma climactericum also may be referred to as Haxthausen disease and is considered an acquired palmoplantar keratoderma.² 

Keratoderma climactericum is a rare dermatologic disorder that presents in women of menopausal age who have no family or personal history of skin disease. Keratoderma climactericum is associated with hypertension and obesity.² Keratotic lesions usually first occur on the plantar surfaces with eventual development of fissuring and hyperkeratosis that causes painful walking. The keratotic lesions on the plantar surfaces often are nonpruritic and gradually become confluent over time. As the disease progresses, keratotic lesions appear on the central palms, which can lead to confluent hyperkeratosis on the palmar surfaces (Figure 1).² The exact mechanism of keratoderma climactericum has not been described but is believed to be due to hormonal dysregulation.²  

In 1986, Deschamps et al³ presented 10 cases of keratoderma climactericum occurring in menopausal women with an average age of 57 years. The lesions began on the soles at areas of greatest pressure. Histopathology for each patient showed orthokeratotic hyperkeratosis, irregular hyperplasia, interpapillary ridges, and exocytosis of lymphocytes in the epidermis. Seven patients were treated with etretinate, which first led to the removal of palmar lesions, followed by improvement in plantar lesions and pain when walking. There was no association of keratoderma climactericum and sex hormones, as hormone levels were negative or normal for each patient.³  

Three cases of keratoderma climactericum following bilateral oophorectomy in young women were reported by Wachtel⁴ in 1981. Unlike in women of menopausal age, there was no association of keratoderma climactericum with hypertension or obesity. Additionally, the lesions on the palms and soles were more diffusely distributed than in women of menopausal age. Estrogen administration completely reversed each patient's hyperkeratotic palms and soles.⁴ A definitive pathogenic role of estrogens in the development of keratoderma climactericum has yet to be determined^.2 

Histopathology is not specific for keratoderma climactericum, making the disease a clinical diagnosis. However, a biopsy may be useful to rule out palmoplantar psoriasis.² Clinical information such as the age and sex of the patient, distribution of disease, presence of fissuring, and progression of disease from soles to palms should be considered when making a diagnosis of keratoderma climactericum. The differential diagnosis of keratoderma climactericum should include fungal infections, contact dermatitis, irritant dermatitis, psoriasis, atopic dermatitis, underlying malignancy, and pityriasis rubra pilaris. 

Treatment options for keratoderma climactericum include salicylic acid, emollients, oral retinoids, urea ointments, estriol cream, and topical steroids.^5,6 Our patient was prescribed acitretin 25 mg daily and ammonium lactate to apply topically as needed for dry skin. Five months after the initial presentation, fissures and dry skin on the bilateral soles were still present. Ammonium lactate was discontinued, and the patient was prescribed urea cream 40%. Fifteen months after the initial presentation, the patient reported substantial improvement on the hands and feet and noted that she no longer needed the urea cream. Physical examination revealed no presence of hyperkeratosis or fissuring on the palms (Figure 2), and mild hyperkeratosis was present on the plantar surfaces of the feet (Figure 3). The patient continued to use acitretin to prevent disease relapse.  

Keratoderma climactericum is an unusual and debilitating condition that occurs in women of menopausal age. It is diagnosed by its specific clinical presentation. More common diagnoses such as tinea and dermatitis should be ruled out before considering keratoderma climactericum.  

The Diagnosis: Phytophotodermatitis 

A  more detailed patient history revealed that there was beer with limes on the boat, but the partygoers neglected to bring a knife. The patient volunteered to tear the limes apart with his bare hands. Because he was clad only in swim trunks, lime juice splattered over various regions of his body. 

Phytophotodermatitis is a phototoxic blistering rash that follows topical exposure to plant-derived furocoumarins and sunlight. (Figure) Furocoumarins are photosensitizing substances produced by certain plants, possibly as a defense mechanism against predators.¹ They cause a nonimmunologic phototoxic reaction when deposited on the skin and exposed to UVA radiation. Exposure to limes is the most common precipitant of phytophotodermatitis, but other potential culprits include lemons, grapefruit, figs, carrots, parsnips, celery, and dill.²  

Lesions associated with phytophotodermatitis classically present as painful erythematous patches and bullae in regions of furocoumarin exposure. Affected areas are well demarcated and irregularly shaped and heal with a characteristic hyperpigmented rim. They often have a downward streak pattern from the dripping juice.³ If the furocoumarins are transferred by touch, lesions can appear in the shape of handprints, which may raise alarms for physical abuse in children.⁴ 

Photochemical reactions caused by activated furocoumarins cross-link nuclear DNA and damage cell membranes. These changes lead to cellular death resulting in edema and destruction of the epidermis. Other effects include an increase in keratin and thickening of the stratum corneum. The hyperpigmentation is a result of increased concentration of melanosomes and stimulation of melanocytes by activated furocoumarins.⁵ 

Management of phytophotodermatitis depends on the severity of skin injury. Mild cases may not require any treatment, whereas the most severe ones require admission to a burn unit for wound care. Anti-inflammatory medications are the mainstay of therapy. Our patient was prescribed desonide cream 0.05% for application to the affected areas. Sunscreen should be applied to prevent worsening of hyperpigmentation, which may take months to years to fade naturally. If hyperpigmentation is cosmetically troubling to the patient, bleaching agents such as hydroquinone and retinoids or Nd:YAG laser can be used to accelerate the resolution of pigment.⁵ 

Phototoxicity differs from less common photoallergic reactions caused by preformed antibodies or a delayed cell-mediated response to a trigger. The classic presentation of photoallergy is apruritic, inflammatory, bullous eruption in a sensitized individual.⁶ Allergic contact dermatitis more commonly is associated with pruritus than pain, and it presents as a papulovesicular eruption that evolves into lichenified plaques.⁷ Porphyria cutanea tarda would likely be accompanied by other cutaneous features such as hypertrichosis and sclerodermoid plaques with dystrophic calcification, in addition to wine-colored urine-containing porphyrins.⁸ Bullous fixed drug eruptions develop within 48 hours of exposure to a causative agent. The patient typically would experience pruritus and burning at the site of clearly demarcated erythematous lesions that healed with hyperpigmentation.⁹ Lesions of bullous lupus erythematosus may appear in areas without sun exposure, and they would be more likely to leave behind hypopigmentation rather than hyperpigmentation.¹⁰ 

The Diagnosis: Phytophotodermatitis 

A  more detailed patient history revealed that there was beer with limes on the boat, but the partygoers neglected to bring a knife. The patient volunteered to tear the limes apart with his bare hands. Because he was clad only in swim trunks, lime juice splattered over various regions of his body. 

Phytophotodermatitis is a phototoxic blistering rash that follows topical exposure to plant-derived furocoumarins and sunlight. (Figure) Furocoumarins are photosensitizing substances produced by certain plants, possibly as a defense mechanism against predators.¹ They cause a nonimmunologic phototoxic reaction when deposited on the skin and exposed to UVA radiation. Exposure to limes is the most common precipitant of phytophotodermatitis, but other potential culprits include lemons, grapefruit, figs, carrots, parsnips, celery, and dill.²  

Lesions associated with phytophotodermatitis classically present as painful erythematous patches and bullae in regions of furocoumarin exposure. Affected areas are well demarcated and irregularly shaped and heal with a characteristic hyperpigmented rim. They often have a downward streak pattern from the dripping juice.³ If the furocoumarins are transferred by touch, lesions can appear in the shape of handprints, which may raise alarms for physical abuse in children.⁴ 

Photochemical reactions caused by activated furocoumarins cross-link nuclear DNA and damage cell membranes. These changes lead to cellular death resulting in edema and destruction of the epidermis. Other effects include an increase in keratin and thickening of the stratum corneum. The hyperpigmentation is a result of increased concentration of melanosomes and stimulation of melanocytes by activated furocoumarins.⁵ 

Management of phytophotodermatitis depends on the severity of skin injury. Mild cases may not require any treatment, whereas the most severe ones require admission to a burn unit for wound care. Anti-inflammatory medications are the mainstay of therapy. Our patient was prescribed desonide cream 0.05% for application to the affected areas. Sunscreen should be applied to prevent worsening of hyperpigmentation, which may take months to years to fade naturally. If hyperpigmentation is cosmetically troubling to the patient, bleaching agents such as hydroquinone and retinoids or Nd:YAG laser can be used to accelerate the resolution of pigment.⁵ 

Phototoxicity differs from less common photoallergic reactions caused by preformed antibodies or a delayed cell-mediated response to a trigger. The classic presentation of photoallergy is apruritic, inflammatory, bullous eruption in a sensitized individual.⁶ Allergic contact dermatitis more commonly is associated with pruritus than pain, and it presents as a papulovesicular eruption that evolves into lichenified plaques.⁷ Porphyria cutanea tarda would likely be accompanied by other cutaneous features such as hypertrichosis and sclerodermoid plaques with dystrophic calcification, in addition to wine-colored urine-containing porphyrins.⁸ Bullous fixed drug eruptions develop within 48 hours of exposure to a causative agent. The patient typically would experience pruritus and burning at the site of clearly demarcated erythematous lesions that healed with hyperpigmentation.⁹ Lesions of bullous lupus erythematosus may appear in areas without sun exposure, and they would be more likely to leave behind hypopigmentation rather than hyperpigmentation.¹⁰ 

The Diagnosis: Phytophotodermatitis 

A  more detailed patient history revealed that there was beer with limes on the boat, but the partygoers neglected to bring a knife. The patient volunteered to tear the limes apart with his bare hands. Because he was clad only in swim trunks, lime juice splattered over various regions of his body. 

Phytophotodermatitis is a phototoxic blistering rash that follows topical exposure to plant-derived furocoumarins and sunlight. (Figure) Furocoumarins are photosensitizing substances produced by certain plants, possibly as a defense mechanism against predators.¹ They cause a nonimmunologic phototoxic reaction when deposited on the skin and exposed to UVA radiation. Exposure to limes is the most common precipitant of phytophotodermatitis, but other potential culprits include lemons, grapefruit, figs, carrots, parsnips, celery, and dill.²  

Lesions associated with phytophotodermatitis classically present as painful erythematous patches and bullae in regions of furocoumarin exposure. Affected areas are well demarcated and irregularly shaped and heal with a characteristic hyperpigmented rim. They often have a downward streak pattern from the dripping juice.³ If the furocoumarins are transferred by touch, lesions can appear in the shape of handprints, which may raise alarms for physical abuse in children.⁴ 

Photochemical reactions caused by activated furocoumarins cross-link nuclear DNA and damage cell membranes. These changes lead to cellular death resulting in edema and destruction of the epidermis. Other effects include an increase in keratin and thickening of the stratum corneum. The hyperpigmentation is a result of increased concentration of melanosomes and stimulation of melanocytes by activated furocoumarins.⁵ 

Management of phytophotodermatitis depends on the severity of skin injury. Mild cases may not require any treatment, whereas the most severe ones require admission to a burn unit for wound care. Anti-inflammatory medications are the mainstay of therapy. Our patient was prescribed desonide cream 0.05% for application to the affected areas. Sunscreen should be applied to prevent worsening of hyperpigmentation, which may take months to years to fade naturally. If hyperpigmentation is cosmetically troubling to the patient, bleaching agents such as hydroquinone and retinoids or Nd:YAG laser can be used to accelerate the resolution of pigment.⁵ 

