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The Diagnosis: Heparin-Induced Bullous Hemorrhagic Dermatosis

Results of a punch biopsy of one of the hemorrhagic papules revealed a subcorneal hemorrhagic vesicle without underlying vasculitis, vasculopathy, inflammation, or viral changes (Figure). Tissue and blood cultures were sterile. Heparin and platelet factor 4 antibody testing was negative. The patient was diagnosed with heparin induced bullous hemorrhagic dermatosis (BHD). After chest imaging ruled out a pulmonary embolism, anticoagulation therapy was discontinued. Respiratory symptoms improved on antibiotics, and the skin lesions resolved completely within 2 weeks.

Bullous hemorrhagic dermatosis is an uncommon and underrecognized reaction to various anticoagulants. Bullous hemorrhagic dermatosis presents with painless, noninflammatory, hemorrhagic vesicles and bullae occurring at sites distant from anticoagulant administration. The condition was first characterized in 2006 by Perrinaud et al,¹ who presented 3 cases in patients treated with heparin and low-molecular-weight heparin. Since then, there have been at least 90 cases reported in the international literature, with elderly men found to be the more affected demographic (male to female ratio, 1.9:1).² Typically, BHD presents within 1 week of administration of an anticoagulant, but delayed onset has been reported.² Bullous hemorrhagic dermatosis is most commonly observed with enoxaparin use but also has been described in association with unfractionated heparin, low-molecular-weight heparin products, and warfarin.²

The noninflammatory-appearing hemorrhagic papules and small plaques of BHD generally are seen on the extremities but can occur anywhere on the body including the oral mucosa.³ The differential diagnosis of BHD may include autoimmune vesiculobullous conditions, bullous drug eruptions, herpetic infection, supratherapeutic anticoagulation, porphyria cutanea tarda, amyloidosis, leukocytoclastic vasculitis, angioinvasive infections, and heparin necrosis. Diagnosis of BHD can be made clinically, but a biopsy is useful to exclude other conditions.

Histologically, BHD is characterized by the presence of intraepidermal hemorrhagic bullae without thrombotic, inflammatory, or vasculitic changes. Although heparinrelated skin lesions have been attributed to various mechanisms, including immune-mediated thrombocytopenia, type IV hypersensitivity reactions, type I allergic hypersensitivity reactions, pustulosis, and skin necrosis, the pathogenesis of BHD remains poorly understood.⁴ The condition has demonstrated koebnerization in some cases.⁵

In our patient, the absence of histologic inflammation, viral changes, vasculitis, and amyloid deposition helped rule out the other entities in the differential. The absence of heparin and platelet factor 4 antibodies helped exclude heparin necrosis. Direct immunofluorescence testing was not obtained in our patient but may be used to evaluate for an immunobullous etiology.

Management strategies for BHD are variable, and associated evidence is lacking. Treatment of BHD should be considered in the clinical context based on the necessity for anticoagulation and the severity of the eruption. Discontinuation of anticoagulation therapy, if possible, may prevent morbidity in some cases.⁶ If it is necessary to continue anticoagulation therapy, changing the drug or decreasing the dose are reasonable options. Skin lesions may resolve even if anticoagulation therapy is continued at the same dose.^7,8 Concurrent supportive wound care is beneficial.

The Diagnosis: Heparin-Induced Bullous Hemorrhagic Dermatosis

Results of a punch biopsy of one of the hemorrhagic papules revealed a subcorneal hemorrhagic vesicle without underlying vasculitis, vasculopathy, inflammation, or viral changes (Figure). Tissue and blood cultures were sterile. Heparin and platelet factor 4 antibody testing was negative. The patient was diagnosed with heparin induced bullous hemorrhagic dermatosis (BHD). After chest imaging ruled out a pulmonary embolism, anticoagulation therapy was discontinued. Respiratory symptoms improved on antibiotics, and the skin lesions resolved completely within 2 weeks.

Bullous hemorrhagic dermatosis is an uncommon and underrecognized reaction to various anticoagulants. Bullous hemorrhagic dermatosis presents with painless, noninflammatory, hemorrhagic vesicles and bullae occurring at sites distant from anticoagulant administration. The condition was first characterized in 2006 by Perrinaud et al,¹ who presented 3 cases in patients treated with heparin and low-molecular-weight heparin. Since then, there have been at least 90 cases reported in the international literature, with elderly men found to be the more affected demographic (male to female ratio, 1.9:1).² Typically, BHD presents within 1 week of administration of an anticoagulant, but delayed onset has been reported.² Bullous hemorrhagic dermatosis is most commonly observed with enoxaparin use but also has been described in association with unfractionated heparin, low-molecular-weight heparin products, and warfarin.²

The noninflammatory-appearing hemorrhagic papules and small plaques of BHD generally are seen on the extremities but can occur anywhere on the body including the oral mucosa.³ The differential diagnosis of BHD may include autoimmune vesiculobullous conditions, bullous drug eruptions, herpetic infection, supratherapeutic anticoagulation, porphyria cutanea tarda, amyloidosis, leukocytoclastic vasculitis, angioinvasive infections, and heparin necrosis. Diagnosis of BHD can be made clinically, but a biopsy is useful to exclude other conditions.

Histologically, BHD is characterized by the presence of intraepidermal hemorrhagic bullae without thrombotic, inflammatory, or vasculitic changes. Although heparinrelated skin lesions have been attributed to various mechanisms, including immune-mediated thrombocytopenia, type IV hypersensitivity reactions, type I allergic hypersensitivity reactions, pustulosis, and skin necrosis, the pathogenesis of BHD remains poorly understood.⁴ The condition has demonstrated koebnerization in some cases.⁵

In our patient, the absence of histologic inflammation, viral changes, vasculitis, and amyloid deposition helped rule out the other entities in the differential. The absence of heparin and platelet factor 4 antibodies helped exclude heparin necrosis. Direct immunofluorescence testing was not obtained in our patient but may be used to evaluate for an immunobullous etiology.

Management strategies for BHD are variable, and associated evidence is lacking. Treatment of BHD should be considered in the clinical context based on the necessity for anticoagulation and the severity of the eruption. Discontinuation of anticoagulation therapy, if possible, may prevent morbidity in some cases.⁶ If it is necessary to continue anticoagulation therapy, changing the drug or decreasing the dose are reasonable options. Skin lesions may resolve even if anticoagulation therapy is continued at the same dose.^7,8 Concurrent supportive wound care is beneficial.

The Diagnosis: Heparin-Induced Bullous Hemorrhagic Dermatosis

Results of a punch biopsy of one of the hemorrhagic papules revealed a subcorneal hemorrhagic vesicle without underlying vasculitis, vasculopathy, inflammation, or viral changes (Figure). Tissue and blood cultures were sterile. Heparin and platelet factor 4 antibody testing was negative. The patient was diagnosed with heparin induced bullous hemorrhagic dermatosis (BHD). After chest imaging ruled out a pulmonary embolism, anticoagulation therapy was discontinued. Respiratory symptoms improved on antibiotics, and the skin lesions resolved completely within 2 weeks.

Bullous hemorrhagic dermatosis is an uncommon and underrecognized reaction to various anticoagulants. Bullous hemorrhagic dermatosis presents with painless, noninflammatory, hemorrhagic vesicles and bullae occurring at sites distant from anticoagulant administration. The condition was first characterized in 2006 by Perrinaud et al,¹ who presented 3 cases in patients treated with heparin and low-molecular-weight heparin. Since then, there have been at least 90 cases reported in the international literature, with elderly men found to be the more affected demographic (male to female ratio, 1.9:1).² Typically, BHD presents within 1 week of administration of an anticoagulant, but delayed onset has been reported.² Bullous hemorrhagic dermatosis is most commonly observed with enoxaparin use but also has been described in association with unfractionated heparin, low-molecular-weight heparin products, and warfarin.²

The noninflammatory-appearing hemorrhagic papules and small plaques of BHD generally are seen on the extremities but can occur anywhere on the body including the oral mucosa.³ The differential diagnosis of BHD may include autoimmune vesiculobullous conditions, bullous drug eruptions, herpetic infection, supratherapeutic anticoagulation, porphyria cutanea tarda, amyloidosis, leukocytoclastic vasculitis, angioinvasive infections, and heparin necrosis. Diagnosis of BHD can be made clinically, but a biopsy is useful to exclude other conditions.

Histologically, BHD is characterized by the presence of intraepidermal hemorrhagic bullae without thrombotic, inflammatory, or vasculitic changes. Although heparinrelated skin lesions have been attributed to various mechanisms, including immune-mediated thrombocytopenia, type IV hypersensitivity reactions, type I allergic hypersensitivity reactions, pustulosis, and skin necrosis, the pathogenesis of BHD remains poorly understood.⁴ The condition has demonstrated koebnerization in some cases.⁵

In our patient, the absence of histologic inflammation, viral changes, vasculitis, and amyloid deposition helped rule out the other entities in the differential. The absence of heparin and platelet factor 4 antibodies helped exclude heparin necrosis. Direct immunofluorescence testing was not obtained in our patient but may be used to evaluate for an immunobullous etiology.

Management strategies for BHD are variable, and associated evidence is lacking. Treatment of BHD should be considered in the clinical context based on the necessity for anticoagulation and the severity of the eruption. Discontinuation of anticoagulation therapy, if possible, may prevent morbidity in some cases.⁶ If it is necessary to continue anticoagulation therapy, changing the drug or decreasing the dose are reasonable options. Skin lesions may resolve even if anticoagulation therapy is continued at the same dose.^7,8 Concurrent supportive wound care is beneficial.

The Diagnosis: Relapsing Polychondritis 

Due to suspicion of relapsing polychondritis (RP), we also performed an audiometric evaluation, which demonstrated bilateral sensorineural hearing loss. Echocardiography highlighted mild to moderate mitralic and tricuspidal insufficiency without hemodynamic impairment (ejection fraction, 50%). Corticosteroid therapy was started (prednisone 0.5 mg/kg/d). After 7 days of treatment, inflammation was remarkably reduced, and the patient no longer reported pain. 

Relapsing polychondritis is a rare noninfective condition characterized by focal inflammatory destruction of ear cartilage, followed by fibroblastic regeneration. It often is associated with ocular inflammation, including conjunctivitis, scleritis, and episcleritis; cochlear or vestibular lesions; and seronegative nonerosive inflammatory arthritis.¹ Clinical examination of the affected area shows swelling, redness, and tenderness of the ear, which could lead to a misdiagnosis of cellulitis. A typical and useful differentiating sign is the sparing of the noncartilaginous parts of the ear lobule. If not promptly diagnosed and treated, the destructive process can cause thinning of the cartilage, leading to deformities of the external ear.  

The differential diagnosis includes erysipelas, which presents as a rapidly appearing inflammatory patch with sharply defined borders, accompanied by regional lymphadenopathy or skin streaking as well as fever. Sweet syndrome usually presents with tender erythematous or violaceous skin papules, plaques, or nodules, frequently with a pseudovesicular appearance; patients generally present with a classic fever and peripheral neutrophilia.² The localized cutaneous form of leishmaniasis usually appears with a papule that generally develops into an ulcerative nodular lesion. Our patient did not have a history of exposure to topical substances that could point to photocontact dermatitis.  

Dion et al³ proposed 3 distinct clinical phenotypes of RP: (1) patients with concomitant myelodysplastic syndrome or other hematologic malignancy (<10% of patients), mostly older men with a poor prognosis; (2) patients with tracheobronchial involvement (approximately 25% of patients); and (3) patients who do not have hematologic or tracheobronchial involvement (approximately 65% of patients) with a good prognosis.  

Two sets of diagnostic criteria have been proposed. The criteria from McAdam et al⁴ required the presence of 3 or more of the following clinical features: bilateral auricular chondritis, nonerosive seronegative inflammatory polyarthritis, nasal chondritis, ocular inflammation (eg, conjunctivitis, keratitis, scleritis/episcleritis, uveitis), respiratory tract chondritis (laryngeal and/or tracheal cartilages), and cochlear and/or vestibular dysfunction (eg, neurosensory hearing loss, tinnitus, vertigo). These criteria were modified by Damiani and Levine.⁵ According to the latter, all patients were required to have one of the following: at least 4 of the McAdam et al⁴ diagnostic criteria; 1 or more of the clinical findings included in the McAdam et al⁴ criteria with histologic features suggestive for RP; or chondritis at 2 or more separate anatomic locations with a response to glucocorticoids and/or dapsone.  

No laboratory findings are specific for RP, and nonspecific indicators of inflammation--elevated erythrocyte sedimentation rate and C-reactive protein--often are present. 
The cause of RP is unknown. Familial clustering has not been observed. Terao et al⁶ found that HLA-DRB1*1602, -DQB1*0502, and -B*6701, in linkage disequilibrium with each other, are associated with susceptibility to RP. 

There is no universal consensus about treatment, but a course of steroids leads to the resolution of the acute phase. Maintenance treatment can include dapsone, azathioprine, methotrexate, cyclophosphamide, and cyclosporine.^7,8 Some studies have described the successful use of anti-tumor necrosis factor α inhibitors and rituximab.^9,10  

The Diagnosis: Relapsing Polychondritis 

Due to suspicion of relapsing polychondritis (RP), we also performed an audiometric evaluation, which demonstrated bilateral sensorineural hearing loss. Echocardiography highlighted mild to moderate mitralic and tricuspidal insufficiency without hemodynamic impairment (ejection fraction, 50%). Corticosteroid therapy was started (prednisone 0.5 mg/kg/d). After 7 days of treatment, inflammation was remarkably reduced, and the patient no longer reported pain. 

