Dermatopathology

The Diagnosis: Cutaneous Metastasis

A shave biopsy of the lip revealed a diffuse cellular infiltrate filling the superficial and deep dermis (Figure 1A). Morphologically, the cells had abundant clear cytoplasm with eccentrically located, pleomorphic, hyperchromatic nuclei with occasional prominent nucleoli (Figure 1B). The cells stained positive for AE1/ AE3 on immunohistochemistry (Figure 2). A punch biopsy of the nodule in the right axillary vault revealed a morphologically similar proliferation of cells. A colonoscopy revealed a completely obstructing circumferential mass in the distal ascending colon. A biopsy of the mass confirmed invasive adenocarcinoma, supporting a diagnosis of cutaneous metastases from adenocarcinoma of the colon. The patient underwent resection of the lip tumor and started multiagent chemotherapy for his newly diagnosed stage IV adenocarcinoma of the colon. The patient died, despite therapy.

Cutaneous metastasis from solid malignancies is uncommon, as only 1.3% of them exhibit cutaneous manifestations at presentation.¹ Cutaneous metastasis from signet ring cell adenocarcinoma (SRCA) of the colon is uncommon, and cutaneous metastasis of colorectal SRCA rarely precedes the diagnosis of the primary lesion.² Among the colorectal cancers that metastasize to the skin, metastasis to the face occurs in only 0.5% of patients.³

Signet ring cell adenocarcinomas are poorly differentiated adenocarcinomas histologically characterized by the neoplastic cells’ circular to ovoid appearance with a flattened top.^4,5 This distinctive shape is from the displacement of the nucleus to the periphery of the cell due to the accumulation of intracytoplasmic mucin.⁴ Classically, malignancies are characterized as an SRCA if more than 50% of the cells have a signet ring cell morphology; if the signet ring cells comprise less than 50% of the neoplasm, the tumor is designated as an adenocarcinoma with signet ring morphology.⁴ The most common cause of cutaneous metastasis with signet ring morphology is gastric cancer, while colorectal carcinoma is less common.1 Colorectal SRCAs usually are found in the right colon or the rectum in comparison to other colonic sites.⁶

Clinically, cutaneous metastasis can present in a variety of ways. The most common presentation is nodular lesions that may coalesce to become zosteriform in configuration or lesions that mimic inflammatory dermatoses.⁷ Cutaneous metastasis is more common in breast and lung cancer, and when it occurs secondary to colorectal cancer, cutaneous metastasis rarely predates the detection of the primary neoplasm.²

The clinical appearance of metastasis is not specific and can mimic many entities⁸; therefore, a high index of suspicion must be employed when managing patients, even those without a history of internal malignancy. In our patient, the smooth nodular lesion appeared similar to a basal cell carcinoma; however, basal cell carcinomas appear more pearly, and arborizing telangiectasia often is seen.⁹ Merkel cell carcinoma is common on sundamaged skin of the head and neck but clinically appears more violaceous than the lesion seen in our patient.¹⁰ Paracoccidioidomycosis may form ulcerated papulonodules or plaques, especially around the nose and mouth. In many of these cases, lesions develop from contiguous lesions of the oral mucosa; therefore, the presence of oral lesions will help distinguish this infectious entity from cutaneous metastasis. Multiple lesions usually are identified when there is hematogenous dissemination.¹¹ Mycosis fungoides is a subtype of cutaneous T-cell lymphoma and is characterized by multiple patches, plaques, and nodules on sun-protected areas. Involvement of the head and neck is not common, except in the folliculotropic subtype, which has a separate and distinct clinical morphology.¹²

The development of signet ring morphology from an adenocarcinoma can be attributed to the activation of phosphatidylinositol 3-kinase (PI3K), which leads to downstream activation of mitogen-activated protein kinase (MAPK) and the subsequent loss of intercellular tight junctions. The mucin 4 gene, MUC4, also is upregulated by PI3K activation and possesses antiapoptotic and mitogenic effects in addition to its mucin secretory function.¹³

The neoplastic cells in SRCAs stain positive for mucicarmine, Alcian blue, and periodic acid–Schiff, which highlights the mucinous component of the cells.⁷ Immunohistochemical stains with CK7, CK20, AE1/AE3, and epithelial membrane antigen can be implemented to confirm an epithelial origin of the primary cancer.^7,13 CK20 is a low-molecular-weight cytokeratin normally expressed by Merkel cells and by the epithelium of the gastrointestinal tract and urothelium, whereas CK7 expression typically is expressed in the lungs, ovaries, endometrium, and breasts, but not in the lower gastrointestinal tract.¹⁴ Differentiating primary cutaneous adenocarcinoma from cutaneous metastasis can be accomplished with a thorough clinical history; however, p63 positivity supports a primary cutaneous lesion and may be useful in certain situations.⁷ CDX2 stains can be utilized to aid in localizing the primary neoplasm when it is unknown, and when positive, it suggests a lower gastrointestinal tract origin. However, special AT-rich sequence-binding protein 2 (SATB2) recently has been proposed as a replacement immunohistochemical marker for CDX2, as it has greater specificity for SRCA of the lower gastrointestinal tract.¹⁵ Benign entities with signet ring cell morphology are difficult to distinguish from SRCA; however, malignant lesions are more likely to demonstrate an infiltrative growth pattern, frequent mitotic figures, and apoptosis. Immunohistochemistry also can be utilized to support the diagnosis of benign proliferation with signet ring morphology, as benign lesions often will demonstrate E-cadherin positivity and negativity for p53 and Ki-67.¹³

Cutaneous metastasis usually correlates to advanced disease and generally indicates a worse prognosis.¹³ Signet ring cell morphology in both gastric and colorectal cancer portends a poor prognosis, and there is a lower overall survival in patients with these malignancies compared to cancers of the same organ with non–signet ring cell morphology.^4,8

The Diagnosis: Cutaneous Metastasis

A shave biopsy of the lip revealed a diffuse cellular infiltrate filling the superficial and deep dermis (Figure 1A). Morphologically, the cells had abundant clear cytoplasm with eccentrically located, pleomorphic, hyperchromatic nuclei with occasional prominent nucleoli (Figure 1B). The cells stained positive for AE1/ AE3 on immunohistochemistry (Figure 2). A punch biopsy of the nodule in the right axillary vault revealed a morphologically similar proliferation of cells. A colonoscopy revealed a completely obstructing circumferential mass in the distal ascending colon. A biopsy of the mass confirmed invasive adenocarcinoma, supporting a diagnosis of cutaneous metastases from adenocarcinoma of the colon. The patient underwent resection of the lip tumor and started multiagent chemotherapy for his newly diagnosed stage IV adenocarcinoma of the colon. The patient died, despite therapy.

Cutaneous metastasis from solid malignancies is uncommon, as only 1.3% of them exhibit cutaneous manifestations at presentation.¹ Cutaneous metastasis from signet ring cell adenocarcinoma (SRCA) of the colon is uncommon, and cutaneous metastasis of colorectal SRCA rarely precedes the diagnosis of the primary lesion.² Among the colorectal cancers that metastasize to the skin, metastasis to the face occurs in only 0.5% of patients.³

Signet ring cell adenocarcinomas are poorly differentiated adenocarcinomas histologically characterized by the neoplastic cells’ circular to ovoid appearance with a flattened top.^4,5 This distinctive shape is from the displacement of the nucleus to the periphery of the cell due to the accumulation of intracytoplasmic mucin.⁴ Classically, malignancies are characterized as an SRCA if more than 50% of the cells have a signet ring cell morphology; if the signet ring cells comprise less than 50% of the neoplasm, the tumor is designated as an adenocarcinoma with signet ring morphology.⁴ The most common cause of cutaneous metastasis with signet ring morphology is gastric cancer, while colorectal carcinoma is less common.1 Colorectal SRCAs usually are found in the right colon or the rectum in comparison to other colonic sites.⁶

Clinically, cutaneous metastasis can present in a variety of ways. The most common presentation is nodular lesions that may coalesce to become zosteriform in configuration or lesions that mimic inflammatory dermatoses.⁷ Cutaneous metastasis is more common in breast and lung cancer, and when it occurs secondary to colorectal cancer, cutaneous metastasis rarely predates the detection of the primary neoplasm.²

The clinical appearance of metastasis is not specific and can mimic many entities⁸; therefore, a high index of suspicion must be employed when managing patients, even those without a history of internal malignancy. In our patient, the smooth nodular lesion appeared similar to a basal cell carcinoma; however, basal cell carcinomas appear more pearly, and arborizing telangiectasia often is seen.⁹ Merkel cell carcinoma is common on sundamaged skin of the head and neck but clinically appears more violaceous than the lesion seen in our patient.¹⁰ Paracoccidioidomycosis may form ulcerated papulonodules or plaques, especially around the nose and mouth. In many of these cases, lesions develop from contiguous lesions of the oral mucosa; therefore, the presence of oral lesions will help distinguish this infectious entity from cutaneous metastasis. Multiple lesions usually are identified when there is hematogenous dissemination.¹¹ Mycosis fungoides is a subtype of cutaneous T-cell lymphoma and is characterized by multiple patches, plaques, and nodules on sun-protected areas. Involvement of the head and neck is not common, except in the folliculotropic subtype, which has a separate and distinct clinical morphology.¹²

The development of signet ring morphology from an adenocarcinoma can be attributed to the activation of phosphatidylinositol 3-kinase (PI3K), which leads to downstream activation of mitogen-activated protein kinase (MAPK) and the subsequent loss of intercellular tight junctions. The mucin 4 gene, MUC4, also is upregulated by PI3K activation and possesses antiapoptotic and mitogenic effects in addition to its mucin secretory function.¹³