Phototoxicity differs from less common photoallergic reactions caused by preformed antibodies or a delayed cell-mediated response to a trigger. The classic presentation of photoallergy is apruritic, inflammatory, bullous eruption in a sensitized individual.⁶ Allergic contact dermatitis more commonly is associated with pruritus than pain, and it presents as a papulovesicular eruption that evolves into lichenified plaques.⁷ Porphyria cutanea tarda would likely be accompanied by other cutaneous features such as hypertrichosis and sclerodermoid plaques with dystrophic calcification, in addition to wine-colored urine-containing porphyrins.⁸ Bullous fixed drug eruptions develop within 48 hours of exposure to a causative agent. The patient typically would experience pruritus and burning at the site of clearly demarcated erythematous lesions that healed with hyperpigmentation.⁹ Lesions of bullous lupus erythematosus may appear in areas without sun exposure, and they would be more likely to leave behind hypopigmentation rather than hyperpigmentation.¹⁰ 

Sponges are among the oldest animals on earth, appearing more than 640 million years ago before the Cambrian explosion, a period when most major animal phyla appeared in the fossil records.¹ More than 10,000 species of sponges have been identified worldwide and are distributed from polar to tropical regions in both marine (Figure 1) and freshwater (Figure 2) environments. They inhabit both shallow waters as well as depths of more than 2800 m, with shallower sponges tending to be more vibrantly colored than their deeper counterparts. The wide-ranging habitats of sponges have led to size variations from as small as 0.05 mm to more than 3 m in height.² Their taxonomic phylum, Porifera (meaning pore bearers), is derived from the millions of pores lining the surface of the sponge that are used to filter planktonic organisms.³ Flagellated epithelioid cells called choanocytes line the internal chambers of sponges, creating a water current that promotes filter feeding as well as nutrient absorption across their microvilli.⁴ The body walls of many sponges consist of a collagenous skeleton made up of spongin and spicules of silicon dioxide (silica) or calcium carbonate embedded in the spongin connective tissue matrix.⁵ Bath sponges lack silica spicules.

Sponges have been used in medicine for centuries. The first use in Western culture was recorded in 405 bce in The Frogs, a comedy by Aristophanes in which a sponge was placed on a character’s heart following a syncopal episode. Additionally, in many Hippocratic writings, the use of sponges is outlined in the treatment of a variety of ailments. Similarly, the ancient Chinese and Greeks used burnt sponge and seaweed as a source of iodine to treat goiters.^6,7 Modern research focuses on the use of sponge metabolites for their antineoplastic, antimicrobial, and anti-inflammatory effects.⁸ Identification of spongouridine and spongothymidine from the sponge Tectitethya crypta led to the development of cytarabine and gemcitabine⁸ as well as the discovery of the antiviral agent vidarabine.⁹ The monoclonal antibody assay for the detection of shellfish poisoning was prepared using the sponge Halichondria okadai.¹⁰

Mechanisms and Symptoms of Injury

Bathing sponges (silk sponges) derived from Spongia officinalis are harmless. Other sponges can exert their damaging effects through a variety of mechanisms that lead to dermatologic manifestations (eTable). Some species of sponges produce and secrete toxic metabolites (eg, crinotoxins) onto the body surface or into the surrounding water. They also are capable of synthesizing a mucous slime that can be irritating to human skin. Direct trauma also can be caused by fragments of the silica or calcium carbonate sponge skeleton penetrating the skin. Stinging members of the phylum Cnidaria can colonize the sponge, leading to injury when a human handles the sponge.^25-27

Sponge dermatitis can be divided into 2 major categories: an initial pruritic dermatitis (Figure 3) that occurs within 20 minutes to a few hours after contact and a delayed irritant dermatitis caused by penetration of the spicules and chemical agents into skin.²⁸ Importantly, different species can lead to varying manifestations.

The initial pruritic dermatitis is characterized by itching and burning that progresses to local edema, vesiculation, joint swelling, and stiffness. Because most contact with sponges occurs with handling, joint immobility may ensue within 24 hours of the encounter. Rarely, larger areas of the skin are affected, and fever, chills, malaise, dizziness, nausea, purulent bullae, muscle cramps, and formication may occur.²⁸ Anaphylactic reactions have been described in a small subset of patients. There have even been reports of delayed (ie, 1–2 weeks following exposure) erythema multiforme, livedo reticularis, purpura, and dyshidrotic eczema.^16,20,29 The irritant dermatitis caused by spicule trauma is due to a foreign body reaction that can be exacerbated by toxins entering the skin. In severe cases, desquamation, recurrent eczema, and arthralgia can occur.³⁰ In general, more mild cases should self-resolve within 3 to 7 days. Dermatologic conditions also can be caused by organisms that inhabit sponges and as a result produce a dermatitis when the sponge is handled, including sponge divers disease (maladie des plongeurs), a necrotic dermatitis caused by stinging Cnidaria species.³¹ Dogger Bank itch, first described as a dermatitis caused by sensitization to (2-hydroxyethyl) dimethylsulfoxonium chloride, initially was isolated from the sea chervil (a type of Bryozoan); however, that same chemical also was later found in sponges, producing the same dermatitis after handling the sponge.³² Freshwater sponges also have been reported to be injurious and exist worldwide. In contrast to marine sponges, lesions from freshwater sponges are disseminated pruritic erythematous papules with ulcerations, crusts, and secondary infections.²² The disseminated nature of the dermatitis caused by freshwater sponges is due to contact with the spicules of dead sponges that are dispersed throughout the water rather than from direct handling. Sponge dermatitis occurs mostly in sponge collectors, divers, trawlers, and biology students and has been reported extensively in the United States, Caribbean Islands, Australia, New Zealand, and Brazil.^18,27,33,34

Management

Treatment should consist of an initial decontamination; the skin should be dried, and adhesive tape or rubber cement should be utilized to remove any spicules embedded in the skin. Diluted vinegar soaks should be initiated for 10 to 30 minutes on the affected area(s) 3 or 4 times daily.¹⁹ The initial decontamination should occur immediately, as delay may lead to persistent purulent bullae that may take months to heal. Topical steroids may be used following the initial decontamination to help relieve inflammation. Antihistamines and nonsteroidal anti-inflammatory drugs may be used to alleviate pruritus and pain, respectively. Severe cases may require systemic glucocorticoids. Additionally, immunization status against tetanus toxoid should be assessed.³⁵ In the event of an anaphylactic reaction, it is important to maintain a patent airway and normalized blood pressure through the use of intramuscular epinephrine.³⁶ Frequent follow-up is warranted, as serious secondary infections can develop.³⁷ Patients also should be counseled on the potential for delayed dermatologic reactions, including erythema multiforme. Contact between humans and coastal environments has been increasing in the last few decades; therefore, an increase in contact with sponges is to be expected.²²

Sponges are among the oldest animals on earth, appearing more than 640 million years ago before the Cambrian explosion, a period when most major animal phyla appeared in the fossil records.¹ More than 10,000 species of sponges have been identified worldwide and are distributed from polar to tropical regions in both marine (Figure 1) and freshwater (Figure 2) environments. They inhabit both shallow waters as well as depths of more than 2800 m, with shallower sponges tending to be more vibrantly colored than their deeper counterparts. The wide-ranging habitats of sponges have led to size variations from as small as 0.05 mm to more than 3 m in height.² Their taxonomic phylum, Porifera (meaning pore bearers), is derived from the millions of pores lining the surface of the sponge that are used to filter planktonic organisms.³ Flagellated epithelioid cells called choanocytes line the internal chambers of sponges, creating a water current that promotes filter feeding as well as nutrient absorption across their microvilli.⁴ The body walls of many sponges consist of a collagenous skeleton made up of spongin and spicules of silicon dioxide (silica) or calcium carbonate embedded in the spongin connective tissue matrix.⁵ Bath sponges lack silica spicules.

Sponges have been used in medicine for centuries. The first use in Western culture was recorded in 405 bce in The Frogs, a comedy by Aristophanes in which a sponge was placed on a character’s heart following a syncopal episode. Additionally, in many Hippocratic writings, the use of sponges is outlined in the treatment of a variety of ailments. Similarly, the ancient Chinese and Greeks used burnt sponge and seaweed as a source of iodine to treat goiters.^6,7 Modern research focuses on the use of sponge metabolites for their antineoplastic, antimicrobial, and anti-inflammatory effects.⁸ Identification of spongouridine and spongothymidine from the sponge Tectitethya crypta led to the development of cytarabine and gemcitabine⁸ as well as the discovery of the antiviral agent vidarabine.⁹ The monoclonal antibody assay for the detection of shellfish poisoning was prepared using the sponge Halichondria okadai.¹⁰

Mechanisms and Symptoms of Injury

Bathing sponges (silk sponges) derived from Spongia officinalis are harmless. Other sponges can exert their damaging effects through a variety of mechanisms that lead to dermatologic manifestations (eTable). Some species of sponges produce and secrete toxic metabolites (eg, crinotoxins) onto the body surface or into the surrounding water. They also are capable of synthesizing a mucous slime that can be irritating to human skin. Direct trauma also can be caused by fragments of the silica or calcium carbonate sponge skeleton penetrating the skin. Stinging members of the phylum Cnidaria can colonize the sponge, leading to injury when a human handles the sponge.^25-27

Sponge dermatitis can be divided into 2 major categories: an initial pruritic dermatitis (Figure 3) that occurs within 20 minutes to a few hours after contact and a delayed irritant dermatitis caused by penetration of the spicules and chemical agents into skin.²⁸ Importantly, different species can lead to varying manifestations.

The initial pruritic dermatitis is characterized by itching and burning that progresses to local edema, vesiculation, joint swelling, and stiffness. Because most contact with sponges occurs with handling, joint immobility may ensue within 24 hours of the encounter. Rarely, larger areas of the skin are affected, and fever, chills, malaise, dizziness, nausea, purulent bullae, muscle cramps, and formication may occur.²⁸ Anaphylactic reactions have been described in a small subset of patients. There have even been reports of delayed (ie, 1–2 weeks following exposure) erythema multiforme, livedo reticularis, purpura, and dyshidrotic eczema.^16,20,29 The irritant dermatitis caused by spicule trauma is due to a foreign body reaction that can be exacerbated by toxins entering the skin. In severe cases, desquamation, recurrent eczema, and arthralgia can occur.³⁰ In general, more mild cases should self-resolve within 3 to 7 days. Dermatologic conditions also can be caused by organisms that inhabit sponges and as a result produce a dermatitis when the sponge is handled, including sponge divers disease (maladie des plongeurs), a necrotic dermatitis caused by stinging Cnidaria species.³¹ Dogger Bank itch, first described as a dermatitis caused by sensitization to (2-hydroxyethyl) dimethylsulfoxonium chloride, initially was isolated from the sea chervil (a type of Bryozoan); however, that same chemical also was later found in sponges, producing the same dermatitis after handling the sponge.³² Freshwater sponges also have been reported to be injurious and exist worldwide. In contrast to marine sponges, lesions from freshwater sponges are disseminated pruritic erythematous papules with ulcerations, crusts, and secondary infections.²² The disseminated nature of the dermatitis caused by freshwater sponges is due to contact with the spicules of dead sponges that are dispersed throughout the water rather than from direct handling. Sponge dermatitis occurs mostly in sponge collectors, divers, trawlers, and biology students and has been reported extensively in the United States, Caribbean Islands, Australia, New Zealand, and Brazil.^18,27,33,34