Relapsing polychondritis is a rare noninfective condition characterized by focal inflammatory destruction of ear cartilage, followed by fibroblastic regeneration. It often is associated with ocular inflammation, including conjunctivitis, scleritis, and episcleritis; cochlear or vestibular lesions; and seronegative nonerosive inflammatory arthritis.¹ Clinical examination of the affected area shows swelling, redness, and tenderness of the ear, which could lead to a misdiagnosis of cellulitis. A typical and useful differentiating sign is the sparing of the noncartilaginous parts of the ear lobule. If not promptly diagnosed and treated, the destructive process can cause thinning of the cartilage, leading to deformities of the external ear.  

The differential diagnosis includes erysipelas, which presents as a rapidly appearing inflammatory patch with sharply defined borders, accompanied by regional lymphadenopathy or skin streaking as well as fever. Sweet syndrome usually presents with tender erythematous or violaceous skin papules, plaques, or nodules, frequently with a pseudovesicular appearance; patients generally present with a classic fever and peripheral neutrophilia.² The localized cutaneous form of leishmaniasis usually appears with a papule that generally develops into an ulcerative nodular lesion. Our patient did not have a history of exposure to topical substances that could point to photocontact dermatitis.  

Dion et al³ proposed 3 distinct clinical phenotypes of RP: (1) patients with concomitant myelodysplastic syndrome or other hematologic malignancy (<10% of patients), mostly older men with a poor prognosis; (2) patients with tracheobronchial involvement (approximately 25% of patients); and (3) patients who do not have hematologic or tracheobronchial involvement (approximately 65% of patients) with a good prognosis.  

Two sets of diagnostic criteria have been proposed. The criteria from McAdam et al⁴ required the presence of 3 or more of the following clinical features: bilateral auricular chondritis, nonerosive seronegative inflammatory polyarthritis, nasal chondritis, ocular inflammation (eg, conjunctivitis, keratitis, scleritis/episcleritis, uveitis), respiratory tract chondritis (laryngeal and/or tracheal cartilages), and cochlear and/or vestibular dysfunction (eg, neurosensory hearing loss, tinnitus, vertigo). These criteria were modified by Damiani and Levine.⁵ According to the latter, all patients were required to have one of the following: at least 4 of the McAdam et al⁴ diagnostic criteria; 1 or more of the clinical findings included in the McAdam et al⁴ criteria with histologic features suggestive for RP; or chondritis at 2 or more separate anatomic locations with a response to glucocorticoids and/or dapsone.  

No laboratory findings are specific for RP, and nonspecific indicators of inflammation--elevated erythrocyte sedimentation rate and C-reactive protein--often are present. 
The cause of RP is unknown. Familial clustering has not been observed. Terao et al⁶ found that HLA-DRB1*1602, -DQB1*0502, and -B*6701, in linkage disequilibrium with each other, are associated with susceptibility to RP. 

There is no universal consensus about treatment, but a course of steroids leads to the resolution of the acute phase. Maintenance treatment can include dapsone, azathioprine, methotrexate, cyclophosphamide, and cyclosporine.^7,8 Some studies have described the successful use of anti-tumor necrosis factor α inhibitors and rituximab.^9,10  

The Diagnosis: Relapsing Polychondritis 

Due to suspicion of relapsing polychondritis (RP), we also performed an audiometric evaluation, which demonstrated bilateral sensorineural hearing loss. Echocardiography highlighted mild to moderate mitralic and tricuspidal insufficiency without hemodynamic impairment (ejection fraction, 50%). Corticosteroid therapy was started (prednisone 0.5 mg/kg/d). After 7 days of treatment, inflammation was remarkably reduced, and the patient no longer reported pain. 

Relapsing polychondritis is a rare noninfective condition characterized by focal inflammatory destruction of ear cartilage, followed by fibroblastic regeneration. It often is associated with ocular inflammation, including conjunctivitis, scleritis, and episcleritis; cochlear or vestibular lesions; and seronegative nonerosive inflammatory arthritis.¹ Clinical examination of the affected area shows swelling, redness, and tenderness of the ear, which could lead to a misdiagnosis of cellulitis. A typical and useful differentiating sign is the sparing of the noncartilaginous parts of the ear lobule. If not promptly diagnosed and treated, the destructive process can cause thinning of the cartilage, leading to deformities of the external ear.  

The differential diagnosis includes erysipelas, which presents as a rapidly appearing inflammatory patch with sharply defined borders, accompanied by regional lymphadenopathy or skin streaking as well as fever. Sweet syndrome usually presents with tender erythematous or violaceous skin papules, plaques, or nodules, frequently with a pseudovesicular appearance; patients generally present with a classic fever and peripheral neutrophilia.² The localized cutaneous form of leishmaniasis usually appears with a papule that generally develops into an ulcerative nodular lesion. Our patient did not have a history of exposure to topical substances that could point to photocontact dermatitis.  

Dion et al³ proposed 3 distinct clinical phenotypes of RP: (1) patients with concomitant myelodysplastic syndrome or other hematologic malignancy (<10% of patients), mostly older men with a poor prognosis; (2) patients with tracheobronchial involvement (approximately 25% of patients); and (3) patients who do not have hematologic or tracheobronchial involvement (approximately 65% of patients) with a good prognosis.  

Two sets of diagnostic criteria have been proposed. The criteria from McAdam et al⁴ required the presence of 3 or more of the following clinical features: bilateral auricular chondritis, nonerosive seronegative inflammatory polyarthritis, nasal chondritis, ocular inflammation (eg, conjunctivitis, keratitis, scleritis/episcleritis, uveitis), respiratory tract chondritis (laryngeal and/or tracheal cartilages), and cochlear and/or vestibular dysfunction (eg, neurosensory hearing loss, tinnitus, vertigo). These criteria were modified by Damiani and Levine.⁵ According to the latter, all patients were required to have one of the following: at least 4 of the McAdam et al⁴ diagnostic criteria; 1 or more of the clinical findings included in the McAdam et al⁴ criteria with histologic features suggestive for RP; or chondritis at 2 or more separate anatomic locations with a response to glucocorticoids and/or dapsone.  

No laboratory findings are specific for RP, and nonspecific indicators of inflammation--elevated erythrocyte sedimentation rate and C-reactive protein--often are present. 
The cause of RP is unknown. Familial clustering has not been observed. Terao et al⁶ found that HLA-DRB1*1602, -DQB1*0502, and -B*6701, in linkage disequilibrium with each other, are associated with susceptibility to RP. 

There is no universal consensus about treatment, but a course of steroids leads to the resolution of the acute phase. Maintenance treatment can include dapsone, azathioprine, methotrexate, cyclophosphamide, and cyclosporine.^7,8 Some studies have described the successful use of anti-tumor necrosis factor α inhibitors and rituximab.^9,10  

The Diagnosis: Acrodermatitis Enteropathica 

Acrodermatitis enteropathica (AE) was the presumptive diagnosis. Oral supplementation with zinc sulfate 3 mg/kg/d was started immediately after a zinc level was ordered. A low zinc level of 15 µg/dL (reference range, 56-134 µg/dL) eventually was obtained. The lesions began to fade in 2 days along with return of normal feeding and disposition, and the patient was discharged with continued zinc supplementation.  

Acrodermatitis enteropathica is an autosomal-recessive condition resulting in severe zinc deficiency caused by a defect of dietary zinc absorption in the duodenum and jejunum.¹ It occurs in 1 in 500,000 individuals with no gender or racial predilection. It can be acquired or inherited.² Recognition of clinical symptoms is essential due to potential death if untreated. Zinc is an important trace element required for the proper functioning of all cells and plays a large role in the metabolism of protein, carbohydrates, and vitamin A. Zinc deficiency impairs immune function, leading to bacterial infections. It also is a cofactor of numerous metal enzymes such as alkaline phosphatase, RNA polymerase, and numerous digestive enzymes.³  

Our laboratory analysis revealed low alkaline phosphatase and zinc levels, which led to the diagnosis of AE; unfortunately, these levels can be ambiguous.⁴ There are many causes of acquired zinc deficiency, including premature birth, low birth weight, zinc deficiency in maternal milk, exclusive parenteral nutrition, malabsorption syndromes such as Crohn disease and celiac disease, alcoholism, low calcium and phytate (cereal grain) diet, and kwashiorkor.⁵ The hereditary deficiency of zinc classically is known as AE and is caused by an autosomal-recessive mutation of the SLC39A4 gene on chromosome arm 8q24.3, which determines a congenital partial or total deficiency of the zinc transporter protein ZIP4.⁶  

The clinical manifestations of acquired zinc deficiency and AE are similar and consist of 3 essential symptoms: periorificial dermatitis, alopecia, and diarrhea. Unfortunately, this clinical triad is complete in only 20% of patients with AE.³ For example, our patient was too young for an alopecia determination. The disease typically presents with eczematous papules and sometimes vesiculobullous or pustular lesions located around perioral and acral areas (Figure 1) as well as the anogenital region (Figures 2 and 3). The severity of the skin lesions is variable.⁷ Our patient also presented with eczematous truncal papules on the chest (Figure 4). Acrodermatitis enteropathica usually presents during childhood after weaning. Along with the aforementioned skin findings, other symptoms in infancy can include diarrhea, mood changes, and anorexia. In school-aged children and toddlers, zinc deficiency is characterized by growth retardation, alopecia, weight loss, and recurrent infections.  

In the differential diagnosis, the clinical presentation of biotin deficiency involves abnormalities of the hair, skin, nails, and central nervous system (eg, seizures, ataxia, deafness).⁸ Cystic fibrosis presentation depends on the multiorgan involvement, but neonates often present with failure to thrive.⁹ Essential fatty acid deficiency presents clinically as dermatitis, alopecia, and thrombocytopenia, but a complete blood cell count with platelets was within reference range in our patient.¹⁰ Langerhans cell histiocytosis presents with perineal and postauricular lesions, but the skin biopsy did not confirm this diagnosis in our patient.¹¹ Histopathologic examination of the buttock biopsy in our patient revealed nonspecific epidermal hyperplasia with acanthosis as well as clustered necrotic keratinocytes with vacuolization and parakeratosis.  

Most clinicians who suspect AE treat with a therapeutic supplementation of zinc sulfate 3 mg/kg/d while awaiting laboratory results. Acrodermatitis enteropathica is a rare condition, and early recognition of skin findings is important because misdiagnosis can lead to infections, malnutrition, and possibly death.  

The Diagnosis: Acrodermatitis Enteropathica 

Acrodermatitis enteropathica (AE) was the presumptive diagnosis. Oral supplementation with zinc sulfate 3 mg/kg/d was started immediately after a zinc level was ordered. A low zinc level of 15 µg/dL (reference range, 56-134 µg/dL) eventually was obtained. The lesions began to fade in 2 days along with return of normal feeding and disposition, and the patient was discharged with continued zinc supplementation.  

Acrodermatitis enteropathica is an autosomal-recessive condition resulting in severe zinc deficiency caused by a defect of dietary zinc absorption in the duodenum and jejunum.¹ It occurs in 1 in 500,000 individuals with no gender or racial predilection. It can be acquired or inherited.² Recognition of clinical symptoms is essential due to potential death if untreated. Zinc is an important trace element required for the proper functioning of all cells and plays a large role in the metabolism of protein, carbohydrates, and vitamin A. Zinc deficiency impairs immune function, leading to bacterial infections. It also is a cofactor of numerous metal enzymes such as alkaline phosphatase, RNA polymerase, and numerous digestive enzymes.³  

Our laboratory analysis revealed low alkaline phosphatase and zinc levels, which led to the diagnosis of AE; unfortunately, these levels can be ambiguous.⁴ There are many causes of acquired zinc deficiency, including premature birth, low birth weight, zinc deficiency in maternal milk, exclusive parenteral nutrition, malabsorption syndromes such as Crohn disease and celiac disease, alcoholism, low calcium and phytate (cereal grain) diet, and kwashiorkor.⁵ The hereditary deficiency of zinc classically is known as AE and is caused by an autosomal-recessive mutation of the SLC39A4 gene on chromosome arm 8q24.3, which determines a congenital partial or total deficiency of the zinc transporter protein ZIP4.⁶  

The clinical manifestations of acquired zinc deficiency and AE are similar and consist of 3 essential symptoms: periorificial dermatitis, alopecia, and diarrhea. Unfortunately, this clinical triad is complete in only 20% of patients with AE.³ For example, our patient was too young for an alopecia determination. The disease typically presents with eczematous papules and sometimes vesiculobullous or pustular lesions located around perioral and acral areas (Figure 1) as well as the anogenital region (Figures 2 and 3). The severity of the skin lesions is variable.⁷ Our patient also presented with eczematous truncal papules on the chest (Figure 4). Acrodermatitis enteropathica usually presents during childhood after weaning. Along with the aforementioned skin findings, other symptoms in infancy can include diarrhea, mood changes, and anorexia. In school-aged children and toddlers, zinc deficiency is characterized by growth retardation, alopecia, weight loss, and recurrent infections.  