The neoplastic cells in SRCAs stain positive for mucicarmine, Alcian blue, and periodic acid–Schiff, which highlights the mucinous component of the cells.⁷ Immunohistochemical stains with CK7, CK20, AE1/AE3, and epithelial membrane antigen can be implemented to confirm an epithelial origin of the primary cancer.^7,13 CK20 is a low-molecular-weight cytokeratin normally expressed by Merkel cells and by the epithelium of the gastrointestinal tract and urothelium, whereas CK7 expression typically is expressed in the lungs, ovaries, endometrium, and breasts, but not in the lower gastrointestinal tract.¹⁴ Differentiating primary cutaneous adenocarcinoma from cutaneous metastasis can be accomplished with a thorough clinical history; however, p63 positivity supports a primary cutaneous lesion and may be useful in certain situations.⁷ CDX2 stains can be utilized to aid in localizing the primary neoplasm when it is unknown, and when positive, it suggests a lower gastrointestinal tract origin. However, special AT-rich sequence-binding protein 2 (SATB2) recently has been proposed as a replacement immunohistochemical marker for CDX2, as it has greater specificity for SRCA of the lower gastrointestinal tract.¹⁵ Benign entities with signet ring cell morphology are difficult to distinguish from SRCA; however, malignant lesions are more likely to demonstrate an infiltrative growth pattern, frequent mitotic figures, and apoptosis. Immunohistochemistry also can be utilized to support the diagnosis of benign proliferation with signet ring morphology, as benign lesions often will demonstrate E-cadherin positivity and negativity for p53 and Ki-67.¹³

Cutaneous metastasis usually correlates to advanced disease and generally indicates a worse prognosis.¹³ Signet ring cell morphology in both gastric and colorectal cancer portends a poor prognosis, and there is a lower overall survival in patients with these malignancies compared to cancers of the same organ with non–signet ring cell morphology.^4,8

The Diagnosis: Cutaneous Metastasis

A shave biopsy of the lip revealed a diffuse cellular infiltrate filling the superficial and deep dermis (Figure 1A). Morphologically, the cells had abundant clear cytoplasm with eccentrically located, pleomorphic, hyperchromatic nuclei with occasional prominent nucleoli (Figure 1B). The cells stained positive for AE1/ AE3 on immunohistochemistry (Figure 2). A punch biopsy of the nodule in the right axillary vault revealed a morphologically similar proliferation of cells. A colonoscopy revealed a completely obstructing circumferential mass in the distal ascending colon. A biopsy of the mass confirmed invasive adenocarcinoma, supporting a diagnosis of cutaneous metastases from adenocarcinoma of the colon. The patient underwent resection of the lip tumor and started multiagent chemotherapy for his newly diagnosed stage IV adenocarcinoma of the colon. The patient died, despite therapy.

Cutaneous metastasis from solid malignancies is uncommon, as only 1.3% of them exhibit cutaneous manifestations at presentation.¹ Cutaneous metastasis from signet ring cell adenocarcinoma (SRCA) of the colon is uncommon, and cutaneous metastasis of colorectal SRCA rarely precedes the diagnosis of the primary lesion.² Among the colorectal cancers that metastasize to the skin, metastasis to the face occurs in only 0.5% of patients.³

Signet ring cell adenocarcinomas are poorly differentiated adenocarcinomas histologically characterized by the neoplastic cells’ circular to ovoid appearance with a flattened top.^4,5 This distinctive shape is from the displacement of the nucleus to the periphery of the cell due to the accumulation of intracytoplasmic mucin.⁴ Classically, malignancies are characterized as an SRCA if more than 50% of the cells have a signet ring cell morphology; if the signet ring cells comprise less than 50% of the neoplasm, the tumor is designated as an adenocarcinoma with signet ring morphology.⁴ The most common cause of cutaneous metastasis with signet ring morphology is gastric cancer, while colorectal carcinoma is less common.1 Colorectal SRCAs usually are found in the right colon or the rectum in comparison to other colonic sites.⁶

Clinically, cutaneous metastasis can present in a variety of ways. The most common presentation is nodular lesions that may coalesce to become zosteriform in configuration or lesions that mimic inflammatory dermatoses.⁷ Cutaneous metastasis is more common in breast and lung cancer, and when it occurs secondary to colorectal cancer, cutaneous metastasis rarely predates the detection of the primary neoplasm.²

The clinical appearance of metastasis is not specific and can mimic many entities⁸; therefore, a high index of suspicion must be employed when managing patients, even those without a history of internal malignancy. In our patient, the smooth nodular lesion appeared similar to a basal cell carcinoma; however, basal cell carcinomas appear more pearly, and arborizing telangiectasia often is seen.⁹ Merkel cell carcinoma is common on sundamaged skin of the head and neck but clinically appears more violaceous than the lesion seen in our patient.¹⁰ Paracoccidioidomycosis may form ulcerated papulonodules or plaques, especially around the nose and mouth. In many of these cases, lesions develop from contiguous lesions of the oral mucosa; therefore, the presence of oral lesions will help distinguish this infectious entity from cutaneous metastasis. Multiple lesions usually are identified when there is hematogenous dissemination.¹¹ Mycosis fungoides is a subtype of cutaneous T-cell lymphoma and is characterized by multiple patches, plaques, and nodules on sun-protected areas. Involvement of the head and neck is not common, except in the folliculotropic subtype, which has a separate and distinct clinical morphology.¹²

The development of signet ring morphology from an adenocarcinoma can be attributed to the activation of phosphatidylinositol 3-kinase (PI3K), which leads to downstream activation of mitogen-activated protein kinase (MAPK) and the subsequent loss of intercellular tight junctions. The mucin 4 gene, MUC4, also is upregulated by PI3K activation and possesses antiapoptotic and mitogenic effects in addition to its mucin secretory function.¹³

The neoplastic cells in SRCAs stain positive for mucicarmine, Alcian blue, and periodic acid–Schiff, which highlights the mucinous component of the cells.⁷ Immunohistochemical stains with CK7, CK20, AE1/AE3, and epithelial membrane antigen can be implemented to confirm an epithelial origin of the primary cancer.^7,13 CK20 is a low-molecular-weight cytokeratin normally expressed by Merkel cells and by the epithelium of the gastrointestinal tract and urothelium, whereas CK7 expression typically is expressed in the lungs, ovaries, endometrium, and breasts, but not in the lower gastrointestinal tract.¹⁴ Differentiating primary cutaneous adenocarcinoma from cutaneous metastasis can be accomplished with a thorough clinical history; however, p63 positivity supports a primary cutaneous lesion and may be useful in certain situations.⁷ CDX2 stains can be utilized to aid in localizing the primary neoplasm when it is unknown, and when positive, it suggests a lower gastrointestinal tract origin. However, special AT-rich sequence-binding protein 2 (SATB2) recently has been proposed as a replacement immunohistochemical marker for CDX2, as it has greater specificity for SRCA of the lower gastrointestinal tract.¹⁵ Benign entities with signet ring cell morphology are difficult to distinguish from SRCA; however, malignant lesions are more likely to demonstrate an infiltrative growth pattern, frequent mitotic figures, and apoptosis. Immunohistochemistry also can be utilized to support the diagnosis of benign proliferation with signet ring morphology, as benign lesions often will demonstrate E-cadherin positivity and negativity for p53 and Ki-67.¹³

Cutaneous metastasis usually correlates to advanced disease and generally indicates a worse prognosis.¹³ Signet ring cell morphology in both gastric and colorectal cancer portends a poor prognosis, and there is a lower overall survival in patients with these malignancies compared to cancers of the same organ with non–signet ring cell morphology.^4,8

The Diagnosis: Hypopigmented Mycosis Fungoides

Histopathology showed an atypical lymphoid infiltrate with expanded cytoplasm and hyperchromatic nuclei of irregular contours in the dermoepidermal junction (Figure 1). Immunohistochemical stains of atypical lymphocytes demonstrated the presence of CD3, CD8, and CD5, as well as the absence of CD7 and CD4 lymphocytes (Figure 2). The T-cell γ rearrangement showed polyclonal lymphocytes with 5% tumor cells. The histologic and clinical findings along with our patient’s medical history led to a diagnosis of stage IA (<10% body surface area involvement) hypopigmented mycosis fungoides (hMF).¹ Our patient was treated with triamcinolone cream 0.1%; she noted an improvement in her symptoms at 2-month follow-up.

Hypopigmented MF is an uncommon manifestation of MF with unknown prevalence and incidence rates. Mycosis fungoides is considered the most common subtype of cutaneous T-cell lymphoma that classically presents as a chronic, indolent, hypopigmented or depigmented macule or patch, commonly with scaling, in sunprotected areas such as the trunk and proximal arms and legs. It predominantly affects younger adults with darker skin tones and may be present in the pediatric population within the first decade of life.¹ Classically, MF affects White patients aged 55 to 60 years. Disease progression is slow, with an incidence rate of 10% of tumor or extracutaneous involvement in the early stages of disease. A lack of specificity on the clinical and histopathologic findings in the initial stage often contributes to the diagnostic delay of hMF. As seen in our patient, this disease can be misdiagnosed as tinea versicolor, postinflammatory hypopigmentation, vitiligo, pityriasis alba, subcutaneous lupus erythematosus, or Hansen disease due to prolonged hypopigmented lesions.² The clinical findings and histopathologic results including immunohistochemistry confirmed the diagnosis of hMF and ruled out pityriasis alba, postinflammatory hypopigmentation, subcutaneous lupus erythematosus, and vitiligo.