Management

Treatment should consist of an initial decontamination; the skin should be dried, and adhesive tape or rubber cement should be utilized to remove any spicules embedded in the skin. Diluted vinegar soaks should be initiated for 10 to 30 minutes on the affected area(s) 3 or 4 times daily.¹⁹ The initial decontamination should occur immediately, as delay may lead to persistent purulent bullae that may take months to heal. Topical steroids may be used following the initial decontamination to help relieve inflammation. Antihistamines and nonsteroidal anti-inflammatory drugs may be used to alleviate pruritus and pain, respectively. Severe cases may require systemic glucocorticoids. Additionally, immunization status against tetanus toxoid should be assessed.³⁵ In the event of an anaphylactic reaction, it is important to maintain a patent airway and normalized blood pressure through the use of intramuscular epinephrine.³⁶ Frequent follow-up is warranted, as serious secondary infections can develop.³⁷ Patients also should be counseled on the potential for delayed dermatologic reactions, including erythema multiforme. Contact between humans and coastal environments has been increasing in the last few decades; therefore, an increase in contact with sponges is to be expected.²²

Sponges are among the oldest animals on earth, appearing more than 640 million years ago before the Cambrian explosion, a period when most major animal phyla appeared in the fossil records.¹ More than 10,000 species of sponges have been identified worldwide and are distributed from polar to tropical regions in both marine (Figure 1) and freshwater (Figure 2) environments. They inhabit both shallow waters as well as depths of more than 2800 m, with shallower sponges tending to be more vibrantly colored than their deeper counterparts. The wide-ranging habitats of sponges have led to size variations from as small as 0.05 mm to more than 3 m in height.² Their taxonomic phylum, Porifera (meaning pore bearers), is derived from the millions of pores lining the surface of the sponge that are used to filter planktonic organisms.³ Flagellated epithelioid cells called choanocytes line the internal chambers of sponges, creating a water current that promotes filter feeding as well as nutrient absorption across their microvilli.⁴ The body walls of many sponges consist of a collagenous skeleton made up of spongin and spicules of silicon dioxide (silica) or calcium carbonate embedded in the spongin connective tissue matrix.⁵ Bath sponges lack silica spicules.

Sponges have been used in medicine for centuries. The first use in Western culture was recorded in 405 bce in The Frogs, a comedy by Aristophanes in which a sponge was placed on a character’s heart following a syncopal episode. Additionally, in many Hippocratic writings, the use of sponges is outlined in the treatment of a variety of ailments. Similarly, the ancient Chinese and Greeks used burnt sponge and seaweed as a source of iodine to treat goiters.^6,7 Modern research focuses on the use of sponge metabolites for their antineoplastic, antimicrobial, and anti-inflammatory effects.⁸ Identification of spongouridine and spongothymidine from the sponge Tectitethya crypta led to the development of cytarabine and gemcitabine⁸ as well as the discovery of the antiviral agent vidarabine.⁹ The monoclonal antibody assay for the detection of shellfish poisoning was prepared using the sponge Halichondria okadai.¹⁰

Mechanisms and Symptoms of Injury

Bathing sponges (silk sponges) derived from Spongia officinalis are harmless. Other sponges can exert their damaging effects through a variety of mechanisms that lead to dermatologic manifestations (eTable). Some species of sponges produce and secrete toxic metabolites (eg, crinotoxins) onto the body surface or into the surrounding water. They also are capable of synthesizing a mucous slime that can be irritating to human skin. Direct trauma also can be caused by fragments of the silica or calcium carbonate sponge skeleton penetrating the skin. Stinging members of the phylum Cnidaria can colonize the sponge, leading to injury when a human handles the sponge.^25-27

Sponge dermatitis can be divided into 2 major categories: an initial pruritic dermatitis (Figure 3) that occurs within 20 minutes to a few hours after contact and a delayed irritant dermatitis caused by penetration of the spicules and chemical agents into skin.²⁸ Importantly, different species can lead to varying manifestations.

The initial pruritic dermatitis is characterized by itching and burning that progresses to local edema, vesiculation, joint swelling, and stiffness. Because most contact with sponges occurs with handling, joint immobility may ensue within 24 hours of the encounter. Rarely, larger areas of the skin are affected, and fever, chills, malaise, dizziness, nausea, purulent bullae, muscle cramps, and formication may occur.²⁸ Anaphylactic reactions have been described in a small subset of patients. There have even been reports of delayed (ie, 1–2 weeks following exposure) erythema multiforme, livedo reticularis, purpura, and dyshidrotic eczema.^16,20,29 The irritant dermatitis caused by spicule trauma is due to a foreign body reaction that can be exacerbated by toxins entering the skin. In severe cases, desquamation, recurrent eczema, and arthralgia can occur.³⁰ In general, more mild cases should self-resolve within 3 to 7 days. Dermatologic conditions also can be caused by organisms that inhabit sponges and as a result produce a dermatitis when the sponge is handled, including sponge divers disease (maladie des plongeurs), a necrotic dermatitis caused by stinging Cnidaria species.³¹ Dogger Bank itch, first described as a dermatitis caused by sensitization to (2-hydroxyethyl) dimethylsulfoxonium chloride, initially was isolated from the sea chervil (a type of Bryozoan); however, that same chemical also was later found in sponges, producing the same dermatitis after handling the sponge.³² Freshwater sponges also have been reported to be injurious and exist worldwide. In contrast to marine sponges, lesions from freshwater sponges are disseminated pruritic erythematous papules with ulcerations, crusts, and secondary infections.²² The disseminated nature of the dermatitis caused by freshwater sponges is due to contact with the spicules of dead sponges that are dispersed throughout the water rather than from direct handling. Sponge dermatitis occurs mostly in sponge collectors, divers, trawlers, and biology students and has been reported extensively in the United States, Caribbean Islands, Australia, New Zealand, and Brazil.^18,27,33,34

Management

Treatment should consist of an initial decontamination; the skin should be dried, and adhesive tape or rubber cement should be utilized to remove any spicules embedded in the skin. Diluted vinegar soaks should be initiated for 10 to 30 minutes on the affected area(s) 3 or 4 times daily.¹⁹ The initial decontamination should occur immediately, as delay may lead to persistent purulent bullae that may take months to heal. Topical steroids may be used following the initial decontamination to help relieve inflammation. Antihistamines and nonsteroidal anti-inflammatory drugs may be used to alleviate pruritus and pain, respectively. Severe cases may require systemic glucocorticoids. Additionally, immunization status against tetanus toxoid should be assessed.³⁵ In the event of an anaphylactic reaction, it is important to maintain a patent airway and normalized blood pressure through the use of intramuscular epinephrine.³⁶ Frequent follow-up is warranted, as serious secondary infections can develop.³⁷ Patients also should be counseled on the potential for delayed dermatologic reactions, including erythema multiforme. Contact between humans and coastal environments has been increasing in the last few decades; therefore, an increase in contact with sponges is to be expected.²²

 

Characteristics

The ubiquitous human flea, Pulex irritans, is a hematophagous wingless ectoparasite in the order Siphonaptera (wingless siphon) that survives by consuming the blood of its mammalian and avian hosts. Due to diseases such as the bubonic plague, fleas have claimed more victims than all the wars ever fought; in the 14th century, the Black Death caused more than 200 million deaths. Fleas fossilized in amber have been found to be 200 million years old and closely resemble the modern human flea, demonstrating the resilience of the species.

The adult human flea is a small, reddish brown, laterally compressed, wingless insect that is approximately 2- to 3.5-mm long (females, 2.5–3.5 mm; males, 2–2.5 mm) and enclosed by a tough cuticle. Compared to the dog flea (Ctenocephalides canis) and cat flea (Ctenocephalides felis), P irritans has no combs or ctenidia (Figure 1). Fleas have large powerful hind legs enabling them to jump horizontally or vertically 200 times their body length (equivalent to a 6-foot human jumping 1200 feet) using stored muscle energy in a pad on the hind legs composed of the elastic protein resilin.¹ They feed off a wide variety of hosts, including humans, pigs, cats, dogs, goats, sheep, cattle, chickens, owls, foxes, rabbits, mice, and feral cats. The flea’s mouthparts are highly specialized for piercing the skin and sucking its blood meal via direct capillary cannulation.

Life Cycle

There are 4 stages of the flea life cycle: egg, larva, pupa, and adult. Most adult flea species mate on the host; the female will lay an average of 4 to 8 small white eggs on the host after each blood meal, laying more than 400 eggs during her lifetime. The eggs then drop from the host and hatch in approximately 4 to 6 days to become larvae. The active larvae feed on available organic matter in their environment, such as their parents’ feces and detritus, while undergoing 3 molts within 1 week to several months.² The larva then spins a silken cocoon from modified salivary glands to form the pupa. In favorable conditions, the pupa lasts only a few weeks; however, it can last for a year or more in unfavorable conditions. Triggers for emergence of the adult flea from the pupa include high humidity, warm temperatures, increased levels of carbon dioxide, and vibrations including sound. An adult P irritans flea can live for a few weeks to more than 1.5 years in favorable conditions of lower air temperature, high relative humidity, and access to a host.³

Related Diseases

Pulex irritans can be a vector for several human diseases. Yersinia pestis is a gram-negative bacteria that causes plague, a highly virulent disease that killed millions of people during its 3 largest human pandemics. The black rat (Rattus rattus) and the oriental rat flea (Xenopsylla cheopis) have been implicated as initial vectors; however, transmission may be human-to-human with pneumonic plague, and septicemic plague may be spread via Pulex fleas or body lice.^4,5 In 1971, Y pestis was isolated from P irritans on a dog in the home of a plague patient in Kayenta, Arizona.⁶Yersinia pestis bacterial DNA also was extracted from P irritans during a plague outbreak in Madagascar in 2014⁷ and was implicated in epidemiologic studies of plague in Tanzania from 1986 to 2004, suggesting it also plays a role in endemic disease.⁸

Bartonellosis is an emerging disease caused by different species of the gram-negative intracellular bacteria of the genus Bartonella transmitted by lice, ticks, and fleas. Bartonella quintana causes trench fever primarily transmitted by the human body louse, Pediculus humanus corporis, and resulted in more than 1 million cases during World War I. Trench fever is characterized by headache, fever, dizziness, and shin pain that lasts 1 to 3 days and recurs in cycles every 4 to 6 days. Other clinical manifestations of B quintana include chronic bacteremia, endocarditis, lymphadenopathy, and bacillary angiomatosis.⁹Bartonella henselae causes cat scratch fever, characterized by lymphadenopathy, fever, headache, joint pain, and lethargy from infected cat scratches or the bite of an infected flea. Bartonella rochalimae also has been found to cause a trench fever–like bacteremia.¹⁰Bartonella species have been found in P irritans, and the flea is implicated as a vector of bartonellosis in humans.^11-15

Rickettsioses are worldwide diseases caused by the gram-negative intracellular bacteria of the genus Rickettsia transmitted to humans via hematophagous arthropods. The rickettsiae traditionally have been classified into the spotted fever or typhus groups. The spotted fever group (ie, Rocky Mountain spotted fever, Mediterranean spotted fever) is transmitted via ticks. The typhus group is transmitted via lice (epidemic typhus) and fleas (endemic or murine typhus). Murine typhus can be caused by Rickettsia typhi in warm coastal areas around the world where the main mammal reservoir is the rat and the rat flea vector X cheopis. Clinical signs of infection are abrupt onset of fever, headaches, myalgia, malaise, and chills, with a truncal maculopapular rash progressing peripherally several days after the initial clinical signs. Rash is present in up to 50% of cases.¹⁶Rickettsia felis is an emerging flea-borne pathogen causing an acute febrile illness usually transmitted via the cat flea C felis.¹⁷Rickettsia species DNA have been found to be present in P irritans from dogs¹⁸ and livestock¹⁹ and pose a risk for causing rickettsioses in humans.