In the differential diagnosis, the clinical presentation of biotin deficiency involves abnormalities of the hair, skin, nails, and central nervous system (eg, seizures, ataxia, deafness).⁸ Cystic fibrosis presentation depends on the multiorgan involvement, but neonates often present with failure to thrive.⁹ Essential fatty acid deficiency presents clinically as dermatitis, alopecia, and thrombocytopenia, but a complete blood cell count with platelets was within reference range in our patient.¹⁰ Langerhans cell histiocytosis presents with perineal and postauricular lesions, but the skin biopsy did not confirm this diagnosis in our patient.¹¹ Histopathologic examination of the buttock biopsy in our patient revealed nonspecific epidermal hyperplasia with acanthosis as well as clustered necrotic keratinocytes with vacuolization and parakeratosis.  

Most clinicians who suspect AE treat with a therapeutic supplementation of zinc sulfate 3 mg/kg/d while awaiting laboratory results. Acrodermatitis enteropathica is a rare condition, and early recognition of skin findings is important because misdiagnosis can lead to infections, malnutrition, and possibly death.  

The Diagnosis: Acrodermatitis Enteropathica 

Acrodermatitis enteropathica (AE) was the presumptive diagnosis. Oral supplementation with zinc sulfate 3 mg/kg/d was started immediately after a zinc level was ordered. A low zinc level of 15 µg/dL (reference range, 56-134 µg/dL) eventually was obtained. The lesions began to fade in 2 days along with return of normal feeding and disposition, and the patient was discharged with continued zinc supplementation.  

Acrodermatitis enteropathica is an autosomal-recessive condition resulting in severe zinc deficiency caused by a defect of dietary zinc absorption in the duodenum and jejunum.¹ It occurs in 1 in 500,000 individuals with no gender or racial predilection. It can be acquired or inherited.² Recognition of clinical symptoms is essential due to potential death if untreated. Zinc is an important trace element required for the proper functioning of all cells and plays a large role in the metabolism of protein, carbohydrates, and vitamin A. Zinc deficiency impairs immune function, leading to bacterial infections. It also is a cofactor of numerous metal enzymes such as alkaline phosphatase, RNA polymerase, and numerous digestive enzymes.³  

Our laboratory analysis revealed low alkaline phosphatase and zinc levels, which led to the diagnosis of AE; unfortunately, these levels can be ambiguous.⁴ There are many causes of acquired zinc deficiency, including premature birth, low birth weight, zinc deficiency in maternal milk, exclusive parenteral nutrition, malabsorption syndromes such as Crohn disease and celiac disease, alcoholism, low calcium and phytate (cereal grain) diet, and kwashiorkor.⁵ The hereditary deficiency of zinc classically is known as AE and is caused by an autosomal-recessive mutation of the SLC39A4 gene on chromosome arm 8q24.3, which determines a congenital partial or total deficiency of the zinc transporter protein ZIP4.⁶  

The clinical manifestations of acquired zinc deficiency and AE are similar and consist of 3 essential symptoms: periorificial dermatitis, alopecia, and diarrhea. Unfortunately, this clinical triad is complete in only 20% of patients with AE.³ For example, our patient was too young for an alopecia determination. The disease typically presents with eczematous papules and sometimes vesiculobullous or pustular lesions located around perioral and acral areas (Figure 1) as well as the anogenital region (Figures 2 and 3). The severity of the skin lesions is variable.⁷ Our patient also presented with eczematous truncal papules on the chest (Figure 4). Acrodermatitis enteropathica usually presents during childhood after weaning. Along with the aforementioned skin findings, other symptoms in infancy can include diarrhea, mood changes, and anorexia. In school-aged children and toddlers, zinc deficiency is characterized by growth retardation, alopecia, weight loss, and recurrent infections.  

In the differential diagnosis, the clinical presentation of biotin deficiency involves abnormalities of the hair, skin, nails, and central nervous system (eg, seizures, ataxia, deafness).⁸ Cystic fibrosis presentation depends on the multiorgan involvement, but neonates often present with failure to thrive.⁹ Essential fatty acid deficiency presents clinically as dermatitis, alopecia, and thrombocytopenia, but a complete blood cell count with platelets was within reference range in our patient.¹⁰ Langerhans cell histiocytosis presents with perineal and postauricular lesions, but the skin biopsy did not confirm this diagnosis in our patient.¹¹ Histopathologic examination of the buttock biopsy in our patient revealed nonspecific epidermal hyperplasia with acanthosis as well as clustered necrotic keratinocytes with vacuolization and parakeratosis.  

Most clinicians who suspect AE treat with a therapeutic supplementation of zinc sulfate 3 mg/kg/d while awaiting laboratory results. Acrodermatitis enteropathica is a rare condition, and early recognition of skin findings is important because misdiagnosis can lead to infections, malnutrition, and possibly death.  

The Diagnosis: Fusariosis 

A periodic acid-Schiff stain of the seropurulent drainage from a skin nodule revealed neutrophils and scarce branching hyaline hyphae. Skin and blood cultures grew a white cottony colony. Microscopic examination showed sickle-shaped macroconidia and septate hyaline hyphae with branching acute angles (Figure). Molecular analysis by polymerase chain reaction yielded Fusarium solani species complex. Histopathology as well as culture and molecular findings were consistent with a diagnosis of disseminated fusariosis. Amphotericin B was started with rapid clinical improvement. The patient was asymptomatic upon discharge with voriconazole 200 mg twice daily. 

Fusariosis is an emerging, opportunistic, and life-threatening mycosis. In immunocompetent patients it may cause onychomycosis and keratitis.¹ Invasive fusariosis predominantly is caused by the F solani species complex and affects immunocompromised patients, especially those with neutropenia or acute leukemia or hematopoietic stem cell transplant recipients.² 

Before invasion, the infection frequently may begin by affecting the nail apparatus as onychomycosis or paronychia of the skin. As in our case, trauma or manipulation of the nail favors dissemination.³ Skin manifestations include erythematous to violaceous papules, macules, and nodules with central necrosis or crust; some may exhibit target morphology. Other organs may be affected, including the sinuses, lungs, liver, spleen, and kidneys. A comprehensive clinical examination before hematopoietic cell transplant and during fever and neutropenia may opportunely identify these potential infective foci.^3,4 

The differential diagnosis of disseminated fusariosis includes bacterial infections, especially Staphylococcus aureus and Pseudomonas aeruginosa, and other invasive fungal infections, particularly aspergillosis, mucormycosis, and candidiasis.⁵ Symptom persistence after broad-spectrum antibiotic initiation should raise diagnostic suspicion of systemic mycosis or mycobacterial infection. Mucormycosis and candidiasis have histopathologic profiles that differ from fusariosis, presenting with broad ribbonlike hyphae with 90° angulation and pseudohyphae with budding yeast cells, respectively. Differentiation of disseminated fusariosis and aspergillosis in neutropenic patients is difficult. Hyphae cannot be differentiated from those of Aspergillus species on histology.⁶ Furthermore, serologic assays, such as galactomannan and (1,3)-β-D-glucan, cross-react with both genera. Clinically, Fusarium species exhibit metastatic skin lesions, cellulitis, and positive blood cultures due to adventitious sporulation more frequently than Aspergillus species. Patients with aspergillosis more commonly present with sinusitis, pneumonia, and pulmonary macronodules with the halo sign.⁶ Although nocardiosis presents with disseminated subcutaneous nodules with pulmonary affection in immunocompromised patients, its morphology is very different from fusariosis. Nocardia presents with a gram-positive bacillus with the microscopic appearance of branching filaments. Yeastlike microorganisms with morphology ranging from oval to sausagelike are found in talaromycosis, an uncommon fungal infection predominantly caused by Talaromyces marneffei. Fusarium species culture reveals white cottony colonies with characteristic hyaline, canoe-shaped or sickle-shaped (banana-shaped), multicellular macroconidia, and microconidia. Precise species identification requires molecular analyses such as polymerase chain reaction. 

Mortality is high, ranging from 50% to 70% of cases.⁵ Voriconazole or lipid-based amphotericin B are considered first-line treatments. Posaconazole may be employed as a second-line alternative. Surgical debridement of infected tissues and removal of colonized venous catheters is recommended. Secondary prophylaxis should be considered with agents such as voriconazole, posaconazole, or amphotericin B.⁵ Resolution of immunosuppression and neutropenia is an important factor to reduce the mortality rate. 

The Diagnosis: Fusariosis 

A periodic acid-Schiff stain of the seropurulent drainage from a skin nodule revealed neutrophils and scarce branching hyaline hyphae. Skin and blood cultures grew a white cottony colony. Microscopic examination showed sickle-shaped macroconidia and septate hyaline hyphae with branching acute angles (Figure). Molecular analysis by polymerase chain reaction yielded Fusarium solani species complex. Histopathology as well as culture and molecular findings were consistent with a diagnosis of disseminated fusariosis. Amphotericin B was started with rapid clinical improvement. The patient was asymptomatic upon discharge with voriconazole 200 mg twice daily. 

Fusariosis is an emerging, opportunistic, and life-threatening mycosis. In immunocompetent patients it may cause onychomycosis and keratitis.¹ Invasive fusariosis predominantly is caused by the F solani species complex and affects immunocompromised patients, especially those with neutropenia or acute leukemia or hematopoietic stem cell transplant recipients.² 

Before invasion, the infection frequently may begin by affecting the nail apparatus as onychomycosis or paronychia of the skin. As in our case, trauma or manipulation of the nail favors dissemination.³ Skin manifestations include erythematous to violaceous papules, macules, and nodules with central necrosis or crust; some may exhibit target morphology. Other organs may be affected, including the sinuses, lungs, liver, spleen, and kidneys. A comprehensive clinical examination before hematopoietic cell transplant and during fever and neutropenia may opportunely identify these potential infective foci.^3,4 

The differential diagnosis of disseminated fusariosis includes bacterial infections, especially Staphylococcus aureus and Pseudomonas aeruginosa, and other invasive fungal infections, particularly aspergillosis, mucormycosis, and candidiasis.⁵ Symptom persistence after broad-spectrum antibiotic initiation should raise diagnostic suspicion of systemic mycosis or mycobacterial infection. Mucormycosis and candidiasis have histopathologic profiles that differ from fusariosis, presenting with broad ribbonlike hyphae with 90° angulation and pseudohyphae with budding yeast cells, respectively. Differentiation of disseminated fusariosis and aspergillosis in neutropenic patients is difficult. Hyphae cannot be differentiated from those of Aspergillus species on histology.⁶ Furthermore, serologic assays, such as galactomannan and (1,3)-β-D-glucan, cross-react with both genera. Clinically, Fusarium species exhibit metastatic skin lesions, cellulitis, and positive blood cultures due to adventitious sporulation more frequently than Aspergillus species. Patients with aspergillosis more commonly present with sinusitis, pneumonia, and pulmonary macronodules with the halo sign.⁶ Although nocardiosis presents with disseminated subcutaneous nodules with pulmonary affection in immunocompromised patients, its morphology is very different from fusariosis. Nocardia presents with a gram-positive bacillus with the microscopic appearance of branching filaments. Yeastlike microorganisms with morphology ranging from oval to sausagelike are found in talaromycosis, an uncommon fungal infection predominantly caused by Talaromyces marneffei. Fusarium species culture reveals white cottony colonies with characteristic hyaline, canoe-shaped or sickle-shaped (banana-shaped), multicellular macroconidia, and microconidia. Precise species identification requires molecular analyses such as polymerase chain reaction. 

Mortality is high, ranging from 50% to 70% of cases.⁵ Voriconazole or lipid-based amphotericin B are considered first-line treatments. Posaconazole may be employed as a second-line alternative. Surgical debridement of infected tissues and removal of colonized venous catheters is recommended. Secondary prophylaxis should be considered with agents such as voriconazole, posaconazole, or amphotericin B.⁵ Resolution of immunosuppression and neutropenia is an important factor to reduce the mortality rate. 

The Diagnosis: Fusariosis 

A periodic acid-Schiff stain of the seropurulent drainage from a skin nodule revealed neutrophils and scarce branching hyaline hyphae. Skin and blood cultures grew a white cottony colony. Microscopic examination showed sickle-shaped macroconidia and septate hyaline hyphae with branching acute angles (Figure). Molecular analysis by polymerase chain reaction yielded Fusarium solani species complex. Histopathology as well as culture and molecular findings were consistent with a diagnosis of disseminated fusariosis. Amphotericin B was started with rapid clinical improvement. The patient was asymptomatic upon discharge with voriconazole 200 mg twice daily. 