The etiology and pathophysiology of hMF are not fully understood; however, it is hypothesized that melanocyte degeneration, abnormal melanogenesis, and disturbance of melanosome transfer result from the clonal expansion of T helper memory cells. T-cell dyscrasia has been reported to evolve into hMF during etanercept therapy.³ Clinically, hMF presents as hypopigmented papulosquamous, eczematous, or erythrodermic patches, plaques, and tumors with poorly defined atrophied borders. Multiple biopsies of steroid-naive lesions are needed for the diagnosis, as the initial hMF histologic finding cannot be specific for diagnostic confirmation. Common histopathologic findings include a bandlike lymphocytic infiltrate with epidermotropism, intraepidermal nests of atypical cells, or cerebriform nuclei lymphocytes on hematoxylin and eosin staining. In comparison to classical MF epidermotropism, CD4− and CD8+ atypical cells aid in the diagnosis of hMF. Although hMF carries a good prognosis and a benign clinical course,⁴ full-body computed tomography or positron emission tomography/computed tomography as well as laboratory analysis for lactate dehydrogenase should be pursued if lymphadenopathy, systemic symptoms, or advancedstage hMF are present.

Treatment of hMF depends on the disease stage. Psoralen plus UVA and narrowband UVB can be utilized for the initial stages with a relatively fast response and remission of lesions as early as the first 2 months of treatment. In addition to phototherapy, stage IA to IIA mycosis fungoides with localized skin lesions can benefit from topical steroids, topical retinoids, imiquimod, nitrogen mustard, and carmustine. For advanced stages of mycosis fungoides, combination therapy consisting of psoralen plus UVA with an oral retinoid, interferon alfa, and systemic chemotherapy commonly are prescribed. Maintenance therapy is used for prolonging remission; however, long-term phototherapy is not recommended due to the risk for skin cancer. Unfortunately, hMF requires long-term treatment due to its waxing and waning course, and recurrence may occur after complete resolution.⁵

The Diagnosis: Hypopigmented Mycosis Fungoides

Histopathology showed an atypical lymphoid infiltrate with expanded cytoplasm and hyperchromatic nuclei of irregular contours in the dermoepidermal junction (Figure 1). Immunohistochemical stains of atypical lymphocytes demonstrated the presence of CD3, CD8, and CD5, as well as the absence of CD7 and CD4 lymphocytes (Figure 2). The T-cell γ rearrangement showed polyclonal lymphocytes with 5% tumor cells. The histologic and clinical findings along with our patient’s medical history led to a diagnosis of stage IA (<10% body surface area involvement) hypopigmented mycosis fungoides (hMF).¹ Our patient was treated with triamcinolone cream 0.1%; she noted an improvement in her symptoms at 2-month follow-up.

Hypopigmented MF is an uncommon manifestation of MF with unknown prevalence and incidence rates. Mycosis fungoides is considered the most common subtype of cutaneous T-cell lymphoma that classically presents as a chronic, indolent, hypopigmented or depigmented macule or patch, commonly with scaling, in sunprotected areas such as the trunk and proximal arms and legs. It predominantly affects younger adults with darker skin tones and may be present in the pediatric population within the first decade of life.¹ Classically, MF affects White patients aged 55 to 60 years. Disease progression is slow, with an incidence rate of 10% of tumor or extracutaneous involvement in the early stages of disease. A lack of specificity on the clinical and histopathologic findings in the initial stage often contributes to the diagnostic delay of hMF. As seen in our patient, this disease can be misdiagnosed as tinea versicolor, postinflammatory hypopigmentation, vitiligo, pityriasis alba, subcutaneous lupus erythematosus, or Hansen disease due to prolonged hypopigmented lesions.² The clinical findings and histopathologic results including immunohistochemistry confirmed the diagnosis of hMF and ruled out pityriasis alba, postinflammatory hypopigmentation, subcutaneous lupus erythematosus, and vitiligo.

The etiology and pathophysiology of hMF are not fully understood; however, it is hypothesized that melanocyte degeneration, abnormal melanogenesis, and disturbance of melanosome transfer result from the clonal expansion of T helper memory cells. T-cell dyscrasia has been reported to evolve into hMF during etanercept therapy.³ Clinically, hMF presents as hypopigmented papulosquamous, eczematous, or erythrodermic patches, plaques, and tumors with poorly defined atrophied borders. Multiple biopsies of steroid-naive lesions are needed for the diagnosis, as the initial hMF histologic finding cannot be specific for diagnostic confirmation. Common histopathologic findings include a bandlike lymphocytic infiltrate with epidermotropism, intraepidermal nests of atypical cells, or cerebriform nuclei lymphocytes on hematoxylin and eosin staining. In comparison to classical MF epidermotropism, CD4− and CD8+ atypical cells aid in the diagnosis of hMF. Although hMF carries a good prognosis and a benign clinical course,⁴ full-body computed tomography or positron emission tomography/computed tomography as well as laboratory analysis for lactate dehydrogenase should be pursued if lymphadenopathy, systemic symptoms, or advancedstage hMF are present.

Treatment of hMF depends on the disease stage. Psoralen plus UVA and narrowband UVB can be utilized for the initial stages with a relatively fast response and remission of lesions as early as the first 2 months of treatment. In addition to phototherapy, stage IA to IIA mycosis fungoides with localized skin lesions can benefit from topical steroids, topical retinoids, imiquimod, nitrogen mustard, and carmustine. For advanced stages of mycosis fungoides, combination therapy consisting of psoralen plus UVA with an oral retinoid, interferon alfa, and systemic chemotherapy commonly are prescribed. Maintenance therapy is used for prolonging remission; however, long-term phototherapy is not recommended due to the risk for skin cancer. Unfortunately, hMF requires long-term treatment due to its waxing and waning course, and recurrence may occur after complete resolution.⁵

The Diagnosis: Hypopigmented Mycosis Fungoides

Histopathology showed an atypical lymphoid infiltrate with expanded cytoplasm and hyperchromatic nuclei of irregular contours in the dermoepidermal junction (Figure 1). Immunohistochemical stains of atypical lymphocytes demonstrated the presence of CD3, CD8, and CD5, as well as the absence of CD7 and CD4 lymphocytes (Figure 2). The T-cell γ rearrangement showed polyclonal lymphocytes with 5% tumor cells. The histologic and clinical findings along with our patient’s medical history led to a diagnosis of stage IA (<10% body surface area involvement) hypopigmented mycosis fungoides (hMF).¹ Our patient was treated with triamcinolone cream 0.1%; she noted an improvement in her symptoms at 2-month follow-up.

Hypopigmented MF is an uncommon manifestation of MF with unknown prevalence and incidence rates. Mycosis fungoides is considered the most common subtype of cutaneous T-cell lymphoma that classically presents as a chronic, indolent, hypopigmented or depigmented macule or patch, commonly with scaling, in sunprotected areas such as the trunk and proximal arms and legs. It predominantly affects younger adults with darker skin tones and may be present in the pediatric population within the first decade of life.¹ Classically, MF affects White patients aged 55 to 60 years. Disease progression is slow, with an incidence rate of 10% of tumor or extracutaneous involvement in the early stages of disease. A lack of specificity on the clinical and histopathologic findings in the initial stage often contributes to the diagnostic delay of hMF. As seen in our patient, this disease can be misdiagnosed as tinea versicolor, postinflammatory hypopigmentation, vitiligo, pityriasis alba, subcutaneous lupus erythematosus, or Hansen disease due to prolonged hypopigmented lesions.² The clinical findings and histopathologic results including immunohistochemistry confirmed the diagnosis of hMF and ruled out pityriasis alba, postinflammatory hypopigmentation, subcutaneous lupus erythematosus, and vitiligo.

The etiology and pathophysiology of hMF are not fully understood; however, it is hypothesized that melanocyte degeneration, abnormal melanogenesis, and disturbance of melanosome transfer result from the clonal expansion of T helper memory cells. T-cell dyscrasia has been reported to evolve into hMF during etanercept therapy.³ Clinically, hMF presents as hypopigmented papulosquamous, eczematous, or erythrodermic patches, plaques, and tumors with poorly defined atrophied borders. Multiple biopsies of steroid-naive lesions are needed for the diagnosis, as the initial hMF histologic finding cannot be specific for diagnostic confirmation. Common histopathologic findings include a bandlike lymphocytic infiltrate with epidermotropism, intraepidermal nests of atypical cells, or cerebriform nuclei lymphocytes on hematoxylin and eosin staining. In comparison to classical MF epidermotropism, CD4− and CD8+ atypical cells aid in the diagnosis of hMF. Although hMF carries a good prognosis and a benign clinical course,⁴ full-body computed tomography or positron emission tomography/computed tomography as well as laboratory analysis for lactate dehydrogenase should be pursued if lymphadenopathy, systemic symptoms, or advancedstage hMF are present.