Environmental Treatment and Prevention

Flea bites present as intense, pruritic, urticarial to vesicular papules that usually are located on the lower extremities but also can be present on exposed areas of the upper extremities and hands (Figure 2). Human fleas infest clothing, and bites can be widespread. Topical antipruritics and corticosteroids can be used for controlling itch and the intense cutaneous inflammatory response. The flea host should be identified in areas of the home, school, farm, work, or local environment. House pets should be examined and treated by a veterinarian. The pet’s bedding should be washed and dried at high temperatures, and carpets and floors should be routinely vacuumed or cleaned to remove eggs, larvae, flea feces, and/or pupae. The killing of adult fleas with insecticidal products (eg, imidacloprid, fipronil, spinosad, selamectin, lufenuron, ivermectin) is the primary method of flea control. Use of insect growth regulators such as pyriproxyfen inhibits adult reproduction and blocks the organogenesis of immature larval stages via hormonal or enzymatic actions.²⁰ The combination of an insecticide and an insect growth regulator appears to be most effective in their synergistic actions against adult fleas and larvae. There have been reports of insecticidal resistance in the flea population, especially with pyrethroids.^21,22 A professional exterminator and veterinarian should be consulted. In recalcitrant cases, evaluation for other wild mammals or birds should be performed in unoccupied areas of the home such as the attic, crawl spaces, and basements, as well as inside walls.

 

Conclusion

The human flea, P irritans, is an important vector in the transmission of human diseases such as the bubonic plague, bartonellosis, and rickettsioses. Flea bites present as intensely pruritic, urticarial to vesicular papules that most commonly present on the lower extremities. Flea bites can be treated with topical steroids, and fleas can be controlled by a combination of insecticidal products and insect growth regulators.

 

Characteristics

The ubiquitous human flea, Pulex irritans, is a hematophagous wingless ectoparasite in the order Siphonaptera (wingless siphon) that survives by consuming the blood of its mammalian and avian hosts. Due to diseases such as the bubonic plague, fleas have claimed more victims than all the wars ever fought; in the 14th century, the Black Death caused more than 200 million deaths. Fleas fossilized in amber have been found to be 200 million years old and closely resemble the modern human flea, demonstrating the resilience of the species.

The adult human flea is a small, reddish brown, laterally compressed, wingless insect that is approximately 2- to 3.5-mm long (females, 2.5–3.5 mm; males, 2–2.5 mm) and enclosed by a tough cuticle. Compared to the dog flea (Ctenocephalides canis) and cat flea (Ctenocephalides felis), P irritans has no combs or ctenidia (Figure 1). Fleas have large powerful hind legs enabling them to jump horizontally or vertically 200 times their body length (equivalent to a 6-foot human jumping 1200 feet) using stored muscle energy in a pad on the hind legs composed of the elastic protein resilin.¹ They feed off a wide variety of hosts, including humans, pigs, cats, dogs, goats, sheep, cattle, chickens, owls, foxes, rabbits, mice, and feral cats. The flea’s mouthparts are highly specialized for piercing the skin and sucking its blood meal via direct capillary cannulation.

Life Cycle

There are 4 stages of the flea life cycle: egg, larva, pupa, and adult. Most adult flea species mate on the host; the female will lay an average of 4 to 8 small white eggs on the host after each blood meal, laying more than 400 eggs during her lifetime. The eggs then drop from the host and hatch in approximately 4 to 6 days to become larvae. The active larvae feed on available organic matter in their environment, such as their parents’ feces and detritus, while undergoing 3 molts within 1 week to several months.² The larva then spins a silken cocoon from modified salivary glands to form the pupa. In favorable conditions, the pupa lasts only a few weeks; however, it can last for a year or more in unfavorable conditions. Triggers for emergence of the adult flea from the pupa include high humidity, warm temperatures, increased levels of carbon dioxide, and vibrations including sound. An adult P irritans flea can live for a few weeks to more than 1.5 years in favorable conditions of lower air temperature, high relative humidity, and access to a host.³

Related Diseases

Pulex irritans can be a vector for several human diseases. Yersinia pestis is a gram-negative bacteria that causes plague, a highly virulent disease that killed millions of people during its 3 largest human pandemics. The black rat (Rattus rattus) and the oriental rat flea (Xenopsylla cheopis) have been implicated as initial vectors; however, transmission may be human-to-human with pneumonic plague, and septicemic plague may be spread via Pulex fleas or body lice.^4,5 In 1971, Y pestis was isolated from P irritans on a dog in the home of a plague patient in Kayenta, Arizona.⁶Yersinia pestis bacterial DNA also was extracted from P irritans during a plague outbreak in Madagascar in 2014⁷ and was implicated in epidemiologic studies of plague in Tanzania from 1986 to 2004, suggesting it also plays a role in endemic disease.⁸

Bartonellosis is an emerging disease caused by different species of the gram-negative intracellular bacteria of the genus Bartonella transmitted by lice, ticks, and fleas. Bartonella quintana causes trench fever primarily transmitted by the human body louse, Pediculus humanus corporis, and resulted in more than 1 million cases during World War I. Trench fever is characterized by headache, fever, dizziness, and shin pain that lasts 1 to 3 days and recurs in cycles every 4 to 6 days. Other clinical manifestations of B quintana include chronic bacteremia, endocarditis, lymphadenopathy, and bacillary angiomatosis.⁹Bartonella henselae causes cat scratch fever, characterized by lymphadenopathy, fever, headache, joint pain, and lethargy from infected cat scratches or the bite of an infected flea. Bartonella rochalimae also has been found to cause a trench fever–like bacteremia.¹⁰Bartonella species have been found in P irritans, and the flea is implicated as a vector of bartonellosis in humans.^11-15

Rickettsioses are worldwide diseases caused by the gram-negative intracellular bacteria of the genus Rickettsia transmitted to humans via hematophagous arthropods. The rickettsiae traditionally have been classified into the spotted fever or typhus groups. The spotted fever group (ie, Rocky Mountain spotted fever, Mediterranean spotted fever) is transmitted via ticks. The typhus group is transmitted via lice (epidemic typhus) and fleas (endemic or murine typhus). Murine typhus can be caused by Rickettsia typhi in warm coastal areas around the world where the main mammal reservoir is the rat and the rat flea vector X cheopis. Clinical signs of infection are abrupt onset of fever, headaches, myalgia, malaise, and chills, with a truncal maculopapular rash progressing peripherally several days after the initial clinical signs. Rash is present in up to 50% of cases.¹⁶Rickettsia felis is an emerging flea-borne pathogen causing an acute febrile illness usually transmitted via the cat flea C felis.¹⁷Rickettsia species DNA have been found to be present in P irritans from dogs¹⁸ and livestock¹⁹ and pose a risk for causing rickettsioses in humans.

Environmental Treatment and Prevention

Flea bites present as intense, pruritic, urticarial to vesicular papules that usually are located on the lower extremities but also can be present on exposed areas of the upper extremities and hands (Figure 2). Human fleas infest clothing, and bites can be widespread. Topical antipruritics and corticosteroids can be used for controlling itch and the intense cutaneous inflammatory response. The flea host should be identified in areas of the home, school, farm, work, or local environment. House pets should be examined and treated by a veterinarian. The pet’s bedding should be washed and dried at high temperatures, and carpets and floors should be routinely vacuumed or cleaned to remove eggs, larvae, flea feces, and/or pupae. The killing of adult fleas with insecticidal products (eg, imidacloprid, fipronil, spinosad, selamectin, lufenuron, ivermectin) is the primary method of flea control. Use of insect growth regulators such as pyriproxyfen inhibits adult reproduction and blocks the organogenesis of immature larval stages via hormonal or enzymatic actions.²⁰ The combination of an insecticide and an insect growth regulator appears to be most effective in their synergistic actions against adult fleas and larvae. There have been reports of insecticidal resistance in the flea population, especially with pyrethroids.^21,22 A professional exterminator and veterinarian should be consulted. In recalcitrant cases, evaluation for other wild mammals or birds should be performed in unoccupied areas of the home such as the attic, crawl spaces, and basements, as well as inside walls.

 

Conclusion

The human flea, P irritans, is an important vector in the transmission of human diseases such as the bubonic plague, bartonellosis, and rickettsioses. Flea bites present as intensely pruritic, urticarial to vesicular papules that most commonly present on the lower extremities. Flea bites can be treated with topical steroids, and fleas can be controlled by a combination of insecticidal products and insect growth regulators.

 

Characteristics

The ubiquitous human flea, Pulex irritans, is a hematophagous wingless ectoparasite in the order Siphonaptera (wingless siphon) that survives by consuming the blood of its mammalian and avian hosts. Due to diseases such as the bubonic plague, fleas have claimed more victims than all the wars ever fought; in the 14th century, the Black Death caused more than 200 million deaths. Fleas fossilized in amber have been found to be 200 million years old and closely resemble the modern human flea, demonstrating the resilience of the species.

The adult human flea is a small, reddish brown, laterally compressed, wingless insect that is approximately 2- to 3.5-mm long (females, 2.5–3.5 mm; males, 2–2.5 mm) and enclosed by a tough cuticle. Compared to the dog flea (Ctenocephalides canis) and cat flea (Ctenocephalides felis), P irritans has no combs or ctenidia (Figure 1). Fleas have large powerful hind legs enabling them to jump horizontally or vertically 200 times their body length (equivalent to a 6-foot human jumping 1200 feet) using stored muscle energy in a pad on the hind legs composed of the elastic protein resilin.¹ They feed off a wide variety of hosts, including humans, pigs, cats, dogs, goats, sheep, cattle, chickens, owls, foxes, rabbits, mice, and feral cats. The flea’s mouthparts are highly specialized for piercing the skin and sucking its blood meal via direct capillary cannulation.