Fusariosis is an emerging, opportunistic, and life-threatening mycosis. In immunocompetent patients it may cause onychomycosis and keratitis.¹ Invasive fusariosis predominantly is caused by the F solani species complex and affects immunocompromised patients, especially those with neutropenia or acute leukemia or hematopoietic stem cell transplant recipients.² 

Before invasion, the infection frequently may begin by affecting the nail apparatus as onychomycosis or paronychia of the skin. As in our case, trauma or manipulation of the nail favors dissemination.³ Skin manifestations include erythematous to violaceous papules, macules, and nodules with central necrosis or crust; some may exhibit target morphology. Other organs may be affected, including the sinuses, lungs, liver, spleen, and kidneys. A comprehensive clinical examination before hematopoietic cell transplant and during fever and neutropenia may opportunely identify these potential infective foci.^3,4 

The differential diagnosis of disseminated fusariosis includes bacterial infections, especially Staphylococcus aureus and Pseudomonas aeruginosa, and other invasive fungal infections, particularly aspergillosis, mucormycosis, and candidiasis.⁵ Symptom persistence after broad-spectrum antibiotic initiation should raise diagnostic suspicion of systemic mycosis or mycobacterial infection. Mucormycosis and candidiasis have histopathologic profiles that differ from fusariosis, presenting with broad ribbonlike hyphae with 90° angulation and pseudohyphae with budding yeast cells, respectively. Differentiation of disseminated fusariosis and aspergillosis in neutropenic patients is difficult. Hyphae cannot be differentiated from those of Aspergillus species on histology.⁶ Furthermore, serologic assays, such as galactomannan and (1,3)-β-D-glucan, cross-react with both genera. Clinically, Fusarium species exhibit metastatic skin lesions, cellulitis, and positive blood cultures due to adventitious sporulation more frequently than Aspergillus species. Patients with aspergillosis more commonly present with sinusitis, pneumonia, and pulmonary macronodules with the halo sign.⁶ Although nocardiosis presents with disseminated subcutaneous nodules with pulmonary affection in immunocompromised patients, its morphology is very different from fusariosis. Nocardia presents with a gram-positive bacillus with the microscopic appearance of branching filaments. Yeastlike microorganisms with morphology ranging from oval to sausagelike are found in talaromycosis, an uncommon fungal infection predominantly caused by Talaromyces marneffei. Fusarium species culture reveals white cottony colonies with characteristic hyaline, canoe-shaped or sickle-shaped (banana-shaped), multicellular macroconidia, and microconidia. Precise species identification requires molecular analyses such as polymerase chain reaction. 

Mortality is high, ranging from 50% to 70% of cases.⁵ Voriconazole or lipid-based amphotericin B are considered first-line treatments. Posaconazole may be employed as a second-line alternative. Surgical debridement of infected tissues and removal of colonized venous catheters is recommended. Secondary prophylaxis should be considered with agents such as voriconazole, posaconazole, or amphotericin B.⁵ Resolution of immunosuppression and neutropenia is an important factor to reduce the mortality rate. 

The Diagnosis: Foreign Body Reaction With Sinus Tract  

A delayed foreign body reaction is a rare complication of retained temporary pacing wires following cardiovascular surgery. These epicardial pacing wires are important for the management of postoperative arrhythmia and normally are removed by external traction after normal rhythm has been re-established. However, it is not uncommon for these wires to be cut at the skin surface in the setting of difficult removal, as retained pacing wires generally are viewed as benign.¹ These reactions often take years after placement of the pacing wire to present themselves and most often resolve with either complete removal of the wire or resection of the distal end.²  

Our patient was referred to dermatology and underwent a shave biopsy. Results were consistent with chronic inflammatory granulation tissue. Bacterial tissue culture grew Staphylococcus epidermidis. Cultures for acid-fast bacilli and fungi were negative. The patient was referred to cardiothoracic surgery. Computed tomography identified a retained temporary pacing wire extending to the base of the lesion. The lesion was excised and the distal aspect of the pacing wire was removed, which resulted in resolution of the nodule.  

The differential diagnosis includes pyoderma gangrenosum, nodular basal cell carcinoma, Sister Mary Joseph nodule, and pyogenic granuloma. Pyoderma gangrenosum is a neutrophilic dermatosis that presents as a rapidly progressing, painful, necrotic ulcer. It is classically associated with inflammatory bowel disease and other systemic diseases but also can occur in isolation.³  

Nodular basal cell carcinomas often develop in chronically sun-exposed areas of the body. Morphologically, they present as pink, pearl appearing papules with rolled borders and overlying arborizing telangiectasia. Nodular basal cell carcinomas may present with recurrent bleeding but typically do not have continuous drainage.⁴  

Sister Mary Joseph nodule represents a periumbilical lymphatic metastasis from an underlying (usually intra-abdominal) malignancy. It typically presents as an umbilical or periumbilical nodule measuring 0.5 to 15 cm in diameter. The nodules often are painful and discharge a serous fluid. It is estimated that they are present in 1% to 3% of cases of abdominopelvic malignancy, but Sister Mary Joseph nodules also have been reported in several other types of solid organ tumors.⁵  

Pyogenic granuloma is a benign vascular lesion that classically develops rapidly over the course of a few weeks. It often presents as a single red, moist, friable papule with a collarette of scale and frequently is associated with pain, bleeding, and ulceration. Keratinized skin or mucosa can be affected, and pyogenic granuloma is most common in children and young adults.⁶  

The Diagnosis: Foreign Body Reaction With Sinus Tract  

A delayed foreign body reaction is a rare complication of retained temporary pacing wires following cardiovascular surgery. These epicardial pacing wires are important for the management of postoperative arrhythmia and normally are removed by external traction after normal rhythm has been re-established. However, it is not uncommon for these wires to be cut at the skin surface in the setting of difficult removal, as retained pacing wires generally are viewed as benign.¹ These reactions often take years after placement of the pacing wire to present themselves and most often resolve with either complete removal of the wire or resection of the distal end.²  

Our patient was referred to dermatology and underwent a shave biopsy. Results were consistent with chronic inflammatory granulation tissue. Bacterial tissue culture grew Staphylococcus epidermidis. Cultures for acid-fast bacilli and fungi were negative. The patient was referred to cardiothoracic surgery. Computed tomography identified a retained temporary pacing wire extending to the base of the lesion. The lesion was excised and the distal aspect of the pacing wire was removed, which resulted in resolution of the nodule.  

The differential diagnosis includes pyoderma gangrenosum, nodular basal cell carcinoma, Sister Mary Joseph nodule, and pyogenic granuloma. Pyoderma gangrenosum is a neutrophilic dermatosis that presents as a rapidly progressing, painful, necrotic ulcer. It is classically associated with inflammatory bowel disease and other systemic diseases but also can occur in isolation.³  

Nodular basal cell carcinomas often develop in chronically sun-exposed areas of the body. Morphologically, they present as pink, pearl appearing papules with rolled borders and overlying arborizing telangiectasia. Nodular basal cell carcinomas may present with recurrent bleeding but typically do not have continuous drainage.⁴  

Sister Mary Joseph nodule represents a periumbilical lymphatic metastasis from an underlying (usually intra-abdominal) malignancy. It typically presents as an umbilical or periumbilical nodule measuring 0.5 to 15 cm in diameter. The nodules often are painful and discharge a serous fluid. It is estimated that they are present in 1% to 3% of cases of abdominopelvic malignancy, but Sister Mary Joseph nodules also have been reported in several other types of solid organ tumors.⁵  

Pyogenic granuloma is a benign vascular lesion that classically develops rapidly over the course of a few weeks. It often presents as a single red, moist, friable papule with a collarette of scale and frequently is associated with pain, bleeding, and ulceration. Keratinized skin or mucosa can be affected, and pyogenic granuloma is most common in children and young adults.⁶  

The Diagnosis: Foreign Body Reaction With Sinus Tract  

A delayed foreign body reaction is a rare complication of retained temporary pacing wires following cardiovascular surgery. These epicardial pacing wires are important for the management of postoperative arrhythmia and normally are removed by external traction after normal rhythm has been re-established. However, it is not uncommon for these wires to be cut at the skin surface in the setting of difficult removal, as retained pacing wires generally are viewed as benign.¹ These reactions often take years after placement of the pacing wire to present themselves and most often resolve with either complete removal of the wire or resection of the distal end.²  

Our patient was referred to dermatology and underwent a shave biopsy. Results were consistent with chronic inflammatory granulation tissue. Bacterial tissue culture grew Staphylococcus epidermidis. Cultures for acid-fast bacilli and fungi were negative. The patient was referred to cardiothoracic surgery. Computed tomography identified a retained temporary pacing wire extending to the base of the lesion. The lesion was excised and the distal aspect of the pacing wire was removed, which resulted in resolution of the nodule.  

The differential diagnosis includes pyoderma gangrenosum, nodular basal cell carcinoma, Sister Mary Joseph nodule, and pyogenic granuloma. Pyoderma gangrenosum is a neutrophilic dermatosis that presents as a rapidly progressing, painful, necrotic ulcer. It is classically associated with inflammatory bowel disease and other systemic diseases but also can occur in isolation.³  

Nodular basal cell carcinomas often develop in chronically sun-exposed areas of the body. Morphologically, they present as pink, pearl appearing papules with rolled borders and overlying arborizing telangiectasia. Nodular basal cell carcinomas may present with recurrent bleeding but typically do not have continuous drainage.⁴  

Sister Mary Joseph nodule represents a periumbilical lymphatic metastasis from an underlying (usually intra-abdominal) malignancy. It typically presents as an umbilical or periumbilical nodule measuring 0.5 to 15 cm in diameter. The nodules often are painful and discharge a serous fluid. It is estimated that they are present in 1% to 3% of cases of abdominopelvic malignancy, but Sister Mary Joseph nodules also have been reported in several other types of solid organ tumors.⁵  

Pyogenic granuloma is a benign vascular lesion that classically develops rapidly over the course of a few weeks. It often presents as a single red, moist, friable papule with a collarette of scale and frequently is associated with pain, bleeding, and ulceration. Keratinized skin or mucosa can be affected, and pyogenic granuloma is most common in children and young adults.⁶  

The Diagnosis: Onychodystrophy Secondary to Polydactyly

Radiographs of the feet demonstrated an accessory distal phalanx of the left great toe with a similar smaller accessory distal phalanx on the right great toe (Figure). The patient was referred to orthopedic surgery, and surgical intervention was recommended for only the left great toe given recurrent skin inflammation and nail complications. An excision of the left great toe polydactyly was performed. The patient healed well without complications.

Many clinically heterogeneous phenotypes exist for polydactyly and syndactyly, which both are common entities with incidences of 1 in 700 to 1000 births and 1 in 2000 to 3000 births, respectively.¹ Both polydactyly and syndactyly can be an isolated variant in newborns or present with multiple concurrent malformations as part of a genetic syndrome, with more than 300 syndromic anomalies described. The genetic basis of these conditions is equally diverse, with homeobox genes, hedgehog pathways, fibroblast growth factors, and boneand cartilage-derived morphogenetic proteins implicated in their development.¹

The differential diagnosis for our patient included congenital malalignment of the great toenails, nail-patella syndrome, onychodystrophy secondary to polydactyly, and congenital hypertrophy of the lateral nail fold. Given the strong family history, polydactyly was suspected.

Congenital malalignment of the great toenails results in lateral deviation of the nail plates.² It is an underdiagnosed condition with different etiologies hypothesized, such as genetic factors with possible autosomal-dominant transmission and extrinsic factors.³ One proposed mechanism of pathogenesis is desynchronization during growth of the nail and distal phalanx of the hallux, leading to larger nail plates that grow laterally.⁴ Typical features associated with this disease are nail discoloration, nail plate thickening, and transversal grooves or ridges, none of which were seen in our patient.²

Children with nail-patella syndrome have dysplastic nails and associated bony abnormalities, such as absent patellae.⁵ This syndrome results from an autosomaldominant mutation in the LIM homeobox transcription factor 1-beta gene, LMX1B, which is responsible for dorsal-ventral patterning of the limb, as well as patterning of the nails, patellae and long bones, and even the kidney tubule.⁶ As such, patients with nail-patella syndrome have associated renal abnormalities. The findings in our patient were limited to the feet, making an underlying syndrome unlikely to be the cause.

First described in 1968 by Meadow,⁷ fetal hydantoin syndrome is a well-documented sequela in women taking phenytoin throughout pregnancy. Multiple malformations are possible, including cardiac defects, cleft lip/palate, digit and nail hypoplasia, abnormal facial features, mental disability, and growth abnormalities.⁸ The teratogenicity behind phenytoin results from reactive oxygen species that alter embryonic DNA, proteins, and lipids.⁹ The mother of this child was not on any seizure prophylaxis, eliminating it from the differential.

Congenital hypertrophy of the lateral nail fold is a defect of the soft tissue of the hallux leading to hypertrophy of the nail fold, commonly presenting with inflammation and pain¹⁰ possibly due to dyssynchronous growth between the soft tissue and nail plate.¹¹ With this defect, a lip covering the nail plate is common, which was not seen in our patient.

As demonstrated in our patient, family history can help guide the diagnosis. Seven of 9 nonsyndromic forms of syndactyly are inherited in an autosomal-dominant fashion and range from mild presentations, as in our patient, to more severe deformations with underlying bone fusion and functional impairment.¹² Polydactyly also often is expressed in an autosomal-dominant pattern, with up to 30% of patients having a positive family history. Polydactyly traditionally is classified by the location of the supernumerary digit as preaxial (radial), central, or postaxial (ulnar), and many further morphologic variations exist within these groups. Overall, preaxial polydactyly is relatively rare and represents 15% of polydactylies, with central and postaxial comprising the other 6% and 79%, respectively.¹³ Delineation of the underlying anatomy may reveal ray duplications (digit and corresponding metacarpal or metatarsal bone), metatarsal variants, and duplicated phalanges that may be hypoplastic or deformed. Patients may report difficulty finding comfortable footwear, cosmetic concerns, and nail-related complications. Although not always required, surgical intervention may provide definitive treatment but can leave residual deformities in the surrounding altered anatomy; thus, orthopedic or plastic surgery consultations are critical in appropriately counseling patients.