Treatment of hMF depends on the disease stage. Psoralen plus UVA and narrowband UVB can be utilized for the initial stages with a relatively fast response and remission of lesions as early as the first 2 months of treatment. In addition to phototherapy, stage IA to IIA mycosis fungoides with localized skin lesions can benefit from topical steroids, topical retinoids, imiquimod, nitrogen mustard, and carmustine. For advanced stages of mycosis fungoides, combination therapy consisting of psoralen plus UVA with an oral retinoid, interferon alfa, and systemic chemotherapy commonly are prescribed. Maintenance therapy is used for prolonging remission; however, long-term phototherapy is not recommended due to the risk for skin cancer. Unfortunately, hMF requires long-term treatment due to its waxing and waning course, and recurrence may occur after complete resolution.⁵

THE DIAGNOSIS: Neutrophilic Eccrine Hidradenitis

A biopsy from the left preauricular cheek demonstrated dermal neutrophilic inflammation around eccrine coils with focal necrosis (Figure). No notable diffuse dermal neutrophilic infiltrate was present, ruling out Sweet syndrome, and no notable interstitial neutrophilic infiltrate was present, making cellulitis and erysipelas less likely; panculture of tissue also was negative.^1,2 Atypical cells in the deep dermis were positive for CD163 and negative for CD117, CD34, CD123, and myeloperoxidase, consistent with a diagnosis of neutrophilic eccrine hidradenitis (NEH) and reactive histiocytes.³ Treatment with oral prednisone resulted in rapid improvement of symptoms.

Neutrophilic eccrine hidradenitis is a rare reactive neutrophilic dermatosis characterized by eccrine gland involvement. This benign and self-limited condition presents as asymmetric erythematous papules and plaques.² Among 8 granulocytopenic patients with neutrophilic dermatoses, 5 were diagnosed with NEH.⁴ Although first identified in 1982, NEH remains poorly understood.² Initial theories suggested that NEH developed due to cytotoxic substances secreted in sweat glands causing necrosis and neutrophil chemotaxis; however, chemotherapy exposure cannot be linked to every case of NEH. Neutrophilic eccrine hidradenitis can be extremely difficult to differentiate clinically from conditions such as cellulitis and Sweet syndrome.

A patient history can be helpful in identifying triggering factors. Neutrophilic eccrine hidradenitis most commonly is associated with malignant, drug-induced, or infectious triggers, while Sweet syndrome has a broad range of associations including infections, vaccines, inflammatory bowel disease, pregnancy, malignancy, and drug-induced etiologies (Table).¹ On average, NEH presents 10 days after chemotherapy induction, with 70% of cases presenting after the first chemotherapy cycle.⁵ Bacterial cellulitis or erysipelas have an infectious etiology, and patients may report symptoms such as fever, chills, or malaise. Immunosuppressed patients are at greater risk for infection; therefore, clinical signs of infection in a granulocytopenic patient should be addressed urgently.

Physical examination may have limited value in differentiating between these diagnoses, as neutrophilic dermatoses notoriously mimic infection. Cutaneous lesions can appear as pruritic or tender erythematous plaques, papules, or nodules in these conditions, though cellulitis and erysipelas tend to be unilateral and may have associated purulence or inflamed skin lymphatics. Given the potential for misdiagnosis, approaching patients with a broad differential can be helpful. In our patient, the differential diagnosis included Sweet syndrome, NEH, bacterial cellulitis, erysipelas, leukemia cutis, sarcoid, and eosinophilic cellulitis.

Leukemia cutis refers to the infiltration of neoplastic leukocytes in the skin and often occurs in patients with peripheral leukemia, most often acute myeloid leukemia or chronic lymphocytic leukemia. Patients with leukemia cutis often have a worse prognosis, as this finding signifies extramedullary spread of disease.⁶ Clinically, lesions can appear similar to those seen in our patient, though they typically are not symptomatic, can be nodular, tend to exhibit a violaceous hue, and occasionally may be hemorrhagic. Wells syndrome (also known as eosinophilic cellulitis) is an inflammatory dermatosis that presents as painful or pruritic, edematous and erythematous plaques.^7,8 A green hue on resolution is present in some cases and may help clinicians differentiate this disease from mimickers.⁷ Often, eosinophilic cellulitis is misdiagnosed as bacterial cellulitis and treated with antibiotics. The presence of systemic symptoms such as fever or arthralgia is more typical of bacterial cellulitis, erysipelas, eosinophilic cellulitis, or Sweet syndrome than of NEH.¹ Additionally, inflammatory markers (ie, C-reactive protein) and white blood cell counts tend to be elevated in bacterial cellulitis and Sweet syndrome, while leukopenia often is seen in NEH.

Histopathology is crucial in distinguishing these disease etiologies. Neutrophilic eccrine hidradenitis is diagnosed by the characteristic neutrophilic infiltrate and necrosis surrounding eccrine glands and coils. There also may be occasional intraductal abscesses and syringosquamous metaplasia of the sweat glands along with fibrosis of the adjacent dermis. In contrast, histologic sections of Sweet syndrome show numerous mature neutrophils infiltrating the dermis with marked papillary dermal edema. The histopathology of bacterial cellulitis and erysipelas is less specific, but common features include dermal edema, lymphatic dilation, and a diffuse neutrophilic infiltrate surrounding blood vessels. Pathogenic organisms may be seen on histopathology but are not required for the diagnosis of bacterial cellulitis or erysipelas.² Additionally, blood and tissue culture can assist in identification of both the source of infection and the causative organism, but cultures may not always be positive. 

Comparatively, the histopathologic features of eosinophilic cellulitis include dermal edema, eosinophilic infiltration, and flame figures that form when eosinophils degranulate and coat collagen fibers with major basic protein. Flame figures are characteristic but not pathognomonic for eosinophilic cellulitis.⁷ The histopathology of leukemia cutis varies based on the leukemia classification; generally, in acute myeloid leukemia the infiltrate is composed of neoplastic cells in the early stages of development that are positive for myeloid markers such as myeloperoxidase. Atypical and immature granulocytes within the leukocytic infiltrate differentiate this condition from the other diagnoses. Treatment may entail chemotherapy or radiotherapy, and this diagnosis generally carries the worst prognosis of all the conditions in the differential.⁶

Differentiating between these conditions is important in guiding treatment, especially in patients with febrile neutropenia. Unnecessary steroids in immunosuppressed patients can be dangerous, especially if the patient has an infection such as bacterial cellulitis. Furthermore, unwarranted antibiotic use for noninfectious conditions may expose patients to substantial side effects and not improve the condition. Neutrophilic eccrine hidradenitis typically is self-limited and treated symptomatically with systemic corticosteroids and nonsteroidal anti-inflammatory drugs.³ Sweet syndrome often requires a longer course of oral steroids. Leukemia cutis worsens as the leukemia advances, and treatment of the underlying malignancy is the most effective treatment.⁹

Early and accurate recognition of the diagnosis can prevent harmful diagnostic delay, unnecessary antibiotic use, or extended steroid taper in neutropenic patients. Appreciating the differences between these diagnoses can assist clinicians in investigating and tailoring a broad differential to specific patient presentations, which is especially critical when considering common mimickers for life-threatening conditions.

THE DIAGNOSIS: Neutrophilic Eccrine Hidradenitis

A biopsy from the left preauricular cheek demonstrated dermal neutrophilic inflammation around eccrine coils with focal necrosis (Figure). No notable diffuse dermal neutrophilic infiltrate was present, ruling out Sweet syndrome, and no notable interstitial neutrophilic infiltrate was present, making cellulitis and erysipelas less likely; panculture of tissue also was negative.^1,2 Atypical cells in the deep dermis were positive for CD163 and negative for CD117, CD34, CD123, and myeloperoxidase, consistent with a diagnosis of neutrophilic eccrine hidradenitis (NEH) and reactive histiocytes.³ Treatment with oral prednisone resulted in rapid improvement of symptoms.

Neutrophilic eccrine hidradenitis is a rare reactive neutrophilic dermatosis characterized by eccrine gland involvement. This benign and self-limited condition presents as asymmetric erythematous papules and plaques.² Among 8 granulocytopenic patients with neutrophilic dermatoses, 5 were diagnosed with NEH.⁴ Although first identified in 1982, NEH remains poorly understood.² Initial theories suggested that NEH developed due to cytotoxic substances secreted in sweat glands causing necrosis and neutrophil chemotaxis; however, chemotherapy exposure cannot be linked to every case of NEH. Neutrophilic eccrine hidradenitis can be extremely difficult to differentiate clinically from conditions such as cellulitis and Sweet syndrome.

A patient history can be helpful in identifying triggering factors. Neutrophilic eccrine hidradenitis most commonly is associated with malignant, drug-induced, or infectious triggers, while Sweet syndrome has a broad range of associations including infections, vaccines, inflammatory bowel disease, pregnancy, malignancy, and drug-induced etiologies (Table).¹ On average, NEH presents 10 days after chemotherapy induction, with 70% of cases presenting after the first chemotherapy cycle.⁵ Bacterial cellulitis or erysipelas have an infectious etiology, and patients may report symptoms such as fever, chills, or malaise. Immunosuppressed patients are at greater risk for infection; therefore, clinical signs of infection in a granulocytopenic patient should be addressed urgently.

Physical examination may have limited value in differentiating between these diagnoses, as neutrophilic dermatoses notoriously mimic infection. Cutaneous lesions can appear as pruritic or tender erythematous plaques, papules, or nodules in these conditions, though cellulitis and erysipelas tend to be unilateral and may have associated purulence or inflamed skin lymphatics. Given the potential for misdiagnosis, approaching patients with a broad differential can be helpful. In our patient, the differential diagnosis included Sweet syndrome, NEH, bacterial cellulitis, erysipelas, leukemia cutis, sarcoid, and eosinophilic cellulitis.