Life Cycle

There are 4 stages of the flea life cycle: egg, larva, pupa, and adult. Most adult flea species mate on the host; the female will lay an average of 4 to 8 small white eggs on the host after each blood meal, laying more than 400 eggs during her lifetime. The eggs then drop from the host and hatch in approximately 4 to 6 days to become larvae. The active larvae feed on available organic matter in their environment, such as their parents’ feces and detritus, while undergoing 3 molts within 1 week to several months.² The larva then spins a silken cocoon from modified salivary glands to form the pupa. In favorable conditions, the pupa lasts only a few weeks; however, it can last for a year or more in unfavorable conditions. Triggers for emergence of the adult flea from the pupa include high humidity, warm temperatures, increased levels of carbon dioxide, and vibrations including sound. An adult P irritans flea can live for a few weeks to more than 1.5 years in favorable conditions of lower air temperature, high relative humidity, and access to a host.³

Related Diseases

Pulex irritans can be a vector for several human diseases. Yersinia pestis is a gram-negative bacteria that causes plague, a highly virulent disease that killed millions of people during its 3 largest human pandemics. The black rat (Rattus rattus) and the oriental rat flea (Xenopsylla cheopis) have been implicated as initial vectors; however, transmission may be human-to-human with pneumonic plague, and septicemic plague may be spread via Pulex fleas or body lice.^4,5 In 1971, Y pestis was isolated from P irritans on a dog in the home of a plague patient in Kayenta, Arizona.⁶Yersinia pestis bacterial DNA also was extracted from P irritans during a plague outbreak in Madagascar in 2014⁷ and was implicated in epidemiologic studies of plague in Tanzania from 1986 to 2004, suggesting it also plays a role in endemic disease.⁸

Bartonellosis is an emerging disease caused by different species of the gram-negative intracellular bacteria of the genus Bartonella transmitted by lice, ticks, and fleas. Bartonella quintana causes trench fever primarily transmitted by the human body louse, Pediculus humanus corporis, and resulted in more than 1 million cases during World War I. Trench fever is characterized by headache, fever, dizziness, and shin pain that lasts 1 to 3 days and recurs in cycles every 4 to 6 days. Other clinical manifestations of B quintana include chronic bacteremia, endocarditis, lymphadenopathy, and bacillary angiomatosis.⁹Bartonella henselae causes cat scratch fever, characterized by lymphadenopathy, fever, headache, joint pain, and lethargy from infected cat scratches or the bite of an infected flea. Bartonella rochalimae also has been found to cause a trench fever–like bacteremia.¹⁰Bartonella species have been found in P irritans, and the flea is implicated as a vector of bartonellosis in humans.^11-15

Rickettsioses are worldwide diseases caused by the gram-negative intracellular bacteria of the genus Rickettsia transmitted to humans via hematophagous arthropods. The rickettsiae traditionally have been classified into the spotted fever or typhus groups. The spotted fever group (ie, Rocky Mountain spotted fever, Mediterranean spotted fever) is transmitted via ticks. The typhus group is transmitted via lice (epidemic typhus) and fleas (endemic or murine typhus). Murine typhus can be caused by Rickettsia typhi in warm coastal areas around the world where the main mammal reservoir is the rat and the rat flea vector X cheopis. Clinical signs of infection are abrupt onset of fever, headaches, myalgia, malaise, and chills, with a truncal maculopapular rash progressing peripherally several days after the initial clinical signs. Rash is present in up to 50% of cases.¹⁶Rickettsia felis is an emerging flea-borne pathogen causing an acute febrile illness usually transmitted via the cat flea C felis.¹⁷Rickettsia species DNA have been found to be present in P irritans from dogs¹⁸ and livestock¹⁹ and pose a risk for causing rickettsioses in humans.

Environmental Treatment and Prevention

Flea bites present as intense, pruritic, urticarial to vesicular papules that usually are located on the lower extremities but also can be present on exposed areas of the upper extremities and hands (Figure 2). Human fleas infest clothing, and bites can be widespread. Topical antipruritics and corticosteroids can be used for controlling itch and the intense cutaneous inflammatory response. The flea host should be identified in areas of the home, school, farm, work, or local environment. House pets should be examined and treated by a veterinarian. The pet’s bedding should be washed and dried at high temperatures, and carpets and floors should be routinely vacuumed or cleaned to remove eggs, larvae, flea feces, and/or pupae. The killing of adult fleas with insecticidal products (eg, imidacloprid, fipronil, spinosad, selamectin, lufenuron, ivermectin) is the primary method of flea control. Use of insect growth regulators such as pyriproxyfen inhibits adult reproduction and blocks the organogenesis of immature larval stages via hormonal or enzymatic actions.²⁰ The combination of an insecticide and an insect growth regulator appears to be most effective in their synergistic actions against adult fleas and larvae. There have been reports of insecticidal resistance in the flea population, especially with pyrethroids.^21,22 A professional exterminator and veterinarian should be consulted. In recalcitrant cases, evaluation for other wild mammals or birds should be performed in unoccupied areas of the home such as the attic, crawl spaces, and basements, as well as inside walls.

 

Conclusion

The human flea, P irritans, is an important vector in the transmission of human diseases such as the bubonic plague, bartonellosis, and rickettsioses. Flea bites present as intensely pruritic, urticarial to vesicular papules that most commonly present on the lower extremities. Flea bites can be treated with topical steroids, and fleas can be controlled by a combination of insecticidal products and insect growth regulators.

A dult Siphonaptera (fleas) are highly adapted to life on the surface of their hosts. Their small 2- to 10-mm bodies are laterally flattened and wingless. They utilize particularly strong hind legs for jumping up to 150 times their body length and backward-directed spines on their legs and bodies for moving forward through fur, hair, and feathers. Xenopsylla cheopis , the oriental rat flea, lacks pronotal and genal combs and has a mesopleuron divided by internal scleritinization (Figure). These features differentiate the species from its close relatives, Ctenocephalides (cat and dog fleas), which have both sets of combs, as well as Pulex irritans (human flea), which do not have a divided mesopleuron. ^1,2

Flea-borne infections are extremely important to public health and are present throughout the world. Further, humidity and warmth are essential for the life cycle of many species of fleas. Predicted global warming likely will increase their distribution, allowing the spread of diseases they carry into previously untouched areas.¹ Therefore, it is important to continue to examine species that carry particularly dangerous pathogens, such as X cheopis.

Disease Vector

Xenopsylla cheopis primarily is known for being a vector in the transmission of Yersinia pestis, the etiologic agent of the plague. Plague occurs in 3 forms: bubonic, pneumonic, and septicemic. It has caused major epidemics throughout history, the most widely known being the Black Death, which lasted for 130 years, beginning in the 1330s in China and spreading into Europe where it wiped out one-third of the population. However, bubonic plague is thought to have caused documented outbreaks as early as 320 bce, and it still remains endemic today.^3,4

Between January 2010 and December 2015, 3248 cases of plague in humans were reported, resulting in 584 deaths worldwide.⁵ It is thought that the plague originated in Central Asia, and this area still is a focus of disease. However, the at-risk population is reduced to breeders and hunters of gerbils and marmots, the main reservoirs in the area. In Africa, 4 countries still regularly report cases, with Madagascar being the most severely affected country in the world.⁵ The Democratic Republic of the Congo, Uganda, and Tanzania also are affected. The Americas also experience the plague. There are sporadic cases of bubonic plague in the northwest corner of Peru, mostly in rural areas. In the western United States, plague circulates among wild rodents, resulting in several reported cases each year, with the most recent confirmed case noted in California in August 2020.^5,6 Further adding to its relevance, Y pestis is one of several organisms most likely to be used as a biologic weapon.^3,4

Due to the historical and continued significance of Y pestis, many studies have been performed over the decades regarding its association with X cheopis. It has been discovered that fleas transmit the bacteria to the host in 2 ways. The most well-defined form of transmission occurs after an incubation period of Y pestis in the flea for 7 to 31 days. During this time, the bacteria form a dense biofilm on a valve in the flea foregut—the proventriculus—interfering with its function, which allows regurgitation of the blood and the bacteria it contains into the bite site and consequently disease transmission. The proventriculus can become completely blocked in some fleas, preventing any blood from reaching the midgut and causing starvation. In these scenarios, the flea will make continuous attempts to feed, increasing transmission.⁷ The hemin storage gene, hms, encoding the second messenger molecule cyclic di-GMP plays a critical role in biofilm formation and proventricular blockage.⁸ The phosphoheptose isomerase gene, GmhA, also has been elucidated as crucial in late transmission due to its role in biofilm formation.⁹ Early-phase transmission, or biofilm-independent transmission, has been documented to occur as early as 3 hours after infection of the flea but can occur for up to 4 days.¹⁰ Historically, the importance of early-phase transmission has been overlooked. Research has shown that it likely is crucial to the epizootic transmission of the plague.¹⁰ As a result, the search has begun for genes that contribute to the maintenance of Y pestis in the flea vector during the first 4 days of colonization. It is thought that a key evolutionary development was the selective loss-of-function mutation in a gene essential for the activity of urease, an enzyme that causes acute oral toxicity and mortality in fleas.^11,12 The Yersinia murine toxin gene, Ymt, also allows for early survival of Y pestis in the flea midgut by producing a phospholipase D that protects the bacteria from toxic by-products produced during digestion of blood.^11,13 In addition, gene products that function in lipid A modification are crucial for the ability of Y pestis to resist the action of cationic antimicrobial peptides it produces, such as cecropin A and polymyxin B.¹³

Murine typhus, an acute febrile illness caused by Rickettsia typhi, is another disease that can be spread by oriental rat fleas. It has a worldwide distribution. In the United States, R typhi–induced rickettsia mainly is concentrated in suburban areas of Texas and California where it is thought to be mainly spread by Ctenocephalides, but it also is found in Hawaii where spread by X cheopis has been documented.^14,15 The most common symptoms of rickettsia include fever, headache, arthralgia, and a characteristic rash that is pruritic and maculopapular, starting on the trunk and spreading peripherally but sparing the palms and soles. This rash occurs about a week after the onset of fever.¹⁴Rickettsia felis also has been isolated in the oriental rat flea. However, only a handful of cases of human disease caused by this bacterium have been reported throughout the world, with clinical similarity to murine typhus likely leading to underestimation of disease prevalence.¹⁵Bartonella and other species of bacteria also have been documented to be spread by X cheopis.¹⁶ Unfortunately, the interactions of X cheopis with these other bacteria are not as well studied as its relationship with Y pestis.

Adverse Reactions

A flea bite itself can cause discomfort. It begins as a punctate hemorrhagic area that develops a surrounding wheal within 30 minutes. Over the course of 1 to 2 days, a delayed reaction occurs and there is a transition to an extremely pruritic, papular lesion. Bites often occur in clusters and can persist for weeks.¹

Prevention and Treatment

Control of host animals via extermination and proper sanitation can secondarily reduce the population of X cheopis. Direct pesticide control of the flea population also has been suggested to reduce flea-borne disease. However, insecticides cause a selective pressure on the flea population, leading to populations that are resistant to them. For example, the flea population in Madagascar developed resistance to DDT (dichlorodiphenyltrichloroethane), dieldrin, deltamethrin, and cyfluthrin after their widespread use.¹⁷ Further, a recent study revealed resistance of X cheopis populations to alphacypermethrin, lambda-cyhalothrin, and etofenprox, none of which were used in mass vector control, indicating that some cross-resistance mechanism between these and the extensively used insecticides may exist. With the development of widespread resistance to most pesticides, flea control in endemic areas is difficult. Insecticide targeting to fleas on rodents (eg, rodent bait containing insecticide) can allow for more targeted insecticide treatment, limiting the development of resistance.¹⁷ Recent development of a maceration protocol used to detect zoonotic pathogens in fleas in the field also will allow management with pesticides to be targeted geographically and temporally where infected vectors are located.¹⁸ Research of the interaction between vector, pathogen, and insect microbiome also should continue, as it may allow for development of biopesticides, limiting the use of chemical pesticides all together. The strategy is based on the introduction of microorganisms that can reduce vector lifespan or their ability to transmit pathogens.¹⁷

When flea-transmitted diseases do occur, treatment with antibiotics is advised. Early treatment of the plague with effective antibiotics such as streptomycin, gentamicin, tetracycline, or chloramphenicol for a minimum of 10 days is critical for survival. Additionally, patients with bubonic plague should be isolated for at least 2 days after administration of antibiotics, while patients with the pneumonic form should be isolated for 4 days into therapy to prevent the spread of disease. Prophylactic therapy for individuals who come into contact with infected individuals also is advised.⁴ Patients with murine typhus typically respond to doxycycline, tetracycline, or fluoroquinolones. The few cases of R felis–induced disease have responded to doxycycline. Of note, short courses of treatment of doxycycline are appropriate and safe in young children. The short (3–7 day) nature of the course limits the chances of teeth staining.¹⁴

A dult Siphonaptera (fleas) are highly adapted to life on the surface of their hosts. Their small 2- to 10-mm bodies are laterally flattened and wingless. They utilize particularly strong hind legs for jumping up to 150 times their body length and backward-directed spines on their legs and bodies for moving forward through fur, hair, and feathers. Xenopsylla cheopis , the oriental rat flea, lacks pronotal and genal combs and has a mesopleuron divided by internal scleritinization (Figure). These features differentiate the species from its close relatives, Ctenocephalides (cat and dog fleas), which have both sets of combs, as well as Pulex irritans (human flea), which do not have a divided mesopleuron. ^1,2

Flea-borne infections are extremely important to public health and are present throughout the world. Further, humidity and warmth are essential for the life cycle of many species of fleas. Predicted global warming likely will increase their distribution, allowing the spread of diseases they carry into previously untouched areas.¹ Therefore, it is important to continue to examine species that carry particularly dangerous pathogens, such as X cheopis.