The Diagnosis: Onychodystrophy Secondary to Polydactyly

Radiographs of the feet demonstrated an accessory distal phalanx of the left great toe with a similar smaller accessory distal phalanx on the right great toe (Figure). The patient was referred to orthopedic surgery, and surgical intervention was recommended for only the left great toe given recurrent skin inflammation and nail complications. An excision of the left great toe polydactyly was performed. The patient healed well without complications.

Many clinically heterogeneous phenotypes exist for polydactyly and syndactyly, which both are common entities with incidences of 1 in 700 to 1000 births and 1 in 2000 to 3000 births, respectively.¹ Both polydactyly and syndactyly can be an isolated variant in newborns or present with multiple concurrent malformations as part of a genetic syndrome, with more than 300 syndromic anomalies described. The genetic basis of these conditions is equally diverse, with homeobox genes, hedgehog pathways, fibroblast growth factors, and boneand cartilage-derived morphogenetic proteins implicated in their development.¹

The differential diagnosis for our patient included congenital malalignment of the great toenails, nail-patella syndrome, onychodystrophy secondary to polydactyly, and congenital hypertrophy of the lateral nail fold. Given the strong family history, polydactyly was suspected.

Congenital malalignment of the great toenails results in lateral deviation of the nail plates.² It is an underdiagnosed condition with different etiologies hypothesized, such as genetic factors with possible autosomal-dominant transmission and extrinsic factors.³ One proposed mechanism of pathogenesis is desynchronization during growth of the nail and distal phalanx of the hallux, leading to larger nail plates that grow laterally.⁴ Typical features associated with this disease are nail discoloration, nail plate thickening, and transversal grooves or ridges, none of which were seen in our patient.²

Children with nail-patella syndrome have dysplastic nails and associated bony abnormalities, such as absent patellae.⁵ This syndrome results from an autosomaldominant mutation in the LIM homeobox transcription factor 1-beta gene, LMX1B, which is responsible for dorsal-ventral patterning of the limb, as well as patterning of the nails, patellae and long bones, and even the kidney tubule.⁶ As such, patients with nail-patella syndrome have associated renal abnormalities. The findings in our patient were limited to the feet, making an underlying syndrome unlikely to be the cause.

First described in 1968 by Meadow,⁷ fetal hydantoin syndrome is a well-documented sequela in women taking phenytoin throughout pregnancy. Multiple malformations are possible, including cardiac defects, cleft lip/palate, digit and nail hypoplasia, abnormal facial features, mental disability, and growth abnormalities.⁸ The teratogenicity behind phenytoin results from reactive oxygen species that alter embryonic DNA, proteins, and lipids.⁹ The mother of this child was not on any seizure prophylaxis, eliminating it from the differential.

Congenital hypertrophy of the lateral nail fold is a defect of the soft tissue of the hallux leading to hypertrophy of the nail fold, commonly presenting with inflammation and pain¹⁰ possibly due to dyssynchronous growth between the soft tissue and nail plate.¹¹ With this defect, a lip covering the nail plate is common, which was not seen in our patient.

As demonstrated in our patient, family history can help guide the diagnosis. Seven of 9 nonsyndromic forms of syndactyly are inherited in an autosomal-dominant fashion and range from mild presentations, as in our patient, to more severe deformations with underlying bone fusion and functional impairment.¹² Polydactyly also often is expressed in an autosomal-dominant pattern, with up to 30% of patients having a positive family history. Polydactyly traditionally is classified by the location of the supernumerary digit as preaxial (radial), central, or postaxial (ulnar), and many further morphologic variations exist within these groups. Overall, preaxial polydactyly is relatively rare and represents 15% of polydactylies, with central and postaxial comprising the other 6% and 79%, respectively.¹³ Delineation of the underlying anatomy may reveal ray duplications (digit and corresponding metacarpal or metatarsal bone), metatarsal variants, and duplicated phalanges that may be hypoplastic or deformed. Patients may report difficulty finding comfortable footwear, cosmetic concerns, and nail-related complications. Although not always required, surgical intervention may provide definitive treatment but can leave residual deformities in the surrounding altered anatomy; thus, orthopedic or plastic surgery consultations are critical in appropriately counseling patients.

The Diagnosis: Onychodystrophy Secondary to Polydactyly

Radiographs of the feet demonstrated an accessory distal phalanx of the left great toe with a similar smaller accessory distal phalanx on the right great toe (Figure). The patient was referred to orthopedic surgery, and surgical intervention was recommended for only the left great toe given recurrent skin inflammation and nail complications. An excision of the left great toe polydactyly was performed. The patient healed well without complications.

Many clinically heterogeneous phenotypes exist for polydactyly and syndactyly, which both are common entities with incidences of 1 in 700 to 1000 births and 1 in 2000 to 3000 births, respectively.¹ Both polydactyly and syndactyly can be an isolated variant in newborns or present with multiple concurrent malformations as part of a genetic syndrome, with more than 300 syndromic anomalies described. The genetic basis of these conditions is equally diverse, with homeobox genes, hedgehog pathways, fibroblast growth factors, and boneand cartilage-derived morphogenetic proteins implicated in their development.¹

The differential diagnosis for our patient included congenital malalignment of the great toenails, nail-patella syndrome, onychodystrophy secondary to polydactyly, and congenital hypertrophy of the lateral nail fold. Given the strong family history, polydactyly was suspected.

Congenital malalignment of the great toenails results in lateral deviation of the nail plates.² It is an underdiagnosed condition with different etiologies hypothesized, such as genetic factors with possible autosomal-dominant transmission and extrinsic factors.³ One proposed mechanism of pathogenesis is desynchronization during growth of the nail and distal phalanx of the hallux, leading to larger nail plates that grow laterally.⁴ Typical features associated with this disease are nail discoloration, nail plate thickening, and transversal grooves or ridges, none of which were seen in our patient.²

Children with nail-patella syndrome have dysplastic nails and associated bony abnormalities, such as absent patellae.⁵ This syndrome results from an autosomaldominant mutation in the LIM homeobox transcription factor 1-beta gene, LMX1B, which is responsible for dorsal-ventral patterning of the limb, as well as patterning of the nails, patellae and long bones, and even the kidney tubule.⁶ As such, patients with nail-patella syndrome have associated renal abnormalities. The findings in our patient were limited to the feet, making an underlying syndrome unlikely to be the cause.

First described in 1968 by Meadow,⁷ fetal hydantoin syndrome is a well-documented sequela in women taking phenytoin throughout pregnancy. Multiple malformations are possible, including cardiac defects, cleft lip/palate, digit and nail hypoplasia, abnormal facial features, mental disability, and growth abnormalities.⁸ The teratogenicity behind phenytoin results from reactive oxygen species that alter embryonic DNA, proteins, and lipids.⁹ The mother of this child was not on any seizure prophylaxis, eliminating it from the differential.

Congenital hypertrophy of the lateral nail fold is a defect of the soft tissue of the hallux leading to hypertrophy of the nail fold, commonly presenting with inflammation and pain¹⁰ possibly due to dyssynchronous growth between the soft tissue and nail plate.¹¹ With this defect, a lip covering the nail plate is common, which was not seen in our patient.

As demonstrated in our patient, family history can help guide the diagnosis. Seven of 9 nonsyndromic forms of syndactyly are inherited in an autosomal-dominant fashion and range from mild presentations, as in our patient, to more severe deformations with underlying bone fusion and functional impairment.¹² Polydactyly also often is expressed in an autosomal-dominant pattern, with up to 30% of patients having a positive family history. Polydactyly traditionally is classified by the location of the supernumerary digit as preaxial (radial), central, or postaxial (ulnar), and many further morphologic variations exist within these groups. Overall, preaxial polydactyly is relatively rare and represents 15% of polydactylies, with central and postaxial comprising the other 6% and 79%, respectively.¹³ Delineation of the underlying anatomy may reveal ray duplications (digit and corresponding metacarpal or metatarsal bone), metatarsal variants, and duplicated phalanges that may be hypoplastic or deformed. Patients may report difficulty finding comfortable footwear, cosmetic concerns, and nail-related complications. Although not always required, surgical intervention may provide definitive treatment but can leave residual deformities in the surrounding altered anatomy; thus, orthopedic or plastic surgery consultations are critical in appropriately counseling patients.

The Diagnosis: Granular Parakeratosis 

Microscopic examination of a punch biopsy from the left axilla revealed verruciform epidermal hyperplasia with overlying parakeratosis and retention of keratohyalin granules in the stratum corneum (Figure). There was no evidence of acantholysis, dyskeratosis, epidermal neutrophils, or neutrophilic microabscesses. 

The patient's history and characteristic histopathologic findings confirmed the diagnosis of granular parakeratosis (GP). He was instructed to discontinue his current antiperspirant and began treatment with topical fluocinolone oil 0.01% every morning and urea cream 20% every night. Complete resolution was achieved within 2 weeks, and he reported no recurrence at a 2-year follow-up visit.  

Granular parakeratosis is a rare idiopathic skin condition characterized by hyperkeratotic papules and plaques, most often in intertriginous areas. Described by Northcutt et al¹ as a contact reaction to antiperspirant in the axillae, GP also has been reported in the submammary and inguinal creases² and rarely in nonintertriginous sites such as the abdomen.³ Although deodorants and antiperspirants in roll-on or stick form classically are implicated in GP, the condition also has been observed with exposure to laundry detergents containing benzalkonium chloride.⁴ Lesions with GP histology also have been incidentally observed in association with dermatophytosis,⁵ dermatomyositis,⁶ molluscum contagiosum,⁷ and carcinomas.⁸ Ding et al⁹ proposed that GP be reclassified as a reaction pattern observed in the skin as opposed to being a distinct disease entity.  

Clinically, GP presents as pruritic intertriginous papules and coalescent plaques that most commonly are seen in the axillae but also may involve the groin or other sites.^2,3 Both pruritus and disease burden can be aggravated by heat, sweating, or friction. There may be a history of a new irritant exposure prior to symptom onset, but GP has been observed in the absence of identifiable exposures and in the setting of long-term antiperspirant or deodorant use.³ Although a family history may be helpful, it can be difficult to distinguish GP from entities such as Hailey-Hailey disease or Darier disease based on history and examination alone; a biopsy often is necessary for definitive diagnosis. 

Histologically, GP demonstrates acanthosis with parakeratosis and retention of keratohyalin granules in the stratum corneum.¹ The stratum granulosum is preserved. On cursory examination, GP may resemble a psoriasiform dermatosis as can be seen in inverse psoriasis; however, neutrophilic microabscesses and infiltrates are not seen. Absence of acantholysis and dyskeratosis further differentiates GP from the clinically similar Hailey-Hailey disease and Darier disease. Spongiosis that is prominently found in allergic contact dermatitis also is absent. 

Although a benign disorder, GP warrants treatment to achieve symptomatic relief. A mainstay of treatment is to eliminate exposure to suspected aggravating or inciting factors such as antiperspirants or deodorants. A variety of treatments including laser therapy, corticosteroids, isotretinoin, and vitamin D analogs such as calcipotriene and calcitriol have been reported to be effective treatments of GP in case studies and series.^3,10 Large-scale clinical trials are not available because of the rarity of this condition. Our patient's clinical course suggests topical fluocinolone and urea in combination can be considered to achieve rapid resolution. 

The Diagnosis: Granular Parakeratosis 

Microscopic examination of a punch biopsy from the left axilla revealed verruciform epidermal hyperplasia with overlying parakeratosis and retention of keratohyalin granules in the stratum corneum (Figure). There was no evidence of acantholysis, dyskeratosis, epidermal neutrophils, or neutrophilic microabscesses. 

The patient's history and characteristic histopathologic findings confirmed the diagnosis of granular parakeratosis (GP). He was instructed to discontinue his current antiperspirant and began treatment with topical fluocinolone oil 0.01% every morning and urea cream 20% every night. Complete resolution was achieved within 2 weeks, and he reported no recurrence at a 2-year follow-up visit.  

Granular parakeratosis is a rare idiopathic skin condition characterized by hyperkeratotic papules and plaques, most often in intertriginous areas. Described by Northcutt et al¹ as a contact reaction to antiperspirant in the axillae, GP also has been reported in the submammary and inguinal creases² and rarely in nonintertriginous sites such as the abdomen.³ Although deodorants and antiperspirants in roll-on or stick form classically are implicated in GP, the condition also has been observed with exposure to laundry detergents containing benzalkonium chloride.⁴ Lesions with GP histology also have been incidentally observed in association with dermatophytosis,⁵ dermatomyositis,⁶ molluscum contagiosum,⁷ and carcinomas.⁸ Ding et al⁹ proposed that GP be reclassified as a reaction pattern observed in the skin as opposed to being a distinct disease entity.  

Clinically, GP presents as pruritic intertriginous papules and coalescent plaques that most commonly are seen in the axillae but also may involve the groin or other sites.^2,3 Both pruritus and disease burden can be aggravated by heat, sweating, or friction. There may be a history of a new irritant exposure prior to symptom onset, but GP has been observed in the absence of identifiable exposures and in the setting of long-term antiperspirant or deodorant use.³ Although a family history may be helpful, it can be difficult to distinguish GP from entities such as Hailey-Hailey disease or Darier disease based on history and examination alone; a biopsy often is necessary for definitive diagnosis. 