Leukemia cutis refers to the infiltration of neoplastic leukocytes in the skin and often occurs in patients with peripheral leukemia, most often acute myeloid leukemia or chronic lymphocytic leukemia. Patients with leukemia cutis often have a worse prognosis, as this finding signifies extramedullary spread of disease.⁶ Clinically, lesions can appear similar to those seen in our patient, though they typically are not symptomatic, can be nodular, tend to exhibit a violaceous hue, and occasionally may be hemorrhagic. Wells syndrome (also known as eosinophilic cellulitis) is an inflammatory dermatosis that presents as painful or pruritic, edematous and erythematous plaques.^7,8 A green hue on resolution is present in some cases and may help clinicians differentiate this disease from mimickers.⁷ Often, eosinophilic cellulitis is misdiagnosed as bacterial cellulitis and treated with antibiotics. The presence of systemic symptoms such as fever or arthralgia is more typical of bacterial cellulitis, erysipelas, eosinophilic cellulitis, or Sweet syndrome than of NEH.¹ Additionally, inflammatory markers (ie, C-reactive protein) and white blood cell counts tend to be elevated in bacterial cellulitis and Sweet syndrome, while leukopenia often is seen in NEH.

Histopathology is crucial in distinguishing these disease etiologies. Neutrophilic eccrine hidradenitis is diagnosed by the characteristic neutrophilic infiltrate and necrosis surrounding eccrine glands and coils. There also may be occasional intraductal abscesses and syringosquamous metaplasia of the sweat glands along with fibrosis of the adjacent dermis. In contrast, histologic sections of Sweet syndrome show numerous mature neutrophils infiltrating the dermis with marked papillary dermal edema. The histopathology of bacterial cellulitis and erysipelas is less specific, but common features include dermal edema, lymphatic dilation, and a diffuse neutrophilic infiltrate surrounding blood vessels. Pathogenic organisms may be seen on histopathology but are not required for the diagnosis of bacterial cellulitis or erysipelas.² Additionally, blood and tissue culture can assist in identification of both the source of infection and the causative organism, but cultures may not always be positive. 

Comparatively, the histopathologic features of eosinophilic cellulitis include dermal edema, eosinophilic infiltration, and flame figures that form when eosinophils degranulate and coat collagen fibers with major basic protein. Flame figures are characteristic but not pathognomonic for eosinophilic cellulitis.⁷ The histopathology of leukemia cutis varies based on the leukemia classification; generally, in acute myeloid leukemia the infiltrate is composed of neoplastic cells in the early stages of development that are positive for myeloid markers such as myeloperoxidase. Atypical and immature granulocytes within the leukocytic infiltrate differentiate this condition from the other diagnoses. Treatment may entail chemotherapy or radiotherapy, and this diagnosis generally carries the worst prognosis of all the conditions in the differential.⁶

Differentiating between these conditions is important in guiding treatment, especially in patients with febrile neutropenia. Unnecessary steroids in immunosuppressed patients can be dangerous, especially if the patient has an infection such as bacterial cellulitis. Furthermore, unwarranted antibiotic use for noninfectious conditions may expose patients to substantial side effects and not improve the condition. Neutrophilic eccrine hidradenitis typically is self-limited and treated symptomatically with systemic corticosteroids and nonsteroidal anti-inflammatory drugs.³ Sweet syndrome often requires a longer course of oral steroids. Leukemia cutis worsens as the leukemia advances, and treatment of the underlying malignancy is the most effective treatment.⁹

Early and accurate recognition of the diagnosis can prevent harmful diagnostic delay, unnecessary antibiotic use, or extended steroid taper in neutropenic patients. Appreciating the differences between these diagnoses can assist clinicians in investigating and tailoring a broad differential to specific patient presentations, which is especially critical when considering common mimickers for life-threatening conditions.

THE DIAGNOSIS: Neutrophilic Eccrine Hidradenitis

A biopsy from the left preauricular cheek demonstrated dermal neutrophilic inflammation around eccrine coils with focal necrosis (Figure). No notable diffuse dermal neutrophilic infiltrate was present, ruling out Sweet syndrome, and no notable interstitial neutrophilic infiltrate was present, making cellulitis and erysipelas less likely; panculture of tissue also was negative.^1,2 Atypical cells in the deep dermis were positive for CD163 and negative for CD117, CD34, CD123, and myeloperoxidase, consistent with a diagnosis of neutrophilic eccrine hidradenitis (NEH) and reactive histiocytes.³ Treatment with oral prednisone resulted in rapid improvement of symptoms.

Neutrophilic eccrine hidradenitis is a rare reactive neutrophilic dermatosis characterized by eccrine gland involvement. This benign and self-limited condition presents as asymmetric erythematous papules and plaques.² Among 8 granulocytopenic patients with neutrophilic dermatoses, 5 were diagnosed with NEH.⁴ Although first identified in 1982, NEH remains poorly understood.² Initial theories suggested that NEH developed due to cytotoxic substances secreted in sweat glands causing necrosis and neutrophil chemotaxis; however, chemotherapy exposure cannot be linked to every case of NEH. Neutrophilic eccrine hidradenitis can be extremely difficult to differentiate clinically from conditions such as cellulitis and Sweet syndrome.

A patient history can be helpful in identifying triggering factors. Neutrophilic eccrine hidradenitis most commonly is associated with malignant, drug-induced, or infectious triggers, while Sweet syndrome has a broad range of associations including infections, vaccines, inflammatory bowel disease, pregnancy, malignancy, and drug-induced etiologies (Table).¹ On average, NEH presents 10 days after chemotherapy induction, with 70% of cases presenting after the first chemotherapy cycle.⁵ Bacterial cellulitis or erysipelas have an infectious etiology, and patients may report symptoms such as fever, chills, or malaise. Immunosuppressed patients are at greater risk for infection; therefore, clinical signs of infection in a granulocytopenic patient should be addressed urgently.

Physical examination may have limited value in differentiating between these diagnoses, as neutrophilic dermatoses notoriously mimic infection. Cutaneous lesions can appear as pruritic or tender erythematous plaques, papules, or nodules in these conditions, though cellulitis and erysipelas tend to be unilateral and may have associated purulence or inflamed skin lymphatics. Given the potential for misdiagnosis, approaching patients with a broad differential can be helpful. In our patient, the differential diagnosis included Sweet syndrome, NEH, bacterial cellulitis, erysipelas, leukemia cutis, sarcoid, and eosinophilic cellulitis.

Leukemia cutis refers to the infiltration of neoplastic leukocytes in the skin and often occurs in patients with peripheral leukemia, most often acute myeloid leukemia or chronic lymphocytic leukemia. Patients with leukemia cutis often have a worse prognosis, as this finding signifies extramedullary spread of disease.⁶ Clinically, lesions can appear similar to those seen in our patient, though they typically are not symptomatic, can be nodular, tend to exhibit a violaceous hue, and occasionally may be hemorrhagic. Wells syndrome (also known as eosinophilic cellulitis) is an inflammatory dermatosis that presents as painful or pruritic, edematous and erythematous plaques.^7,8 A green hue on resolution is present in some cases and may help clinicians differentiate this disease from mimickers.⁷ Often, eosinophilic cellulitis is misdiagnosed as bacterial cellulitis and treated with antibiotics. The presence of systemic symptoms such as fever or arthralgia is more typical of bacterial cellulitis, erysipelas, eosinophilic cellulitis, or Sweet syndrome than of NEH.¹ Additionally, inflammatory markers (ie, C-reactive protein) and white blood cell counts tend to be elevated in bacterial cellulitis and Sweet syndrome, while leukopenia often is seen in NEH.

Histopathology is crucial in distinguishing these disease etiologies. Neutrophilic eccrine hidradenitis is diagnosed by the characteristic neutrophilic infiltrate and necrosis surrounding eccrine glands and coils. There also may be occasional intraductal abscesses and syringosquamous metaplasia of the sweat glands along with fibrosis of the adjacent dermis. In contrast, histologic sections of Sweet syndrome show numerous mature neutrophils infiltrating the dermis with marked papillary dermal edema. The histopathology of bacterial cellulitis and erysipelas is less specific, but common features include dermal edema, lymphatic dilation, and a diffuse neutrophilic infiltrate surrounding blood vessels. Pathogenic organisms may be seen on histopathology but are not required for the diagnosis of bacterial cellulitis or erysipelas.² Additionally, blood and tissue culture can assist in identification of both the source of infection and the causative organism, but cultures may not always be positive. 

Comparatively, the histopathologic features of eosinophilic cellulitis include dermal edema, eosinophilic infiltration, and flame figures that form when eosinophils degranulate and coat collagen fibers with major basic protein. Flame figures are characteristic but not pathognomonic for eosinophilic cellulitis.⁷ The histopathology of leukemia cutis varies based on the leukemia classification; generally, in acute myeloid leukemia the infiltrate is composed of neoplastic cells in the early stages of development that are positive for myeloid markers such as myeloperoxidase. Atypical and immature granulocytes within the leukocytic infiltrate differentiate this condition from the other diagnoses. Treatment may entail chemotherapy or radiotherapy, and this diagnosis generally carries the worst prognosis of all the conditions in the differential.⁶

Differentiating between these conditions is important in guiding treatment, especially in patients with febrile neutropenia. Unnecessary steroids in immunosuppressed patients can be dangerous, especially if the patient has an infection such as bacterial cellulitis. Furthermore, unwarranted antibiotic use for noninfectious conditions may expose patients to substantial side effects and not improve the condition. Neutrophilic eccrine hidradenitis typically is self-limited and treated symptomatically with systemic corticosteroids and nonsteroidal anti-inflammatory drugs.³ Sweet syndrome often requires a longer course of oral steroids. Leukemia cutis worsens as the leukemia advances, and treatment of the underlying malignancy is the most effective treatment.⁹

Early and accurate recognition of the diagnosis can prevent harmful diagnostic delay, unnecessary antibiotic use, or extended steroid taper in neutropenic patients. Appreciating the differences between these diagnoses can assist clinicians in investigating and tailoring a broad differential to specific patient presentations, which is especially critical when considering common mimickers for life-threatening conditions.