Disease Vector

Xenopsylla cheopis primarily is known for being a vector in the transmission of Yersinia pestis, the etiologic agent of the plague. Plague occurs in 3 forms: bubonic, pneumonic, and septicemic. It has caused major epidemics throughout history, the most widely known being the Black Death, which lasted for 130 years, beginning in the 1330s in China and spreading into Europe where it wiped out one-third of the population. However, bubonic plague is thought to have caused documented outbreaks as early as 320 bce, and it still remains endemic today.^3,4

Between January 2010 and December 2015, 3248 cases of plague in humans were reported, resulting in 584 deaths worldwide.⁵ It is thought that the plague originated in Central Asia, and this area still is a focus of disease. However, the at-risk population is reduced to breeders and hunters of gerbils and marmots, the main reservoirs in the area. In Africa, 4 countries still regularly report cases, with Madagascar being the most severely affected country in the world.⁵ The Democratic Republic of the Congo, Uganda, and Tanzania also are affected. The Americas also experience the plague. There are sporadic cases of bubonic plague in the northwest corner of Peru, mostly in rural areas. In the western United States, plague circulates among wild rodents, resulting in several reported cases each year, with the most recent confirmed case noted in California in August 2020.^5,6 Further adding to its relevance, Y pestis is one of several organisms most likely to be used as a biologic weapon.^3,4

Due to the historical and continued significance of Y pestis, many studies have been performed over the decades regarding its association with X cheopis. It has been discovered that fleas transmit the bacteria to the host in 2 ways. The most well-defined form of transmission occurs after an incubation period of Y pestis in the flea for 7 to 31 days. During this time, the bacteria form a dense biofilm on a valve in the flea foregut—the proventriculus—interfering with its function, which allows regurgitation of the blood and the bacteria it contains into the bite site and consequently disease transmission. The proventriculus can become completely blocked in some fleas, preventing any blood from reaching the midgut and causing starvation. In these scenarios, the flea will make continuous attempts to feed, increasing transmission.⁷ The hemin storage gene, hms, encoding the second messenger molecule cyclic di-GMP plays a critical role in biofilm formation and proventricular blockage.⁸ The phosphoheptose isomerase gene, GmhA, also has been elucidated as crucial in late transmission due to its role in biofilm formation.⁹ Early-phase transmission, or biofilm-independent transmission, has been documented to occur as early as 3 hours after infection of the flea but can occur for up to 4 days.¹⁰ Historically, the importance of early-phase transmission has been overlooked. Research has shown that it likely is crucial to the epizootic transmission of the plague.¹⁰ As a result, the search has begun for genes that contribute to the maintenance of Y pestis in the flea vector during the first 4 days of colonization. It is thought that a key evolutionary development was the selective loss-of-function mutation in a gene essential for the activity of urease, an enzyme that causes acute oral toxicity and mortality in fleas.^11,12 The Yersinia murine toxin gene, Ymt, also allows for early survival of Y pestis in the flea midgut by producing a phospholipase D that protects the bacteria from toxic by-products produced during digestion of blood.^11,13 In addition, gene products that function in lipid A modification are crucial for the ability of Y pestis to resist the action of cationic antimicrobial peptides it produces, such as cecropin A and polymyxin B.¹³

Murine typhus, an acute febrile illness caused by Rickettsia typhi, is another disease that can be spread by oriental rat fleas. It has a worldwide distribution. In the United States, R typhi–induced rickettsia mainly is concentrated in suburban areas of Texas and California where it is thought to be mainly spread by Ctenocephalides, but it also is found in Hawaii where spread by X cheopis has been documented.^14,15 The most common symptoms of rickettsia include fever, headache, arthralgia, and a characteristic rash that is pruritic and maculopapular, starting on the trunk and spreading peripherally but sparing the palms and soles. This rash occurs about a week after the onset of fever.¹⁴Rickettsia felis also has been isolated in the oriental rat flea. However, only a handful of cases of human disease caused by this bacterium have been reported throughout the world, with clinical similarity to murine typhus likely leading to underestimation of disease prevalence.¹⁵Bartonella and other species of bacteria also have been documented to be spread by X cheopis.¹⁶ Unfortunately, the interactions of X cheopis with these other bacteria are not as well studied as its relationship with Y pestis.

Adverse Reactions

A flea bite itself can cause discomfort. It begins as a punctate hemorrhagic area that develops a surrounding wheal within 30 minutes. Over the course of 1 to 2 days, a delayed reaction occurs and there is a transition to an extremely pruritic, papular lesion. Bites often occur in clusters and can persist for weeks.¹

Prevention and Treatment

Control of host animals via extermination and proper sanitation can secondarily reduce the population of X cheopis. Direct pesticide control of the flea population also has been suggested to reduce flea-borne disease. However, insecticides cause a selective pressure on the flea population, leading to populations that are resistant to them. For example, the flea population in Madagascar developed resistance to DDT (dichlorodiphenyltrichloroethane), dieldrin, deltamethrin, and cyfluthrin after their widespread use.¹⁷ Further, a recent study revealed resistance of X cheopis populations to alphacypermethrin, lambda-cyhalothrin, and etofenprox, none of which were used in mass vector control, indicating that some cross-resistance mechanism between these and the extensively used insecticides may exist. With the development of widespread resistance to most pesticides, flea control in endemic areas is difficult. Insecticide targeting to fleas on rodents (eg, rodent bait containing insecticide) can allow for more targeted insecticide treatment, limiting the development of resistance.¹⁷ Recent development of a maceration protocol used to detect zoonotic pathogens in fleas in the field also will allow management with pesticides to be targeted geographically and temporally where infected vectors are located.¹⁸ Research of the interaction between vector, pathogen, and insect microbiome also should continue, as it may allow for development of biopesticides, limiting the use of chemical pesticides all together. The strategy is based on the introduction of microorganisms that can reduce vector lifespan or their ability to transmit pathogens.¹⁷

When flea-transmitted diseases do occur, treatment with antibiotics is advised. Early treatment of the plague with effective antibiotics such as streptomycin, gentamicin, tetracycline, or chloramphenicol for a minimum of 10 days is critical for survival. Additionally, patients with bubonic plague should be isolated for at least 2 days after administration of antibiotics, while patients with the pneumonic form should be isolated for 4 days into therapy to prevent the spread of disease. Prophylactic therapy for individuals who come into contact with infected individuals also is advised.⁴ Patients with murine typhus typically respond to doxycycline, tetracycline, or fluoroquinolones. The few cases of R felis–induced disease have responded to doxycycline. Of note, short courses of treatment of doxycycline are appropriate and safe in young children. The short (3–7 day) nature of the course limits the chances of teeth staining.¹⁴

A dult Siphonaptera (fleas) are highly adapted to life on the surface of their hosts. Their small 2- to 10-mm bodies are laterally flattened and wingless. They utilize particularly strong hind legs for jumping up to 150 times their body length and backward-directed spines on their legs and bodies for moving forward through fur, hair, and feathers. Xenopsylla cheopis , the oriental rat flea, lacks pronotal and genal combs and has a mesopleuron divided by internal scleritinization (Figure). These features differentiate the species from its close relatives, Ctenocephalides (cat and dog fleas), which have both sets of combs, as well as Pulex irritans (human flea), which do not have a divided mesopleuron. ^1,2

Flea-borne infections are extremely important to public health and are present throughout the world. Further, humidity and warmth are essential for the life cycle of many species of fleas. Predicted global warming likely will increase their distribution, allowing the spread of diseases they carry into previously untouched areas.¹ Therefore, it is important to continue to examine species that carry particularly dangerous pathogens, such as X cheopis.

Disease Vector

Xenopsylla cheopis primarily is known for being a vector in the transmission of Yersinia pestis, the etiologic agent of the plague. Plague occurs in 3 forms: bubonic, pneumonic, and septicemic. It has caused major epidemics throughout history, the most widely known being the Black Death, which lasted for 130 years, beginning in the 1330s in China and spreading into Europe where it wiped out one-third of the population. However, bubonic plague is thought to have caused documented outbreaks as early as 320 bce, and it still remains endemic today.^3,4

Between January 2010 and December 2015, 3248 cases of plague in humans were reported, resulting in 584 deaths worldwide.⁵ It is thought that the plague originated in Central Asia, and this area still is a focus of disease. However, the at-risk population is reduced to breeders and hunters of gerbils and marmots, the main reservoirs in the area. In Africa, 4 countries still regularly report cases, with Madagascar being the most severely affected country in the world.⁵ The Democratic Republic of the Congo, Uganda, and Tanzania also are affected. The Americas also experience the plague. There are sporadic cases of bubonic plague in the northwest corner of Peru, mostly in rural areas. In the western United States, plague circulates among wild rodents, resulting in several reported cases each year, with the most recent confirmed case noted in California in August 2020.^5,6 Further adding to its relevance, Y pestis is one of several organisms most likely to be used as a biologic weapon.^3,4

Due to the historical and continued significance of Y pestis, many studies have been performed over the decades regarding its association with X cheopis. It has been discovered that fleas transmit the bacteria to the host in 2 ways. The most well-defined form of transmission occurs after an incubation period of Y pestis in the flea for 7 to 31 days. During this time, the bacteria form a dense biofilm on a valve in the flea foregut—the proventriculus—interfering with its function, which allows regurgitation of the blood and the bacteria it contains into the bite site and consequently disease transmission. The proventriculus can become completely blocked in some fleas, preventing any blood from reaching the midgut and causing starvation. In these scenarios, the flea will make continuous attempts to feed, increasing transmission.⁷ The hemin storage gene, hms, encoding the second messenger molecule cyclic di-GMP plays a critical role in biofilm formation and proventricular blockage.⁸ The phosphoheptose isomerase gene, GmhA, also has been elucidated as crucial in late transmission due to its role in biofilm formation.⁹ Early-phase transmission, or biofilm-independent transmission, has been documented to occur as early as 3 hours after infection of the flea but can occur for up to 4 days.¹⁰ Historically, the importance of early-phase transmission has been overlooked. Research has shown that it likely is crucial to the epizootic transmission of the plague.¹⁰ As a result, the search has begun for genes that contribute to the maintenance of Y pestis in the flea vector during the first 4 days of colonization. It is thought that a key evolutionary development was the selective loss-of-function mutation in a gene essential for the activity of urease, an enzyme that causes acute oral toxicity and mortality in fleas.^11,12 The Yersinia murine toxin gene, Ymt, also allows for early survival of Y pestis in the flea midgut by producing a phospholipase D that protects the bacteria from toxic by-products produced during digestion of blood.^11,13 In addition, gene products that function in lipid A modification are crucial for the ability of Y pestis to resist the action of cationic antimicrobial peptides it produces, such as cecropin A and polymyxin B.¹³

Murine typhus, an acute febrile illness caused by Rickettsia typhi, is another disease that can be spread by oriental rat fleas. It has a worldwide distribution. In the United States, R typhi–induced rickettsia mainly is concentrated in suburban areas of Texas and California where it is thought to be mainly spread by Ctenocephalides, but it also is found in Hawaii where spread by X cheopis has been documented.^14,15 The most common symptoms of rickettsia include fever, headache, arthralgia, and a characteristic rash that is pruritic and maculopapular, starting on the trunk and spreading peripherally but sparing the palms and soles. This rash occurs about a week after the onset of fever.¹⁴Rickettsia felis also has been isolated in the oriental rat flea. However, only a handful of cases of human disease caused by this bacterium have been reported throughout the world, with clinical similarity to murine typhus likely leading to underestimation of disease prevalence.¹⁵Bartonella and other species of bacteria also have been documented to be spread by X cheopis.¹⁶ Unfortunately, the interactions of X cheopis with these other bacteria are not as well studied as its relationship with Y pestis.