Histologically, GP demonstrates acanthosis with parakeratosis and retention of keratohyalin granules in the stratum corneum.¹ The stratum granulosum is preserved. On cursory examination, GP may resemble a psoriasiform dermatosis as can be seen in inverse psoriasis; however, neutrophilic microabscesses and infiltrates are not seen. Absence of acantholysis and dyskeratosis further differentiates GP from the clinically similar Hailey-Hailey disease and Darier disease. Spongiosis that is prominently found in allergic contact dermatitis also is absent. 

Although a benign disorder, GP warrants treatment to achieve symptomatic relief. A mainstay of treatment is to eliminate exposure to suspected aggravating or inciting factors such as antiperspirants or deodorants. A variety of treatments including laser therapy, corticosteroids, isotretinoin, and vitamin D analogs such as calcipotriene and calcitriol have been reported to be effective treatments of GP in case studies and series.^3,10 Large-scale clinical trials are not available because of the rarity of this condition. Our patient's clinical course suggests topical fluocinolone and urea in combination can be considered to achieve rapid resolution. 

The Diagnosis: Granular Parakeratosis 

Microscopic examination of a punch biopsy from the left axilla revealed verruciform epidermal hyperplasia with overlying parakeratosis and retention of keratohyalin granules in the stratum corneum (Figure). There was no evidence of acantholysis, dyskeratosis, epidermal neutrophils, or neutrophilic microabscesses. 

The patient's history and characteristic histopathologic findings confirmed the diagnosis of granular parakeratosis (GP). He was instructed to discontinue his current antiperspirant and began treatment with topical fluocinolone oil 0.01% every morning and urea cream 20% every night. Complete resolution was achieved within 2 weeks, and he reported no recurrence at a 2-year follow-up visit.  

Granular parakeratosis is a rare idiopathic skin condition characterized by hyperkeratotic papules and plaques, most often in intertriginous areas. Described by Northcutt et al¹ as a contact reaction to antiperspirant in the axillae, GP also has been reported in the submammary and inguinal creases² and rarely in nonintertriginous sites such as the abdomen.³ Although deodorants and antiperspirants in roll-on or stick form classically are implicated in GP, the condition also has been observed with exposure to laundry detergents containing benzalkonium chloride.⁴ Lesions with GP histology also have been incidentally observed in association with dermatophytosis,⁵ dermatomyositis,⁶ molluscum contagiosum,⁷ and carcinomas.⁸ Ding et al⁹ proposed that GP be reclassified as a reaction pattern observed in the skin as opposed to being a distinct disease entity.  

Clinically, GP presents as pruritic intertriginous papules and coalescent plaques that most commonly are seen in the axillae but also may involve the groin or other sites.^2,3 Both pruritus and disease burden can be aggravated by heat, sweating, or friction. There may be a history of a new irritant exposure prior to symptom onset, but GP has been observed in the absence of identifiable exposures and in the setting of long-term antiperspirant or deodorant use.³ Although a family history may be helpful, it can be difficult to distinguish GP from entities such as Hailey-Hailey disease or Darier disease based on history and examination alone; a biopsy often is necessary for definitive diagnosis. 

Histologically, GP demonstrates acanthosis with parakeratosis and retention of keratohyalin granules in the stratum corneum.¹ The stratum granulosum is preserved. On cursory examination, GP may resemble a psoriasiform dermatosis as can be seen in inverse psoriasis; however, neutrophilic microabscesses and infiltrates are not seen. Absence of acantholysis and dyskeratosis further differentiates GP from the clinically similar Hailey-Hailey disease and Darier disease. Spongiosis that is prominently found in allergic contact dermatitis also is absent. 

Although a benign disorder, GP warrants treatment to achieve symptomatic relief. A mainstay of treatment is to eliminate exposure to suspected aggravating or inciting factors such as antiperspirants or deodorants. A variety of treatments including laser therapy, corticosteroids, isotretinoin, and vitamin D analogs such as calcipotriene and calcitriol have been reported to be effective treatments of GP in case studies and series.^3,10 Large-scale clinical trials are not available because of the rarity of this condition. Our patient's clinical course suggests topical fluocinolone and urea in combination can be considered to achieve rapid resolution. 

The Diagnosis: Lichen Planus Pemphigoides

A skin biopsy from the right thigh demonstrated subepidermal blisters containing neutrophils (Figure 1). Direct immunofluorescence revealed linear basement membrane zone staining with C3 and trace staining with IgG (Figure 2), supporting a diagnosis of lichen planus pemphigoides (LPP). Oral prednisone—starting at 60 mg daily and tapered to 40 mg for a week, 20 mg for a week, then 10 mg for a month—along with triamcinolone ointment 0.1% to affected areas led to improvement. Hydrochlorothiazide and UV light therapy were discontinued. Doxycycline 100 mg twice daily and nicotinamide 500 mg twice daily prescribed as adjunctive therapy also led to improvement. The patient achieved remission with doxycycline and was doing well without prednisone; however, he experienced a flare of his disease about 6 months later and was started on mycophenolate mofetil 1 g twice daily after clearance from his gastroenterologist, given his history of hepatitis B. He has been doing well since starting mycophenolate mofetil.

Lichen planus pemphigoides is a rare autoimmune bullous dermatosis with features of both lichen planus and bullous pemphigoid.¹ Violaceous papules and tense bullae may be superimposed or arise independently. The chest, abdomen, back, and upper and lower extremities typically are involved.² Oral mucosal involvement with white reticular streaks or erosions and nail involvement have been reported.² Histopathologic and immunologic findings establish the diagnosis. Lichen planus pemphigoides is associated with subepidermal bullae and linear deposits of IgG and C3 on the basement membrane zone.¹ Autoantibodies to bullous pemphigoid (BP) antigens BP180 and BP230 are associated with LPP.³ The pathogenesis of LPP remains unclear, but there are associations with chronic diseases, medications, and certain therapies.^1,4-6 Several case reports have linked LPP to chronic viral hepatitis infections, as well as malignant tumors of the skin, mucosa, and gastrointestinal tract.² Lichen planus pemphigoides has been reported in a patient on entecavir for hepatitis B as well as in a patient treated for hepatitis C with interferon and ribavirin.¹ Lichen planus pemphigoides has been described in patients treated with the angiotensin-converting enzyme inhibitors enalapril, captopril, and ramipril.^4,5,7 UV phototherapy also has been associated with the development of LPP.⁶ Hydrochlorothiazide previously has been reported as a cause of drug-induced lichen planus.⁸ A PubMed search of articles indexed for MEDLINE using the terms lichen planus pemphigoides and hydrochlorothiazide revealed no reports of hydrochlorothiazide-induced LPP.

Lichen planus pemphigoides demonstrates overlap with other blistering dermatoses, such as BP, bullous lupus erythematosus, and bullous lichen planus. Although histologically and immunologically similar to BP, LPP can be differentiated clinically by the presence of violaceous papules or plaques typical of lichen planus.⁹ Bullous pemphigoid is more common in individuals older than 70 years, whereas LPP tends to occur in middle-aged adults.² Bullous lupus erythematosus usually is associated with manifestations of systemic lupus erythematosus and autoantibodies to collagen type VII.¹⁰ Salt-split skin studies demonstrate immunofluorescence on the dermal side of the split. Individuals affected by bullous lupus erythematosus typically have a history of photosensitivity.¹⁰ Blisters in LPP may form de novo from unaffected skin, whereas the bullae in bullous lichen planus are limited to existing lichenoid papules.⁹ The autoantibodies typical of LPP are absent in bullous lichen planus. Lichen planus actinicus is a variant of lichen planus that presents with annular, dyschromic, or violaceous plaques in a photodistributed pattern without bullous lesions.⁹

Lichen planus pemphigoides most commonly is treated with systemic corticosteroids. Topical steroids, dapsone, erythromycin, tetracycline and nicotinamide, azathioprine, and mycophenolate mofetil have been reported as adjuncts to systemic steroid therapy.^2,11 Most reports describe treatment success with resolution of blistering lesions.

The Diagnosis: Lichen Planus Pemphigoides

A skin biopsy from the right thigh demonstrated subepidermal blisters containing neutrophils (Figure 1). Direct immunofluorescence revealed linear basement membrane zone staining with C3 and trace staining with IgG (Figure 2), supporting a diagnosis of lichen planus pemphigoides (LPP). Oral prednisone—starting at 60 mg daily and tapered to 40 mg for a week, 20 mg for a week, then 10 mg for a month—along with triamcinolone ointment 0.1% to affected areas led to improvement. Hydrochlorothiazide and UV light therapy were discontinued. Doxycycline 100 mg twice daily and nicotinamide 500 mg twice daily prescribed as adjunctive therapy also led to improvement. The patient achieved remission with doxycycline and was doing well without prednisone; however, he experienced a flare of his disease about 6 months later and was started on mycophenolate mofetil 1 g twice daily after clearance from his gastroenterologist, given his history of hepatitis B. He has been doing well since starting mycophenolate mofetil.

Lichen planus pemphigoides is a rare autoimmune bullous dermatosis with features of both lichen planus and bullous pemphigoid.¹ Violaceous papules and tense bullae may be superimposed or arise independently. The chest, abdomen, back, and upper and lower extremities typically are involved.² Oral mucosal involvement with white reticular streaks or erosions and nail involvement have been reported.² Histopathologic and immunologic findings establish the diagnosis. Lichen planus pemphigoides is associated with subepidermal bullae and linear deposits of IgG and C3 on the basement membrane zone.¹ Autoantibodies to bullous pemphigoid (BP) antigens BP180 and BP230 are associated with LPP.³ The pathogenesis of LPP remains unclear, but there are associations with chronic diseases, medications, and certain therapies.^1,4-6 Several case reports have linked LPP to chronic viral hepatitis infections, as well as malignant tumors of the skin, mucosa, and gastrointestinal tract.² Lichen planus pemphigoides has been reported in a patient on entecavir for hepatitis B as well as in a patient treated for hepatitis C with interferon and ribavirin.¹ Lichen planus pemphigoides has been described in patients treated with the angiotensin-converting enzyme inhibitors enalapril, captopril, and ramipril.^4,5,7 UV phototherapy also has been associated with the development of LPP.⁶ Hydrochlorothiazide previously has been reported as a cause of drug-induced lichen planus.⁸ A PubMed search of articles indexed for MEDLINE using the terms lichen planus pemphigoides and hydrochlorothiazide revealed no reports of hydrochlorothiazide-induced LPP.

Lichen planus pemphigoides demonstrates overlap with other blistering dermatoses, such as BP, bullous lupus erythematosus, and bullous lichen planus. Although histologically and immunologically similar to BP, LPP can be differentiated clinically by the presence of violaceous papules or plaques typical of lichen planus.⁹ Bullous pemphigoid is more common in individuals older than 70 years, whereas LPP tends to occur in middle-aged adults.² Bullous lupus erythematosus usually is associated with manifestations of systemic lupus erythematosus and autoantibodies to collagen type VII.¹⁰ Salt-split skin studies demonstrate immunofluorescence on the dermal side of the split. Individuals affected by bullous lupus erythematosus typically have a history of photosensitivity.¹⁰ Blisters in LPP may form de novo from unaffected skin, whereas the bullae in bullous lichen planus are limited to existing lichenoid papules.⁹ The autoantibodies typical of LPP are absent in bullous lichen planus. Lichen planus actinicus is a variant of lichen planus that presents with annular, dyschromic, or violaceous plaques in a photodistributed pattern without bullous lesions.⁹

Lichen planus pemphigoides most commonly is treated with systemic corticosteroids. Topical steroids, dapsone, erythromycin, tetracycline and nicotinamide, azathioprine, and mycophenolate mofetil have been reported as adjuncts to systemic steroid therapy.^2,11 Most reports describe treatment success with resolution of blistering lesions.

The Diagnosis: Lichen Planus Pemphigoides

A skin biopsy from the right thigh demonstrated subepidermal blisters containing neutrophils (Figure 1). Direct immunofluorescence revealed linear basement membrane zone staining with C3 and trace staining with IgG (Figure 2), supporting a diagnosis of lichen planus pemphigoides (LPP). Oral prednisone—starting at 60 mg daily and tapered to 40 mg for a week, 20 mg for a week, then 10 mg for a month—along with triamcinolone ointment 0.1% to affected areas led to improvement. Hydrochlorothiazide and UV light therapy were discontinued. Doxycycline 100 mg twice daily and nicotinamide 500 mg twice daily prescribed as adjunctive therapy also led to improvement. The patient achieved remission with doxycycline and was doing well without prednisone; however, he experienced a flare of his disease about 6 months later and was started on mycophenolate mofetil 1 g twice daily after clearance from his gastroenterologist, given his history of hepatitis B. He has been doing well since starting mycophenolate mofetil.