The Diagnosis: Dominant Dystrophic Epidermolysis Bullosa

Blisters in a neonate may be caused by infectious, traumatic, autoimmune, or congenital etiologies. Biopsy findings correlated with clinical findings usually can establish a prompt diagnosis when the clinical diagnosis is uncertain. Direct immunofluorescence (DIF) as well as indirect immunofluorescence studies are useful when autoimmune blistering disease or congenital or heritable disorders of skin fragility are in the differential diagnosis. Many genetic abnormalities of skin fragility are associated with marked morbidity and mortality, and prompt diagnosis is essential to provide proper care. Our patient’s parents had no history of skin disorders, and there was no known family history of blistering disease or traumatic birth. A heritable disorder of skin fragility was still a top consideration because of the extensive blistering in the absence of any other symptoms.

Although dystrophic epidermolysis bullosa (DEB) is an uncommon cause of skin fragility in neonates, our patient’s presentation was typical because of the extensive blistering and increased fragility of the skin at pressure points. Dystrophic epidermolysis bullosa has both dominant and recessive presentations that span a spectrum from mild and focal skin blistering to extensive blistering with esophageal involvement.¹ Early diagnosis and treatment can mitigate potential failure to thrive or premature death. Inherited mutations in the type VII collagen gene, COL7A1, are causative.² Dominant DEB may be associated with dental caries, swallowing problems secondary to esophageal scarring, and constipation, as well as dystrophic or absent nails. Immunomapping studies of the skin often reveal type VII collagen cytoplasmic granules in the epidermis and weaker reaction in the roof of the subepidermal separation (quiz image).³ Abnormalities in type VII collagen impact the production of anchoring fibrils. Blister cleavage occurs in the sublamina densa with type VII collagen staining evident on the blister roof (quiz image).⁴ Patients with severe generalized recessive DEB may have barely detectable type VII collagen. In our patient, the cytoplasmic staining and weak staining in the epidermal roof of the separation confirmed the clinical impression of dominant DEB.

Autoimmune blistering disease should be considered in the histologic differential diagnosis, but it usually is associated with obvious disease in the mother. Direct immunofluorescence of pemphigoid gestationis reveals linear deposition of C3 at the basement membrane zone, which also can be associated with IgG (Figure 1). Neonates receiving passive transfer of antibodies may develop annular erythema, vesicles, and even dyshidroticlike changes on the soles.⁵

Suction blisters are subepithelial.^6,7 When they occur in the neonatal period, they often are localized and are thought to be the result of vigorous sucking in utero.⁶ They quickly resolve without treatment and do not reveal abnormalities on DIF. If immunomapping is done for type VII collagen, it will be located at the floor of the suction blister (Figure 2).

Bullous pemphigoid is associated with deposition of linear IgG along the dermoepidermal junction—IgG4 is most common—and/or C3 (Figure 3). Direct immunofluorescence on split-skin biopsy reveals IgG on the epidermal side of the blister in bullous pemphigoid in contrast to epidermolysis bullosa acquisita, where the immune deposits are found on the dermal side of the split.^8,9 Linear IgA bullous disease is associated with IgA deposition (Figure 4).^10,11 Secretory IgA derived from breast milk can be causative.¹¹ Neonatal linear IgA bullous disease is a serious condition associated with marked mucosal involvement that can eventuate in respiratory compromise. Prompt recognition is important; breastfeeding must be stopped and supportive therapy must be provided.

Other types of vesicular or pustular eruptions in the newborn usually are easily diagnosed by their typical clinical presentation without biopsy. Erythema toxicum neonatorum usually presents within 1 to 2 days of birth. It is self-limited and often resembles acne, but it also occurs on the trunk and extremities. Transient neonatal pustular melanosis may be present at birth and predominantly is seen in newborns with skin of color. Lesions easily rupture and usually resolve within 1 to 2 days. Infectious causes of blistering often can be identified on clinical examination and confirmed by culture. Herpes simplex virus infection is associated with characteristic multinucleated giant cells as well as steel grey nuclei evident on routine histologic evaluation. Bullous impetigo reveals superficial acantholysis and will have negative findings on DIF.¹²

When a neonate presents with widespread blistering, both genetic disorders of skin fragility as well as passive transfer of antibodies from maternal autoimmune disease need to be considered. Direct immunofluorescence and indirect immunofluorescence immunomapping findings can be useful in clarifying the diagnosis when heritable disorders of skin fragility or autoimmune blistering diseases are a clinical consideration.

The Diagnosis: Dominant Dystrophic Epidermolysis Bullosa

Blisters in a neonate may be caused by infectious, traumatic, autoimmune, or congenital etiologies. Biopsy findings correlated with clinical findings usually can establish a prompt diagnosis when the clinical diagnosis is uncertain. Direct immunofluorescence (DIF) as well as indirect immunofluorescence studies are useful when autoimmune blistering disease or congenital or heritable disorders of skin fragility are in the differential diagnosis. Many genetic abnormalities of skin fragility are associated with marked morbidity and mortality, and prompt diagnosis is essential to provide proper care. Our patient’s parents had no history of skin disorders, and there was no known family history of blistering disease or traumatic birth. A heritable disorder of skin fragility was still a top consideration because of the extensive blistering in the absence of any other symptoms.

Although dystrophic epidermolysis bullosa (DEB) is an uncommon cause of skin fragility in neonates, our patient’s presentation was typical because of the extensive blistering and increased fragility of the skin at pressure points. Dystrophic epidermolysis bullosa has both dominant and recessive presentations that span a spectrum from mild and focal skin blistering to extensive blistering with esophageal involvement.¹ Early diagnosis and treatment can mitigate potential failure to thrive or premature death. Inherited mutations in the type VII collagen gene, COL7A1, are causative.² Dominant DEB may be associated with dental caries, swallowing problems secondary to esophageal scarring, and constipation, as well as dystrophic or absent nails. Immunomapping studies of the skin often reveal type VII collagen cytoplasmic granules in the epidermis and weaker reaction in the roof of the subepidermal separation (quiz image).³ Abnormalities in type VII collagen impact the production of anchoring fibrils. Blister cleavage occurs in the sublamina densa with type VII collagen staining evident on the blister roof (quiz image).⁴ Patients with severe generalized recessive DEB may have barely detectable type VII collagen. In our patient, the cytoplasmic staining and weak staining in the epidermal roof of the separation confirmed the clinical impression of dominant DEB.

Autoimmune blistering disease should be considered in the histologic differential diagnosis, but it usually is associated with obvious disease in the mother. Direct immunofluorescence of pemphigoid gestationis reveals linear deposition of C3 at the basement membrane zone, which also can be associated with IgG (Figure 1). Neonates receiving passive transfer of antibodies may develop annular erythema, vesicles, and even dyshidroticlike changes on the soles.⁵

Suction blisters are subepithelial.^6,7 When they occur in the neonatal period, they often are localized and are thought to be the result of vigorous sucking in utero.⁶ They quickly resolve without treatment and do not reveal abnormalities on DIF. If immunomapping is done for type VII collagen, it will be located at the floor of the suction blister (Figure 2).

Bullous pemphigoid is associated with deposition of linear IgG along the dermoepidermal junction—IgG4 is most common—and/or C3 (Figure 3). Direct immunofluorescence on split-skin biopsy reveals IgG on the epidermal side of the blister in bullous pemphigoid in contrast to epidermolysis bullosa acquisita, where the immune deposits are found on the dermal side of the split.^8,9 Linear IgA bullous disease is associated with IgA deposition (Figure 4).^10,11 Secretory IgA derived from breast milk can be causative.¹¹ Neonatal linear IgA bullous disease is a serious condition associated with marked mucosal involvement that can eventuate in respiratory compromise. Prompt recognition is important; breastfeeding must be stopped and supportive therapy must be provided.

Other types of vesicular or pustular eruptions in the newborn usually are easily diagnosed by their typical clinical presentation without biopsy. Erythema toxicum neonatorum usually presents within 1 to 2 days of birth. It is self-limited and often resembles acne, but it also occurs on the trunk and extremities. Transient neonatal pustular melanosis may be present at birth and predominantly is seen in newborns with skin of color. Lesions easily rupture and usually resolve within 1 to 2 days. Infectious causes of blistering often can be identified on clinical examination and confirmed by culture. Herpes simplex virus infection is associated with characteristic multinucleated giant cells as well as steel grey nuclei evident on routine histologic evaluation. Bullous impetigo reveals superficial acantholysis and will have negative findings on DIF.¹²

When a neonate presents with widespread blistering, both genetic disorders of skin fragility as well as passive transfer of antibodies from maternal autoimmune disease need to be considered. Direct immunofluorescence and indirect immunofluorescence immunomapping findings can be useful in clarifying the diagnosis when heritable disorders of skin fragility or autoimmune blistering diseases are a clinical consideration.

The Diagnosis: Dominant Dystrophic Epidermolysis Bullosa

Blisters in a neonate may be caused by infectious, traumatic, autoimmune, or congenital etiologies. Biopsy findings correlated with clinical findings usually can establish a prompt diagnosis when the clinical diagnosis is uncertain. Direct immunofluorescence (DIF) as well as indirect immunofluorescence studies are useful when autoimmune blistering disease or congenital or heritable disorders of skin fragility are in the differential diagnosis. Many genetic abnormalities of skin fragility are associated with marked morbidity and mortality, and prompt diagnosis is essential to provide proper care. Our patient’s parents had no history of skin disorders, and there was no known family history of blistering disease or traumatic birth. A heritable disorder of skin fragility was still a top consideration because of the extensive blistering in the absence of any other symptoms.