Adverse Reactions

A flea bite itself can cause discomfort. It begins as a punctate hemorrhagic area that develops a surrounding wheal within 30 minutes. Over the course of 1 to 2 days, a delayed reaction occurs and there is a transition to an extremely pruritic, papular lesion. Bites often occur in clusters and can persist for weeks.¹

Prevention and Treatment

Control of host animals via extermination and proper sanitation can secondarily reduce the population of X cheopis. Direct pesticide control of the flea population also has been suggested to reduce flea-borne disease. However, insecticides cause a selective pressure on the flea population, leading to populations that are resistant to them. For example, the flea population in Madagascar developed resistance to DDT (dichlorodiphenyltrichloroethane), dieldrin, deltamethrin, and cyfluthrin after their widespread use.¹⁷ Further, a recent study revealed resistance of X cheopis populations to alphacypermethrin, lambda-cyhalothrin, and etofenprox, none of which were used in mass vector control, indicating that some cross-resistance mechanism between these and the extensively used insecticides may exist. With the development of widespread resistance to most pesticides, flea control in endemic areas is difficult. Insecticide targeting to fleas on rodents (eg, rodent bait containing insecticide) can allow for more targeted insecticide treatment, limiting the development of resistance.¹⁷ Recent development of a maceration protocol used to detect zoonotic pathogens in fleas in the field also will allow management with pesticides to be targeted geographically and temporally where infected vectors are located.¹⁸ Research of the interaction between vector, pathogen, and insect microbiome also should continue, as it may allow for development of biopesticides, limiting the use of chemical pesticides all together. The strategy is based on the introduction of microorganisms that can reduce vector lifespan or their ability to transmit pathogens.¹⁷

When flea-transmitted diseases do occur, treatment with antibiotics is advised. Early treatment of the plague with effective antibiotics such as streptomycin, gentamicin, tetracycline, or chloramphenicol for a minimum of 10 days is critical for survival. Additionally, patients with bubonic plague should be isolated for at least 2 days after administration of antibiotics, while patients with the pneumonic form should be isolated for 4 days into therapy to prevent the spread of disease. Prophylactic therapy for individuals who come into contact with infected individuals also is advised.⁴ Patients with murine typhus typically respond to doxycycline, tetracycline, or fluoroquinolones. The few cases of R felis–induced disease have responded to doxycycline. Of note, short courses of treatment of doxycycline are appropriate and safe in young children. The short (3–7 day) nature of the course limits the chances of teeth staining.¹⁴

Lepidoptera is the second largest order of the class Insecta and comprises approximately 160,000 species of butterflies and moths classified among approximately 124 families and subfamilies. Venomous properties have been identified in 12 of these families, posing a serious threat to human health. ¹

The clinical manifestations from Lepidoptera envenomation can range from general systemic symptoms such as fever and abdominal distress; to more complex focal affections including hemorrhage, ophthalmologic lesions, and irritation of the respiratory tracts; to less severe reactions of the skin, which are the most common presentation.¹

Terminology

Lepidopterism is the term used to address a clinical spectrum of systemic manifestations from direct contact with venomous butterflies or moths and/or their products.² Conversely, erucism is a term used to describe localized cutaneous reactions after direct contact with toxins from caterpillars.

Lepidopterism is derived from the Greek roots lepis, meaning scale, and pteron, meaning wing. The term erucism stems from the Latin word eruca, which means larva.²

Ideally, lepidopterism should refer solely to reactions from butterflies and moths—adult forms of insects with scaly wings—while erucism should refer to reactions from contact with caterpillars—the larval form of butterflies and moths.

In common use, lepidopterism can describe any reaction from caterpillars, moths, or adult butterflies, as well as any case of Lepidoptera exposure with only systemic manifestations, regardless of cutaneous findings. Concurrently, erucism has been defined as either any reaction from caterpillars or any skin reaction from contact with caterpillars or moths.²

Because caterpillars are the larval form of butterflies and moths, caterpillar-associated skin reactions also have been conveniently denominated caterpillar dermatitis.¹ Henceforth in this article, both terms erucism and caterpillar dermatitis are used interchangeably.

Caterpillar Envenomation

Caterpillars cause the vast majority of adverse events from lepidopteran exposures.² Envenomation by caterpillars might stand as the world’s most common envenomation given the larvae proximity to humans.³ Although involvement of internal organs (eg, renal failure), cerebral hemorrhage, and joint lesions can occur, skin manifestations are more predominant with the majority of species. Initial localized pain, edema, and erythema usually are present at the site of direct contact and subsequently progress toward maculopapular to bullous lesions, erosions, petechiae, necrosis, and ulceration depending on the offending species.^1,4

Megalopyge opercularis

In the United States, more than 50 species of caterpillars have been identified as poisonous or venomous.⁵ Megalopyge opercularis (Figure 1), the larval form of the flannel moth, is an important cause of caterpillar-associated dermatitis in the southern United States.^6,7 Megalopyge opercularis also is commonly known as the puss caterpillar, opossum bug, wooly slug, el perrito, tree asp, or Italian asp.⁶ This lepidopteran insect is mainly found in the southeastern and southcentral United States, with noted particular abundance in Texas, Louisiana, and Florida.^6,8 The puss caterpillar has 2 generations per year; the first develops during the months of June to July, and the second develops from September to October, carrying seasonal health hazards.^6,8

 

Megalopyge opercularis is tapered at the ends and can measure 2.5 to 3.5×1 cm at maturity. It is covered by silky, long-streaked, wavy hairs that may appear single colored or as a mix of colors—from white to gray to brown—forming a mid-dorsal crest.⁶ Beneath this furry coat, rows of short sharp spines are hidden. Upon contact with the human skin, these spines will break and discharge venom.^1,6,8 Toxins contained within the hollow spines are thought to be produced by specialized basal cells, but there still is little knowledge about the dynamics and composition of the venom.¹

Clinical Manifestations

The severity of the reaction depends on the caterpillar’s size and the extent of contact.^1,4 Contact with M opercularis instantly presents with a throbbing or burning pain that may be followed by localized erythema and rash.^1,6 A characteristic gridlike pattern of erythematous macules develops, reflecting each site of puncture from the insect’s spines (Figure 2).^8,9 Skin lesions can progress from erythematous macules to hemorrhagic vesicles or pustules, usually self-resolving after a few days. The reaction also can present with radiating pain to regional lymph nodes and numbness of the affected area.^1,6,8 Moreover, some patients may report urticaria and pruritus.⁹

Envenomation by a puss caterpillar also can present with systemic manifestations including fever, headache, nausea, vomiting, shocklike symptoms, and seizures.^1,6,7 Anaphylactic reaction is rare but also can present.⁷ Uncommon cases have been reported with severe abdominal pain and muscle spasm mimicking acute appendicitis and latrodectism, respectively.^7,9

Diagnosis

The diagnosis of M opercularis envenomation is made clinically based on the morphology of the skin lesions and a history of probable exposure. Coexistent leukocytosis is likely, but laboratory testing is not warranted, as it is both nonspecific and insensitive.⁹

Management/Treatment

The most commonly reported immediate approaches to treatment involve attempts to remove the spines from the skin with tape (stripping), application of ice packs over the affected area, oral antihistamines, topical and intralesional anesthetics, regional nerve block, and oral analgesics.^6,9 There have been several cases detailing the successful use of parenteral calcium gluconate,^5,7 and diazepam has been used to treat severe muscle spasms. Anaphylactic reactions should be managed in a controlled monitored setting with subcutaneous epinephrine.⁷ Despite their common use, some data suggest that ice packs and mid- to high-potency topical steroids are ineffective.⁹

Incidence

From 2001 to 2005, a mean average of 94,552 annual cases of animal bites and stings were reported to poison control centers in the United States, of which 2094 were linked to caterpillars in this 5-year period.¹⁰ There were 3484 M opercularis caterpillar stings reported to the Texas Poison Center Network from 2000 to 2016.^5,6 Given their ability to sting throughout their life cycle, thousands of M opercularis caterpillar stings can occur each year.^1,6 Existing literature on M opercularis caterpillar stings mainly involves case reports with affections of the skin and oral mucosa, self-reported envenomation, and case studies.^5,6,8

Although multiple health concerns associated with caterpillar envenomation have been reported worldwide, the lack of official epidemiologic reports highly suggests that this problem remains underestimated. There also may be many unreported cases because certain reactions are mild or self-limited and can even go unnoticed.¹¹ Nonetheless, there is an evident rise of cases reported in the United States. According to the 2018 annual report of the American Association of Poison Control Centers, there were 2815 case mentions from caterpillar envenomation.¹²

In 1921 and 1952, some public schools in Texas were temporarily closed due to outbreaks of puss caterpillar–associated dermatitis.⁸ Similar outbreaks also have been reported in South Carolina, Virginia, and Oklahoma.⁹ Emerging data suggest that plant oil products and the pesticide cypermethrin may be helpful in controlling local infestations of the puss caterpillar.⁸

Lepidoptera is the second largest order of the class Insecta and comprises approximately 160,000 species of butterflies and moths classified among approximately 124 families and subfamilies. Venomous properties have been identified in 12 of these families, posing a serious threat to human health. ¹

The clinical manifestations from Lepidoptera envenomation can range from general systemic symptoms such as fever and abdominal distress; to more complex focal affections including hemorrhage, ophthalmologic lesions, and irritation of the respiratory tracts; to less severe reactions of the skin, which are the most common presentation.¹

Terminology

Lepidopterism is the term used to address a clinical spectrum of systemic manifestations from direct contact with venomous butterflies or moths and/or their products.² Conversely, erucism is a term used to describe localized cutaneous reactions after direct contact with toxins from caterpillars.

Lepidopterism is derived from the Greek roots lepis, meaning scale, and pteron, meaning wing. The term erucism stems from the Latin word eruca, which means larva.²

Ideally, lepidopterism should refer solely to reactions from butterflies and moths—adult forms of insects with scaly wings—while erucism should refer to reactions from contact with caterpillars—the larval form of butterflies and moths.

In common use, lepidopterism can describe any reaction from caterpillars, moths, or adult butterflies, as well as any case of Lepidoptera exposure with only systemic manifestations, regardless of cutaneous findings. Concurrently, erucism has been defined as either any reaction from caterpillars or any skin reaction from contact with caterpillars or moths.²

Because caterpillars are the larval form of butterflies and moths, caterpillar-associated skin reactions also have been conveniently denominated caterpillar dermatitis.¹ Henceforth in this article, both terms erucism and caterpillar dermatitis are used interchangeably.