Lichen planus pemphigoides is a rare autoimmune bullous dermatosis with features of both lichen planus and bullous pemphigoid.¹ Violaceous papules and tense bullae may be superimposed or arise independently. The chest, abdomen, back, and upper and lower extremities typically are involved.² Oral mucosal involvement with white reticular streaks or erosions and nail involvement have been reported.² Histopathologic and immunologic findings establish the diagnosis. Lichen planus pemphigoides is associated with subepidermal bullae and linear deposits of IgG and C3 on the basement membrane zone.¹ Autoantibodies to bullous pemphigoid (BP) antigens BP180 and BP230 are associated with LPP.³ The pathogenesis of LPP remains unclear, but there are associations with chronic diseases, medications, and certain therapies.^1,4-6 Several case reports have linked LPP to chronic viral hepatitis infections, as well as malignant tumors of the skin, mucosa, and gastrointestinal tract.² Lichen planus pemphigoides has been reported in a patient on entecavir for hepatitis B as well as in a patient treated for hepatitis C with interferon and ribavirin.¹ Lichen planus pemphigoides has been described in patients treated with the angiotensin-converting enzyme inhibitors enalapril, captopril, and ramipril.^4,5,7 UV phototherapy also has been associated with the development of LPP.⁶ Hydrochlorothiazide previously has been reported as a cause of drug-induced lichen planus.⁸ A PubMed search of articles indexed for MEDLINE using the terms lichen planus pemphigoides and hydrochlorothiazide revealed no reports of hydrochlorothiazide-induced LPP.

Lichen planus pemphigoides demonstrates overlap with other blistering dermatoses, such as BP, bullous lupus erythematosus, and bullous lichen planus. Although histologically and immunologically similar to BP, LPP can be differentiated clinically by the presence of violaceous papules or plaques typical of lichen planus.⁹ Bullous pemphigoid is more common in individuals older than 70 years, whereas LPP tends to occur in middle-aged adults.² Bullous lupus erythematosus usually is associated with manifestations of systemic lupus erythematosus and autoantibodies to collagen type VII.¹⁰ Salt-split skin studies demonstrate immunofluorescence on the dermal side of the split. Individuals affected by bullous lupus erythematosus typically have a history of photosensitivity.¹⁰ Blisters in LPP may form de novo from unaffected skin, whereas the bullae in bullous lichen planus are limited to existing lichenoid papules.⁹ The autoantibodies typical of LPP are absent in bullous lichen planus. Lichen planus actinicus is a variant of lichen planus that presents with annular, dyschromic, or violaceous plaques in a photodistributed pattern without bullous lesions.⁹

Lichen planus pemphigoides most commonly is treated with systemic corticosteroids. Topical steroids, dapsone, erythromycin, tetracycline and nicotinamide, azathioprine, and mycophenolate mofetil have been reported as adjuncts to systemic steroid therapy.^2,11 Most reports describe treatment success with resolution of blistering lesions.

The Diagnosis: Addison Disease in the Context of Polyglandular Autoimmune Syndrome Type 2

The patient’s hormone levels as well as distinct clinical features led to a diagnosis of Addison disease in the context of polyglandular autoimmune syndrome type 2 (PAS-2). Approximately 50% of PAS-2 cases are familiar, and different modes of inheritance—autosomal recessive, autosomal dominant, and polygenic—have been reported. Women are affected up to 3 times more often than men.^1,2 The age of onset ranges from infancy to late adulthood, with most cases occurring in early adulthood. Primary adrenal insufficiency (Addison disease) is  the principal manifestation of PAS-2. It appears in approximately 50% of patients, occurring simultaneously with autoimmune thyroid disease or diabetes mellitus in 20% of patients and following them in 30% of patients.^1,2 Autoimmune thyroid diseases such as chronic autoimmune thyroiditis and occasionally Graves disease as well as type 1 diabetes mellitus also are common. Polyglandular autoimmune syndrome type 2 with primary adrenal insufficiency and autoimmune thyroid disease was formerly referred to as Schmidt syndrome.³ It must be differentiated from polyglandular autoimmune syndrome type 1, a rare condition that also is referred to as autoimmune polyendocrinopathycandidiasis-ectodermal dystrophy syndrome.^1,3 As with any other cause of adrenal insufficiency, the treatment involves hormone replacement therapy up to normal levels and then tapering according to stress levels (ie, surgery or infections that require a dose increase). Our patient was diagnosed according to hormone levels and clinical features and was started on 30 mg daily of hydrocortisone and 50 μg daily of levothyroxine. No improvement in her condition was noted after 6 months of treatment. The patient is still under yearly follow-up, and the mucous hyperpigmentation faded approximately 6 months after hormonal homeostasis was achieved.

Peutz-Jeghers syndrome is inherited in an autosomal-dominant fashion. It is characterized by multiple hamartomatous polyps in the gastrointestinal tract, mucocutaneous pigmentation, and an increased risk for gastrointestinal and nongastrointestinal cancer. Mucocutaneous pigmented macules most commonly occur on the lips and perioral region, buccal mucosa, and the palms and soles. However, mucocutaneous pigmentation usually occurs during the first 1 to 2 years of life, increases in size and number over the ensuing years, and usually fades after puberty.⁴

Laugier-Hunziker syndrome is an acquired benign disorder presenting in adults with lentigines on the lips and buccal mucosa. It frequently is accompaniedby longitudinal melanonychia, macular pigmentation of the genitals, and involvement of the palms and soles. The diagnosis of Laugier-Hunziker syndrome is one of exclusion and is made after ruling out other causes of oral and labial hyperpigmentation, including physiologic pigmentation seen in darker-skinned individuals as well as inherited diseases associated with lentiginosis, requiring complete physical examination, endoscopy, and colonscopy.⁵

A wide variety of drugs and chemicals can lead to diffuse cutaneous hyperpigmentation. Increased production of melanin and/or the deposition of drug complexes or metals in the dermis is responsible for the skin discoloration. Drugs that most often cause hyperpigmentation on mucosal surfaces are hydroxychloroquine, minocycline, nicotine, silver, and some chemotherapy agents. The hyperpigmentation usually resolves with discontinuation of the offending agent, but the course may be prolonged over months to years.⁶

Changes in the skin and subcutaneous tissue occur in patients with Cushing syndrome. Hyperpigmentation is induced by increased secretion of adrenocorticotropic hormone, not cortisol, and occurs most often in patients with the ectopic adrenocorticotropic hormone syndrome. Hyperpigmentation may be generalized but is more intense in areas exposed to light (eg, face, neck, dorsal aspects of the hands) or to chronic mild trauma, friction, or pressure (eg, elbows, knees, spine, knuckles). Patchy pigmentation may occur on the inner surface of the lips and the buccal mucosa along the line of dental occlusion. Acanthosis nigricans also can be present in the axillae and around the neck.⁷

The Diagnosis: Addison Disease in the Context of Polyglandular Autoimmune Syndrome Type 2

The patient’s hormone levels as well as distinct clinical features led to a diagnosis of Addison disease in the context of polyglandular autoimmune syndrome type 2 (PAS-2). Approximately 50% of PAS-2 cases are familiar, and different modes of inheritance—autosomal recessive, autosomal dominant, and polygenic—have been reported. Women are affected up to 3 times more often than men.^1,2 The age of onset ranges from infancy to late adulthood, with most cases occurring in early adulthood. Primary adrenal insufficiency (Addison disease) is  the principal manifestation of PAS-2. It appears in approximately 50% of patients, occurring simultaneously with autoimmune thyroid disease or diabetes mellitus in 20% of patients and following them in 30% of patients.^1,2 Autoimmune thyroid diseases such as chronic autoimmune thyroiditis and occasionally Graves disease as well as type 1 diabetes mellitus also are common. Polyglandular autoimmune syndrome type 2 with primary adrenal insufficiency and autoimmune thyroid disease was formerly referred to as Schmidt syndrome.³ It must be differentiated from polyglandular autoimmune syndrome type 1, a rare condition that also is referred to as autoimmune polyendocrinopathycandidiasis-ectodermal dystrophy syndrome.^1,3 As with any other cause of adrenal insufficiency, the treatment involves hormone replacement therapy up to normal levels and then tapering according to stress levels (ie, surgery or infections that require a dose increase). Our patient was diagnosed according to hormone levels and clinical features and was started on 30 mg daily of hydrocortisone and 50 μg daily of levothyroxine. No improvement in her condition was noted after 6 months of treatment. The patient is still under yearly follow-up, and the mucous hyperpigmentation faded approximately 6 months after hormonal homeostasis was achieved.

Peutz-Jeghers syndrome is inherited in an autosomal-dominant fashion. It is characterized by multiple hamartomatous polyps in the gastrointestinal tract, mucocutaneous pigmentation, and an increased risk for gastrointestinal and nongastrointestinal cancer. Mucocutaneous pigmented macules most commonly occur on the lips and perioral region, buccal mucosa, and the palms and soles. However, mucocutaneous pigmentation usually occurs during the first 1 to 2 years of life, increases in size and number over the ensuing years, and usually fades after puberty.⁴

Laugier-Hunziker syndrome is an acquired benign disorder presenting in adults with lentigines on the lips and buccal mucosa. It frequently is accompaniedby longitudinal melanonychia, macular pigmentation of the genitals, and involvement of the palms and soles. The diagnosis of Laugier-Hunziker syndrome is one of exclusion and is made after ruling out other causes of oral and labial hyperpigmentation, including physiologic pigmentation seen in darker-skinned individuals as well as inherited diseases associated with lentiginosis, requiring complete physical examination, endoscopy, and colonscopy.⁵

A wide variety of drugs and chemicals can lead to diffuse cutaneous hyperpigmentation. Increased production of melanin and/or the deposition of drug complexes or metals in the dermis is responsible for the skin discoloration. Drugs that most often cause hyperpigmentation on mucosal surfaces are hydroxychloroquine, minocycline, nicotine, silver, and some chemotherapy agents. The hyperpigmentation usually resolves with discontinuation of the offending agent, but the course may be prolonged over months to years.⁶

Changes in the skin and subcutaneous tissue occur in patients with Cushing syndrome. Hyperpigmentation is induced by increased secretion of adrenocorticotropic hormone, not cortisol, and occurs most often in patients with the ectopic adrenocorticotropic hormone syndrome. Hyperpigmentation may be generalized but is more intense in areas exposed to light (eg, face, neck, dorsal aspects of the hands) or to chronic mild trauma, friction, or pressure (eg, elbows, knees, spine, knuckles). Patchy pigmentation may occur on the inner surface of the lips and the buccal mucosa along the line of dental occlusion. Acanthosis nigricans also can be present in the axillae and around the neck.⁷

The Diagnosis: Addison Disease in the Context of Polyglandular Autoimmune Syndrome Type 2

The patient’s hormone levels as well as distinct clinical features led to a diagnosis of Addison disease in the context of polyglandular autoimmune syndrome type 2 (PAS-2). Approximately 50% of PAS-2 cases are familiar, and different modes of inheritance—autosomal recessive, autosomal dominant, and polygenic—have been reported. Women are affected up to 3 times more often than men.^1,2 The age of onset ranges from infancy to late adulthood, with most cases occurring in early adulthood. Primary adrenal insufficiency (Addison disease) is  the principal manifestation of PAS-2. It appears in approximately 50% of patients, occurring simultaneously with autoimmune thyroid disease or diabetes mellitus in 20% of patients and following them in 30% of patients.^1,2 Autoimmune thyroid diseases such as chronic autoimmune thyroiditis and occasionally Graves disease as well as type 1 diabetes mellitus also are common. Polyglandular autoimmune syndrome type 2 with primary adrenal insufficiency and autoimmune thyroid disease was formerly referred to as Schmidt syndrome.³ It must be differentiated from polyglandular autoimmune syndrome type 1, a rare condition that also is referred to as autoimmune polyendocrinopathycandidiasis-ectodermal dystrophy syndrome.^1,3 As with any other cause of adrenal insufficiency, the treatment involves hormone replacement therapy up to normal levels and then tapering according to stress levels (ie, surgery or infections that require a dose increase). Our patient was diagnosed according to hormone levels and clinical features and was started on 30 mg daily of hydrocortisone and 50 μg daily of levothyroxine. No improvement in her condition was noted after 6 months of treatment. The patient is still under yearly follow-up, and the mucous hyperpigmentation faded approximately 6 months after hormonal homeostasis was achieved.