Although dystrophic epidermolysis bullosa (DEB) is an uncommon cause of skin fragility in neonates, our patient’s presentation was typical because of the extensive blistering and increased fragility of the skin at pressure points. Dystrophic epidermolysis bullosa has both dominant and recessive presentations that span a spectrum from mild and focal skin blistering to extensive blistering with esophageal involvement.¹ Early diagnosis and treatment can mitigate potential failure to thrive or premature death. Inherited mutations in the type VII collagen gene, COL7A1, are causative.² Dominant DEB may be associated with dental caries, swallowing problems secondary to esophageal scarring, and constipation, as well as dystrophic or absent nails. Immunomapping studies of the skin often reveal type VII collagen cytoplasmic granules in the epidermis and weaker reaction in the roof of the subepidermal separation (quiz image).³ Abnormalities in type VII collagen impact the production of anchoring fibrils. Blister cleavage occurs in the sublamina densa with type VII collagen staining evident on the blister roof (quiz image).⁴ Patients with severe generalized recessive DEB may have barely detectable type VII collagen. In our patient, the cytoplasmic staining and weak staining in the epidermal roof of the separation confirmed the clinical impression of dominant DEB.

Autoimmune blistering disease should be considered in the histologic differential diagnosis, but it usually is associated with obvious disease in the mother. Direct immunofluorescence of pemphigoid gestationis reveals linear deposition of C3 at the basement membrane zone, which also can be associated with IgG (Figure 1). Neonates receiving passive transfer of antibodies may develop annular erythema, vesicles, and even dyshidroticlike changes on the soles.⁵

Suction blisters are subepithelial.^6,7 When they occur in the neonatal period, they often are localized and are thought to be the result of vigorous sucking in utero.⁶ They quickly resolve without treatment and do not reveal abnormalities on DIF. If immunomapping is done for type VII collagen, it will be located at the floor of the suction blister (Figure 2).

Bullous pemphigoid is associated with deposition of linear IgG along the dermoepidermal junction—IgG4 is most common—and/or C3 (Figure 3). Direct immunofluorescence on split-skin biopsy reveals IgG on the epidermal side of the blister in bullous pemphigoid in contrast to epidermolysis bullosa acquisita, where the immune deposits are found on the dermal side of the split.^8,9 Linear IgA bullous disease is associated with IgA deposition (Figure 4).^10,11 Secretory IgA derived from breast milk can be causative.¹¹ Neonatal linear IgA bullous disease is a serious condition associated with marked mucosal involvement that can eventuate in respiratory compromise. Prompt recognition is important; breastfeeding must be stopped and supportive therapy must be provided.

Other types of vesicular or pustular eruptions in the newborn usually are easily diagnosed by their typical clinical presentation without biopsy. Erythema toxicum neonatorum usually presents within 1 to 2 days of birth. It is self-limited and often resembles acne, but it also occurs on the trunk and extremities. Transient neonatal pustular melanosis may be present at birth and predominantly is seen in newborns with skin of color. Lesions easily rupture and usually resolve within 1 to 2 days. Infectious causes of blistering often can be identified on clinical examination and confirmed by culture. Herpes simplex virus infection is associated with characteristic multinucleated giant cells as well as steel grey nuclei evident on routine histologic evaluation. Bullous impetigo reveals superficial acantholysis and will have negative findings on DIF.¹²

When a neonate presents with widespread blistering, both genetic disorders of skin fragility as well as passive transfer of antibodies from maternal autoimmune disease need to be considered. Direct immunofluorescence and indirect immunofluorescence immunomapping findings can be useful in clarifying the diagnosis when heritable disorders of skin fragility or autoimmune blistering diseases are a clinical consideration.

Practice Gap

Nail art can skew the results of optical coherence tomography (OCT), a noninvasive imaging technology that is used to visualize nail morphology in diseases such as psoriatic arthritis and onychomycosis, with a penetration depth of 2 mm and high-resolution images.¹ Few studies have evaluated the effects of nail art on OCT. Saleah and colleagues¹ found that clear, semitransparent, and red nail polishes do not interfere with visualization of the nail plate, whereas nontransparent gel polish and art stones obscure the image. They did not comment on the effect of glitter nail art in their study, though they did test 1 nail that contained glitter.¹ Monpeurt et al² compared matte and glossy nail polishes. They found that matte polish was readily identifiable from the nail plate, whereas glossy polish presented a greater number of artifacts.²

The Solution

We looked at 3 glitter nail polishes—gold, pink, and silver—that were scanned by OCT to assess the effect of the polish on the resulting image. We determined that glitter particles completely obscured the nail bed and nail plate, regardless of color (Figure 1). Glossy clear polish imparted a distinct film on the top of the nail plate that did not obscure the nail plate or the nail bed (Figure 2).

We conclude that glitter nail polish contains numerous reflective solid particles that interfere with OCT imaging of the nail plate and nail bed. As a result, we recommend removal of nail art to properly assess nail pathology. Because removal may need to be conducted by a nail technician, the treating clinician should inform the patient ahead of time to come to the appointment with bare (ie, unpolished) nails.

Practice Implications

Bringing awareness to the necessity of removing nail art prior to OCT imaging is crucial because many patients partake in its application, and removal may require the involvement of a professional nail technician. If a patient can be made aware that they should remove all nail art in advance, they will be better prepared for an OCT imaging session. Such a protocol increases efficiency, decreases diagnostic delay, and reduces cost associated with multiple office visits.

Practice Gap

Nail art can skew the results of optical coherence tomography (OCT), a noninvasive imaging technology that is used to visualize nail morphology in diseases such as psoriatic arthritis and onychomycosis, with a penetration depth of 2 mm and high-resolution images.¹ Few studies have evaluated the effects of nail art on OCT. Saleah and colleagues¹ found that clear, semitransparent, and red nail polishes do not interfere with visualization of the nail plate, whereas nontransparent gel polish and art stones obscure the image. They did not comment on the effect of glitter nail art in their study, though they did test 1 nail that contained glitter.¹ Monpeurt et al² compared matte and glossy nail polishes. They found that matte polish was readily identifiable from the nail plate, whereas glossy polish presented a greater number of artifacts.²

The Solution

We looked at 3 glitter nail polishes—gold, pink, and silver—that were scanned by OCT to assess the effect of the polish on the resulting image. We determined that glitter particles completely obscured the nail bed and nail plate, regardless of color (Figure 1). Glossy clear polish imparted a distinct film on the top of the nail plate that did not obscure the nail plate or the nail bed (Figure 2).

We conclude that glitter nail polish contains numerous reflective solid particles that interfere with OCT imaging of the nail plate and nail bed. As a result, we recommend removal of nail art to properly assess nail pathology. Because removal may need to be conducted by a nail technician, the treating clinician should inform the patient ahead of time to come to the appointment with bare (ie, unpolished) nails.

Practice Implications

Bringing awareness to the necessity of removing nail art prior to OCT imaging is crucial because many patients partake in its application, and removal may require the involvement of a professional nail technician. If a patient can be made aware that they should remove all nail art in advance, they will be better prepared for an OCT imaging session. Such a protocol increases efficiency, decreases diagnostic delay, and reduces cost associated with multiple office visits.

Practice Gap

Nail art can skew the results of optical coherence tomography (OCT), a noninvasive imaging technology that is used to visualize nail morphology in diseases such as psoriatic arthritis and onychomycosis, with a penetration depth of 2 mm and high-resolution images.¹ Few studies have evaluated the effects of nail art on OCT. Saleah and colleagues¹ found that clear, semitransparent, and red nail polishes do not interfere with visualization of the nail plate, whereas nontransparent gel polish and art stones obscure the image. They did not comment on the effect of glitter nail art in their study, though they did test 1 nail that contained glitter.¹ Monpeurt et al² compared matte and glossy nail polishes. They found that matte polish was readily identifiable from the nail plate, whereas glossy polish presented a greater number of artifacts.²

The Solution

We looked at 3 glitter nail polishes—gold, pink, and silver—that were scanned by OCT to assess the effect of the polish on the resulting image. We determined that glitter particles completely obscured the nail bed and nail plate, regardless of color (Figure 1). Glossy clear polish imparted a distinct film on the top of the nail plate that did not obscure the nail plate or the nail bed (Figure 2).

We conclude that glitter nail polish contains numerous reflective solid particles that interfere with OCT imaging of the nail plate and nail bed. As a result, we recommend removal of nail art to properly assess nail pathology. Because removal may need to be conducted by a nail technician, the treating clinician should inform the patient ahead of time to come to the appointment with bare (ie, unpolished) nails.

Practice Implications

Bringing awareness to the necessity of removing nail art prior to OCT imaging is crucial because many patients partake in its application, and removal may require the involvement of a professional nail technician. If a patient can be made aware that they should remove all nail art in advance, they will be better prepared for an OCT imaging session. Such a protocol increases efficiency, decreases diagnostic delay, and reduces cost associated with multiple office visits.

The Diagnosis: Poroma

Histopathology showed an endophytic expansion of the epidermis by bland, uniform, basaloid epithelial cells with focal ductal differentiation and an abrupt transition with surrounding epidermal keratinocytes (Figure), consistent with a diagnosis of poroma. The patient elected to monitor the lesion rather than to have it excised.