Caterpillar Envenomation

Caterpillars cause the vast majority of adverse events from lepidopteran exposures.² Envenomation by caterpillars might stand as the world’s most common envenomation given the larvae proximity to humans.³ Although involvement of internal organs (eg, renal failure), cerebral hemorrhage, and joint lesions can occur, skin manifestations are more predominant with the majority of species. Initial localized pain, edema, and erythema usually are present at the site of direct contact and subsequently progress toward maculopapular to bullous lesions, erosions, petechiae, necrosis, and ulceration depending on the offending species.^1,4

Megalopyge opercularis

In the United States, more than 50 species of caterpillars have been identified as poisonous or venomous.⁵ Megalopyge opercularis (Figure 1), the larval form of the flannel moth, is an important cause of caterpillar-associated dermatitis in the southern United States.^6,7 Megalopyge opercularis also is commonly known as the puss caterpillar, opossum bug, wooly slug, el perrito, tree asp, or Italian asp.⁶ This lepidopteran insect is mainly found in the southeastern and southcentral United States, with noted particular abundance in Texas, Louisiana, and Florida.^6,8 The puss caterpillar has 2 generations per year; the first develops during the months of June to July, and the second develops from September to October, carrying seasonal health hazards.^6,8

 

Megalopyge opercularis is tapered at the ends and can measure 2.5 to 3.5×1 cm at maturity. It is covered by silky, long-streaked, wavy hairs that may appear single colored or as a mix of colors—from white to gray to brown—forming a mid-dorsal crest.⁶ Beneath this furry coat, rows of short sharp spines are hidden. Upon contact with the human skin, these spines will break and discharge venom.^1,6,8 Toxins contained within the hollow spines are thought to be produced by specialized basal cells, but there still is little knowledge about the dynamics and composition of the venom.¹

Clinical Manifestations

The severity of the reaction depends on the caterpillar’s size and the extent of contact.^1,4 Contact with M opercularis instantly presents with a throbbing or burning pain that may be followed by localized erythema and rash.^1,6 A characteristic gridlike pattern of erythematous macules develops, reflecting each site of puncture from the insect’s spines (Figure 2).^8,9 Skin lesions can progress from erythematous macules to hemorrhagic vesicles or pustules, usually self-resolving after a few days. The reaction also can present with radiating pain to regional lymph nodes and numbness of the affected area.^1,6,8 Moreover, some patients may report urticaria and pruritus.⁹

Envenomation by a puss caterpillar also can present with systemic manifestations including fever, headache, nausea, vomiting, shocklike symptoms, and seizures.^1,6,7 Anaphylactic reaction is rare but also can present.⁷ Uncommon cases have been reported with severe abdominal pain and muscle spasm mimicking acute appendicitis and latrodectism, respectively.^7,9

Diagnosis

The diagnosis of M opercularis envenomation is made clinically based on the morphology of the skin lesions and a history of probable exposure. Coexistent leukocytosis is likely, but laboratory testing is not warranted, as it is both nonspecific and insensitive.⁹

Management/Treatment

The most commonly reported immediate approaches to treatment involve attempts to remove the spines from the skin with tape (stripping), application of ice packs over the affected area, oral antihistamines, topical and intralesional anesthetics, regional nerve block, and oral analgesics.^6,9 There have been several cases detailing the successful use of parenteral calcium gluconate,^5,7 and diazepam has been used to treat severe muscle spasms. Anaphylactic reactions should be managed in a controlled monitored setting with subcutaneous epinephrine.⁷ Despite their common use, some data suggest that ice packs and mid- to high-potency topical steroids are ineffective.⁹

Incidence

From 2001 to 2005, a mean average of 94,552 annual cases of animal bites and stings were reported to poison control centers in the United States, of which 2094 were linked to caterpillars in this 5-year period.¹⁰ There were 3484 M opercularis caterpillar stings reported to the Texas Poison Center Network from 2000 to 2016.^5,6 Given their ability to sting throughout their life cycle, thousands of M opercularis caterpillar stings can occur each year.^1,6 Existing literature on M opercularis caterpillar stings mainly involves case reports with affections of the skin and oral mucosa, self-reported envenomation, and case studies.^5,6,8

Although multiple health concerns associated with caterpillar envenomation have been reported worldwide, the lack of official epidemiologic reports highly suggests that this problem remains underestimated. There also may be many unreported cases because certain reactions are mild or self-limited and can even go unnoticed.¹¹ Nonetheless, there is an evident rise of cases reported in the United States. According to the 2018 annual report of the American Association of Poison Control Centers, there were 2815 case mentions from caterpillar envenomation.¹²

In 1921 and 1952, some public schools in Texas were temporarily closed due to outbreaks of puss caterpillar–associated dermatitis.⁸ Similar outbreaks also have been reported in South Carolina, Virginia, and Oklahoma.⁹ Emerging data suggest that plant oil products and the pesticide cypermethrin may be helpful in controlling local infestations of the puss caterpillar.⁸

Lepidoptera is the second largest order of the class Insecta and comprises approximately 160,000 species of butterflies and moths classified among approximately 124 families and subfamilies. Venomous properties have been identified in 12 of these families, posing a serious threat to human health. ¹

The clinical manifestations from Lepidoptera envenomation can range from general systemic symptoms such as fever and abdominal distress; to more complex focal affections including hemorrhage, ophthalmologic lesions, and irritation of the respiratory tracts; to less severe reactions of the skin, which are the most common presentation.¹

Terminology

Lepidopterism is the term used to address a clinical spectrum of systemic manifestations from direct contact with venomous butterflies or moths and/or their products.² Conversely, erucism is a term used to describe localized cutaneous reactions after direct contact with toxins from caterpillars.

Lepidopterism is derived from the Greek roots lepis, meaning scale, and pteron, meaning wing. The term erucism stems from the Latin word eruca, which means larva.²

Ideally, lepidopterism should refer solely to reactions from butterflies and moths—adult forms of insects with scaly wings—while erucism should refer to reactions from contact with caterpillars—the larval form of butterflies and moths.

In common use, lepidopterism can describe any reaction from caterpillars, moths, or adult butterflies, as well as any case of Lepidoptera exposure with only systemic manifestations, regardless of cutaneous findings. Concurrently, erucism has been defined as either any reaction from caterpillars or any skin reaction from contact with caterpillars or moths.²

Because caterpillars are the larval form of butterflies and moths, caterpillar-associated skin reactions also have been conveniently denominated caterpillar dermatitis.¹ Henceforth in this article, both terms erucism and caterpillar dermatitis are used interchangeably.

Caterpillar Envenomation

Caterpillars cause the vast majority of adverse events from lepidopteran exposures.² Envenomation by caterpillars might stand as the world’s most common envenomation given the larvae proximity to humans.³ Although involvement of internal organs (eg, renal failure), cerebral hemorrhage, and joint lesions can occur, skin manifestations are more predominant with the majority of species. Initial localized pain, edema, and erythema usually are present at the site of direct contact and subsequently progress toward maculopapular to bullous lesions, erosions, petechiae, necrosis, and ulceration depending on the offending species.^1,4

Megalopyge opercularis

In the United States, more than 50 species of caterpillars have been identified as poisonous or venomous.⁵ Megalopyge opercularis (Figure 1), the larval form of the flannel moth, is an important cause of caterpillar-associated dermatitis in the southern United States.^6,7 Megalopyge opercularis also is commonly known as the puss caterpillar, opossum bug, wooly slug, el perrito, tree asp, or Italian asp.⁶ This lepidopteran insect is mainly found in the southeastern and southcentral United States, with noted particular abundance in Texas, Louisiana, and Florida.^6,8 The puss caterpillar has 2 generations per year; the first develops during the months of June to July, and the second develops from September to October, carrying seasonal health hazards.^6,8

 

Megalopyge opercularis is tapered at the ends and can measure 2.5 to 3.5×1 cm at maturity. It is covered by silky, long-streaked, wavy hairs that may appear single colored or as a mix of colors—from white to gray to brown—forming a mid-dorsal crest.⁶ Beneath this furry coat, rows of short sharp spines are hidden. Upon contact with the human skin, these spines will break and discharge venom.^1,6,8 Toxins contained within the hollow spines are thought to be produced by specialized basal cells, but there still is little knowledge about the dynamics and composition of the venom.¹

Clinical Manifestations

The severity of the reaction depends on the caterpillar’s size and the extent of contact.^1,4 Contact with M opercularis instantly presents with a throbbing or burning pain that may be followed by localized erythema and rash.^1,6 A characteristic gridlike pattern of erythematous macules develops, reflecting each site of puncture from the insect’s spines (Figure 2).^8,9 Skin lesions can progress from erythematous macules to hemorrhagic vesicles or pustules, usually self-resolving after a few days. The reaction also can present with radiating pain to regional lymph nodes and numbness of the affected area.^1,6,8 Moreover, some patients may report urticaria and pruritus.⁹

Envenomation by a puss caterpillar also can present with systemic manifestations including fever, headache, nausea, vomiting, shocklike symptoms, and seizures.^1,6,7 Anaphylactic reaction is rare but also can present.⁷ Uncommon cases have been reported with severe abdominal pain and muscle spasm mimicking acute appendicitis and latrodectism, respectively.^7,9

Diagnosis

The diagnosis of M opercularis envenomation is made clinically based on the morphology of the skin lesions and a history of probable exposure. Coexistent leukocytosis is likely, but laboratory testing is not warranted, as it is both nonspecific and insensitive.⁹

Management/Treatment

The most commonly reported immediate approaches to treatment involve attempts to remove the spines from the skin with tape (stripping), application of ice packs over the affected area, oral antihistamines, topical and intralesional anesthetics, regional nerve block, and oral analgesics.^6,9 There have been several cases detailing the successful use of parenteral calcium gluconate,^5,7 and diazepam has been used to treat severe muscle spasms. Anaphylactic reactions should be managed in a controlled monitored setting with subcutaneous epinephrine.⁷ Despite their common use, some data suggest that ice packs and mid- to high-potency topical steroids are ineffective.⁹

Incidence

From 2001 to 2005, a mean average of 94,552 annual cases of animal bites and stings were reported to poison control centers in the United States, of which 2094 were linked to caterpillars in this 5-year period.¹⁰ There were 3484 M opercularis caterpillar stings reported to the Texas Poison Center Network from 2000 to 2016.^5,6 Given their ability to sting throughout their life cycle, thousands of M opercularis caterpillar stings can occur each year.^1,6 Existing literature on M opercularis caterpillar stings mainly involves case reports with affections of the skin and oral mucosa, self-reported envenomation, and case studies.^5,6,8

Although multiple health concerns associated with caterpillar envenomation have been reported worldwide, the lack of official epidemiologic reports highly suggests that this problem remains underestimated. There also may be many unreported cases because certain reactions are mild or self-limited and can even go unnoticed.¹¹ Nonetheless, there is an evident rise of cases reported in the United States. According to the 2018 annual report of the American Association of Poison Control Centers, there were 2815 case mentions from caterpillar envenomation.¹²

In 1921 and 1952, some public schools in Texas were temporarily closed due to outbreaks of puss caterpillar–associated dermatitis.⁸ Similar outbreaks also have been reported in South Carolina, Virginia, and Oklahoma.⁹ Emerging data suggest that plant oil products and the pesticide cypermethrin may be helpful in controlling local infestations of the puss caterpillar.⁸