Peutz-Jeghers syndrome is inherited in an autosomal-dominant fashion. It is characterized by multiple hamartomatous polyps in the gastrointestinal tract, mucocutaneous pigmentation, and an increased risk for gastrointestinal and nongastrointestinal cancer. Mucocutaneous pigmented macules most commonly occur on the lips and perioral region, buccal mucosa, and the palms and soles. However, mucocutaneous pigmentation usually occurs during the first 1 to 2 years of life, increases in size and number over the ensuing years, and usually fades after puberty.⁴

Laugier-Hunziker syndrome is an acquired benign disorder presenting in adults with lentigines on the lips and buccal mucosa. It frequently is accompaniedby longitudinal melanonychia, macular pigmentation of the genitals, and involvement of the palms and soles. The diagnosis of Laugier-Hunziker syndrome is one of exclusion and is made after ruling out other causes of oral and labial hyperpigmentation, including physiologic pigmentation seen in darker-skinned individuals as well as inherited diseases associated with lentiginosis, requiring complete physical examination, endoscopy, and colonscopy.⁵

A wide variety of drugs and chemicals can lead to diffuse cutaneous hyperpigmentation. Increased production of melanin and/or the deposition of drug complexes or metals in the dermis is responsible for the skin discoloration. Drugs that most often cause hyperpigmentation on mucosal surfaces are hydroxychloroquine, minocycline, nicotine, silver, and some chemotherapy agents. The hyperpigmentation usually resolves with discontinuation of the offending agent, but the course may be prolonged over months to years.⁶

Changes in the skin and subcutaneous tissue occur in patients with Cushing syndrome. Hyperpigmentation is induced by increased secretion of adrenocorticotropic hormone, not cortisol, and occurs most often in patients with the ectopic adrenocorticotropic hormone syndrome. Hyperpigmentation may be generalized but is more intense in areas exposed to light (eg, face, neck, dorsal aspects of the hands) or to chronic mild trauma, friction, or pressure (eg, elbows, knees, spine, knuckles). Patchy pigmentation may occur on the inner surface of the lips and the buccal mucosa along the line of dental occlusion. Acanthosis nigricans also can be present in the axillae and around the neck.⁷

The Diagnosis: Cutaneous Mycobacterium avium-intracellulare Complex Infection 

Histopathologic evaluation revealed superficial and deep perivascular and periadnexal inflammation. The epidermis exhibited some vacuolar interface change and effacement with relatively sparse dyskeratotic cells. A lymphohistiocytic inflammatory infiltrate surrounded the blood vessels, nerves, and adnexal structures and extended into the subcutaneous fat (Figure). Acid-fast, Grocott-Gomori methenamine-silver, Gram, Fite, Treponema pallidum, and Alcian blue stains were performed at our institution and were all negative. Biopsies sent to the National Hansen's Disease (Leprosy) Program demonstrated scattered extracellular acid-fast organisms on Fite staining in the specimen of the forearm. Polymerase chain reaction testing for Mycobacterium leprae DNA was negative. DNA sequencing of the 16S ribosomal RNA gene matched Mycobacterium avium-intracellulare complex (MAC). In the workup of the hepatic mass, the patient incidentally was found to have large-cell transformation of chronic lymphocytic leukemia (CLL) and therefore was treated with bendamustine and rituximab as an outpatient. The patient received 1 chemotherapy infusion every 4 weeks for a total of 10 rounds. At 10-week follow-up after 2 rounds of chemotherapy, all of the skin lesions had resolved despite no antibiotic therapy for atypical infections.  

Disseminated infection with MAC is relatively rare in healthy as well as immunocompromised individuals. Clinical disease most commonly is seen as an opportunistic infection in patients with AIDS who have CD4 counts less than 50/mm³ (reference range, 500-1400/mm3) or in those with preexisting lung disease.¹ Cutaneous involvement has been observed in only 14% of non-AIDS patients with disseminated MAC infection.² In another study of 76 patients with MAC infection, only 2 involved the skin or soft tissue.³ Infection of the skin without concurrent pulmonary MAC infection is rare, though trauma may cause isolated skin infection. The cutaneous presentation of MAC infection is highly variable and may include erythematous papules, pustules, panniculitis, infiltrated plaques, verrucous lesions, and draining sinuses.³ The lesions have been reported to be painful.¹  

Cutaneous findings occur in up to 25% of patients with CLL, either due to the seeding of leukemic cells or other secondary lesions.⁴ Leukemia cutis, or skin involvement by B-cell CLL, most commonly presents in the head and neck region as chronic and relapsing erythematous papules and plaques.⁵ It histologically presents as monomorphic lymphocytic infiltrates accentuated around periadnexal and perivascular structures, with some extending into adipose tissue.² In our case, histopathology demonstrated a lack of monomorphous infiltrate and thus was inconsistent with leukemia cutis. Similarly, lack of pale pink deposits and lack of neutrophilic infiltrates or degenerated collagen makes amyloidosis and palisaded neutrophilic granulomatous dermatitis incorrect diagnoses, respectively. 

We hypothesize that the initially undetected worsening of CLL resulted in an immunocompromised state, which facilitated this unique presentation of cutaneous MAC infection in a human immunodeficiency virus-negative patient with no clinical symptoms of active pulmonary disease. The rash was the presenting sign of both the cutaneous MAC infection and worsening CLL. Additionally, our patient's cutaneous MAC facial involvement clinically resembled the leonine facies that is classic in lepromatous leprosy. Rare reports have been published addressing this similarity.⁶ 

Treatment of MAC pulmonary disease usually includes a combination of clarithromycin or azithromycin, rifampin, and ethambutol (for nodular/bronchiectatic disease), with or without amikacin or streptomycin.⁷ For limited pulmonary disease in patients with adequate pulmonary reserve, surgical resection may be considered in combination with the multidrug MAC pulmonary treatment regimen for 3 months to 1 year. Patients with localized MAC disease involving only the skin, soft tissue, tendons, and joints usually are treated with surgical excision in combination with clarithromycin, rifampin, and ethambutol for 6 to 12 months.⁷ In our patient, we believe that chemotherapy and the subsequent reconstituted immune system likely cleared the MAC infection without targeted antibiotic treatment.  
 

Acknowledgments
The authors would like to thank David Scollard, MD, PhD, and Barbara Stryjewska, MD, from the National Hansen's Disease (Leprosy) Association (Baton Rouge, Louisiana).  
 

The Diagnosis: Cutaneous Mycobacterium avium-intracellulare Complex Infection 

Histopathologic evaluation revealed superficial and deep perivascular and periadnexal inflammation. The epidermis exhibited some vacuolar interface change and effacement with relatively sparse dyskeratotic cells. A lymphohistiocytic inflammatory infiltrate surrounded the blood vessels, nerves, and adnexal structures and extended into the subcutaneous fat (Figure). Acid-fast, Grocott-Gomori methenamine-silver, Gram, Fite, Treponema pallidum, and Alcian blue stains were performed at our institution and were all negative. Biopsies sent to the National Hansen's Disease (Leprosy) Program demonstrated scattered extracellular acid-fast organisms on Fite staining in the specimen of the forearm. Polymerase chain reaction testing for Mycobacterium leprae DNA was negative. DNA sequencing of the 16S ribosomal RNA gene matched Mycobacterium avium-intracellulare complex (MAC). In the workup of the hepatic mass, the patient incidentally was found to have large-cell transformation of chronic lymphocytic leukemia (CLL) and therefore was treated with bendamustine and rituximab as an outpatient. The patient received 1 chemotherapy infusion every 4 weeks for a total of 10 rounds. At 10-week follow-up after 2 rounds of chemotherapy, all of the skin lesions had resolved despite no antibiotic therapy for atypical infections.  

Disseminated infection with MAC is relatively rare in healthy as well as immunocompromised individuals. Clinical disease most commonly is seen as an opportunistic infection in patients with AIDS who have CD4 counts less than 50/mm³ (reference range, 500-1400/mm3) or in those with preexisting lung disease.¹ Cutaneous involvement has been observed in only 14% of non-AIDS patients with disseminated MAC infection.² In another study of 76 patients with MAC infection, only 2 involved the skin or soft tissue.³ Infection of the skin without concurrent pulmonary MAC infection is rare, though trauma may cause isolated skin infection. The cutaneous presentation of MAC infection is highly variable and may include erythematous papules, pustules, panniculitis, infiltrated plaques, verrucous lesions, and draining sinuses.³ The lesions have been reported to be painful.¹  

Cutaneous findings occur in up to 25% of patients with CLL, either due to the seeding of leukemic cells or other secondary lesions.⁴ Leukemia cutis, or skin involvement by B-cell CLL, most commonly presents in the head and neck region as chronic and relapsing erythematous papules and plaques.⁵ It histologically presents as monomorphic lymphocytic infiltrates accentuated around periadnexal and perivascular structures, with some extending into adipose tissue.² In our case, histopathology demonstrated a lack of monomorphous infiltrate and thus was inconsistent with leukemia cutis. Similarly, lack of pale pink deposits and lack of neutrophilic infiltrates or degenerated collagen makes amyloidosis and palisaded neutrophilic granulomatous dermatitis incorrect diagnoses, respectively. 

We hypothesize that the initially undetected worsening of CLL resulted in an immunocompromised state, which facilitated this unique presentation of cutaneous MAC infection in a human immunodeficiency virus-negative patient with no clinical symptoms of active pulmonary disease. The rash was the presenting sign of both the cutaneous MAC infection and worsening CLL. Additionally, our patient's cutaneous MAC facial involvement clinically resembled the leonine facies that is classic in lepromatous leprosy. Rare reports have been published addressing this similarity.⁶ 

Treatment of MAC pulmonary disease usually includes a combination of clarithromycin or azithromycin, rifampin, and ethambutol (for nodular/bronchiectatic disease), with or without amikacin or streptomycin.⁷ For limited pulmonary disease in patients with adequate pulmonary reserve, surgical resection may be considered in combination with the multidrug MAC pulmonary treatment regimen for 3 months to 1 year. Patients with localized MAC disease involving only the skin, soft tissue, tendons, and joints usually are treated with surgical excision in combination with clarithromycin, rifampin, and ethambutol for 6 to 12 months.⁷ In our patient, we believe that chemotherapy and the subsequent reconstituted immune system likely cleared the MAC infection without targeted antibiotic treatment.  
 

Acknowledgments
The authors would like to thank David Scollard, MD, PhD, and Barbara Stryjewska, MD, from the National Hansen's Disease (Leprosy) Association (Baton Rouge, Louisiana).  
 

The Diagnosis: Cutaneous Mycobacterium avium-intracellulare Complex Infection 

Histopathologic evaluation revealed superficial and deep perivascular and periadnexal inflammation. The epidermis exhibited some vacuolar interface change and effacement with relatively sparse dyskeratotic cells. A lymphohistiocytic inflammatory infiltrate surrounded the blood vessels, nerves, and adnexal structures and extended into the subcutaneous fat (Figure). Acid-fast, Grocott-Gomori methenamine-silver, Gram, Fite, Treponema pallidum, and Alcian blue stains were performed at our institution and were all negative. Biopsies sent to the National Hansen's Disease (Leprosy) Program demonstrated scattered extracellular acid-fast organisms on Fite staining in the specimen of the forearm. Polymerase chain reaction testing for Mycobacterium leprae DNA was negative. DNA sequencing of the 16S ribosomal RNA gene matched Mycobacterium avium-intracellulare complex (MAC). In the workup of the hepatic mass, the patient incidentally was found to have large-cell transformation of chronic lymphocytic leukemia (CLL) and therefore was treated with bendamustine and rituximab as an outpatient. The patient received 1 chemotherapy infusion every 4 weeks for a total of 10 rounds. At 10-week follow-up after 2 rounds of chemotherapy, all of the skin lesions had resolved despite no antibiotic therapy for atypical infections.  

Disseminated infection with MAC is relatively rare in healthy as well as immunocompromised individuals. Clinical disease most commonly is seen as an opportunistic infection in patients with AIDS who have CD4 counts less than 50/mm³ (reference range, 500-1400/mm3) or in those with preexisting lung disease.¹ Cutaneous involvement has been observed in only 14% of non-AIDS patients with disseminated MAC infection.² In another study of 76 patients with MAC infection, only 2 involved the skin or soft tissue.³ Infection of the skin without concurrent pulmonary MAC infection is rare, though trauma may cause isolated skin infection. The cutaneous presentation of MAC infection is highly variable and may include erythematous papules, pustules, panniculitis, infiltrated plaques, verrucous lesions, and draining sinuses.³ The lesions have been reported to be painful.¹  

Cutaneous findings occur in up to 25% of patients with CLL, either due to the seeding of leukemic cells or other secondary lesions.⁴ Leukemia cutis, or skin involvement by B-cell CLL, most commonly presents in the head and neck region as chronic and relapsing erythematous papules and plaques.⁵ It histologically presents as monomorphic lymphocytic infiltrates accentuated around periadnexal and perivascular structures, with some extending into adipose tissue.² In our case, histopathology demonstrated a lack of monomorphous infiltrate and thus was inconsistent with leukemia cutis. Similarly, lack of pale pink deposits and lack of neutrophilic infiltrates or degenerated collagen makes amyloidosis and palisaded neutrophilic granulomatous dermatitis incorrect diagnoses, respectively. 

We hypothesize that the initially undetected worsening of CLL resulted in an immunocompromised state, which facilitated this unique presentation of cutaneous MAC infection in a human immunodeficiency virus-negative patient with no clinical symptoms of active pulmonary disease. The rash was the presenting sign of both the cutaneous MAC infection and worsening CLL. Additionally, our patient's cutaneous MAC facial involvement clinically resembled the leonine facies that is classic in lepromatous leprosy. Rare reports have been published addressing this similarity.⁶ 

Treatment of MAC pulmonary disease usually includes a combination of clarithromycin or azithromycin, rifampin, and ethambutol (for nodular/bronchiectatic disease), with or without amikacin or streptomycin.⁷ For limited pulmonary disease in patients with adequate pulmonary reserve, surgical resection may be considered in combination with the multidrug MAC pulmonary treatment regimen for 3 months to 1 year. Patients with localized MAC disease involving only the skin, soft tissue, tendons, and joints usually are treated with surgical excision in combination with clarithromycin, rifampin, and ethambutol for 6 to 12 months.⁷ In our patient, we believe that chemotherapy and the subsequent reconstituted immune system likely cleared the MAC infection without targeted antibiotic treatment.  
 

Acknowledgments
The authors would like to thank David Scollard, MD, PhD, and Barbara Stryjewska, MD, from the National Hansen's Disease (Leprosy) Association (Baton Rouge, Louisiana).