Eccrine poroma, used interchangeably with the term poroma, is a rare benign adnexal tumor of the eccrine sweat glands resulting from proliferation of the acrosyringium.^1,2 It often occurs on the palms or soles, though it also can arise anywhere sweat glands are present.¹ Eccrine poromas often appear in middle-aged individuals as singular, well-circumscribed, red-brown papules or nodules.³ A characteristic feature is a shallow, cup-shaped depression within the larger papule or nodule.¹

Because the condition is benign and often asymptomatic, it can be safely monitored for progression.¹ However, if the lesion is symptomatic or located in a sensitive area, complete excision is curative.⁴ Eccrine poromas can recur, making close monitoring following excision important.⁵ The development of bleeding, itching, or pain in a previously asymptomatic lesion may indicate possible malignant transformation, which occurs in only 18% of cases.⁶

The differential diagnosis includes basal cell carcinoma, circumscribed acral hypokeratosis, Kaposi sarcoma, and pyogenic granuloma. Basal cell carcinoma is the most common type of skin cancer.⁷ In rare cases it has been shown to present on the palms or soles as a slowgrowing, reddish-pink papule or plaque with central ulceration. It typically is asymptomatic. Histopathology shows dermal nests of basaloid cells with peripheral palisading, stromal mucin, and peritumoral clefts. Treatment is surgical excision.⁷

Circumscribed acral hypokeratosis presents on the palms or soles as a solitary, shallow, well-defined lesion with a flat base and raised border.⁸ It often is red-pink in color and most frequently occurs in middle-aged women. Although the cause of the condition is unknown, it is thought to be the result of trauma or human papillomavirus infection.8 Biopsy results characteristically show hypokeratosis demarcated by a sharp and frayed cutoff from uninvolved acral skin with discrete hypogranulosis, dilated blood vessels in the papillary dermis, and slightly thickened collagen fibers in the reticular dermis.⁹ Surgical excision is a potential treatment option, as topical corticosteroids, retinoids, and calcipotriene have not been shown to be effective; spontaneous resolution has been reported.⁸

Kaposi sarcoma is a vascular neoplasm that is associated with human herpesvirus 8 infection.¹⁰ It typically presents on mucocutaneous sites and the lower extremities. Palmar involvement has been reported in rare cases, occurring as a solitary, well-demarcated, violaceous macule or patch that may be painful.^10-12 Characteristic histopathologic features include a proliferation in the dermis of slitlike vascular spaces and spindle cell proliferation.¹³ Treatment options include cryosurgery; pulsed dye laser; and topical, intralesional, or systemic chemotherapy agents, depending on the stage of the patient’s disease. Antiretroviral therapy is indicated for patients with Kaposi sarcoma secondary to AIDS.¹⁴

Pyogenic granuloma presents as a solitary red-brown or bluish-black papule or nodule that bleeds easily when manipulated.¹⁵ It commonly occurs following trauma, typically on the fingers, feet, and lips.⁶ Although benign, potential complications include ulceration and blood loss. Pyogenic granulomas can be treated via curettage and cautery, excision, cryosurgery, or pulsed dye laser.¹⁵

The Diagnosis: Poroma

Histopathology showed an endophytic expansion of the epidermis by bland, uniform, basaloid epithelial cells with focal ductal differentiation and an abrupt transition with surrounding epidermal keratinocytes (Figure), consistent with a diagnosis of poroma. The patient elected to monitor the lesion rather than to have it excised.

Eccrine poroma, used interchangeably with the term poroma, is a rare benign adnexal tumor of the eccrine sweat glands resulting from proliferation of the acrosyringium.^1,2 It often occurs on the palms or soles, though it also can arise anywhere sweat glands are present.¹ Eccrine poromas often appear in middle-aged individuals as singular, well-circumscribed, red-brown papules or nodules.³ A characteristic feature is a shallow, cup-shaped depression within the larger papule or nodule.¹

Because the condition is benign and often asymptomatic, it can be safely monitored for progression.¹ However, if the lesion is symptomatic or located in a sensitive area, complete excision is curative.⁴ Eccrine poromas can recur, making close monitoring following excision important.⁵ The development of bleeding, itching, or pain in a previously asymptomatic lesion may indicate possible malignant transformation, which occurs in only 18% of cases.⁶

The differential diagnosis includes basal cell carcinoma, circumscribed acral hypokeratosis, Kaposi sarcoma, and pyogenic granuloma. Basal cell carcinoma is the most common type of skin cancer.⁷ In rare cases it has been shown to present on the palms or soles as a slowgrowing, reddish-pink papule or plaque with central ulceration. It typically is asymptomatic. Histopathology shows dermal nests of basaloid cells with peripheral palisading, stromal mucin, and peritumoral clefts. Treatment is surgical excision.⁷

Circumscribed acral hypokeratosis presents on the palms or soles as a solitary, shallow, well-defined lesion with a flat base and raised border.⁸ It often is red-pink in color and most frequently occurs in middle-aged women. Although the cause of the condition is unknown, it is thought to be the result of trauma or human papillomavirus infection.8 Biopsy results characteristically show hypokeratosis demarcated by a sharp and frayed cutoff from uninvolved acral skin with discrete hypogranulosis, dilated blood vessels in the papillary dermis, and slightly thickened collagen fibers in the reticular dermis.⁹ Surgical excision is a potential treatment option, as topical corticosteroids, retinoids, and calcipotriene have not been shown to be effective; spontaneous resolution has been reported.⁸

Kaposi sarcoma is a vascular neoplasm that is associated with human herpesvirus 8 infection.¹⁰ It typically presents on mucocutaneous sites and the lower extremities. Palmar involvement has been reported in rare cases, occurring as a solitary, well-demarcated, violaceous macule or patch that may be painful.^10-12 Characteristic histopathologic features include a proliferation in the dermis of slitlike vascular spaces and spindle cell proliferation.¹³ Treatment options include cryosurgery; pulsed dye laser; and topical, intralesional, or systemic chemotherapy agents, depending on the stage of the patient’s disease. Antiretroviral therapy is indicated for patients with Kaposi sarcoma secondary to AIDS.¹⁴

Pyogenic granuloma presents as a solitary red-brown or bluish-black papule or nodule that bleeds easily when manipulated.¹⁵ It commonly occurs following trauma, typically on the fingers, feet, and lips.⁶ Although benign, potential complications include ulceration and blood loss. Pyogenic granulomas can be treated via curettage and cautery, excision, cryosurgery, or pulsed dye laser.¹⁵

The Diagnosis: Poroma

Histopathology showed an endophytic expansion of the epidermis by bland, uniform, basaloid epithelial cells with focal ductal differentiation and an abrupt transition with surrounding epidermal keratinocytes (Figure), consistent with a diagnosis of poroma. The patient elected to monitor the lesion rather than to have it excised.

Eccrine poroma, used interchangeably with the term poroma, is a rare benign adnexal tumor of the eccrine sweat glands resulting from proliferation of the acrosyringium.^1,2 It often occurs on the palms or soles, though it also can arise anywhere sweat glands are present.¹ Eccrine poromas often appear in middle-aged individuals as singular, well-circumscribed, red-brown papules or nodules.³ A characteristic feature is a shallow, cup-shaped depression within the larger papule or nodule.¹

Because the condition is benign and often asymptomatic, it can be safely monitored for progression.¹ However, if the lesion is symptomatic or located in a sensitive area, complete excision is curative.⁴ Eccrine poromas can recur, making close monitoring following excision important.⁵ The development of bleeding, itching, or pain in a previously asymptomatic lesion may indicate possible malignant transformation, which occurs in only 18% of cases.⁶

The differential diagnosis includes basal cell carcinoma, circumscribed acral hypokeratosis, Kaposi sarcoma, and pyogenic granuloma. Basal cell carcinoma is the most common type of skin cancer.⁷ In rare cases it has been shown to present on the palms or soles as a slowgrowing, reddish-pink papule or plaque with central ulceration. It typically is asymptomatic. Histopathology shows dermal nests of basaloid cells with peripheral palisading, stromal mucin, and peritumoral clefts. Treatment is surgical excision.⁷

Circumscribed acral hypokeratosis presents on the palms or soles as a solitary, shallow, well-defined lesion with a flat base and raised border.⁸ It often is red-pink in color and most frequently occurs in middle-aged women. Although the cause of the condition is unknown, it is thought to be the result of trauma or human papillomavirus infection.8 Biopsy results characteristically show hypokeratosis demarcated by a sharp and frayed cutoff from uninvolved acral skin with discrete hypogranulosis, dilated blood vessels in the papillary dermis, and slightly thickened collagen fibers in the reticular dermis.⁹ Surgical excision is a potential treatment option, as topical corticosteroids, retinoids, and calcipotriene have not been shown to be effective; spontaneous resolution has been reported.⁸

Kaposi sarcoma is a vascular neoplasm that is associated with human herpesvirus 8 infection.¹⁰ It typically presents on mucocutaneous sites and the lower extremities. Palmar involvement has been reported in rare cases, occurring as a solitary, well-demarcated, violaceous macule or patch that may be painful.^10-12 Characteristic histopathologic features include a proliferation in the dermis of slitlike vascular spaces and spindle cell proliferation.¹³ Treatment options include cryosurgery; pulsed dye laser; and topical, intralesional, or systemic chemotherapy agents, depending on the stage of the patient’s disease. Antiretroviral therapy is indicated for patients with Kaposi sarcoma secondary to AIDS.¹⁴

Pyogenic granuloma presents as a solitary red-brown or bluish-black papule or nodule that bleeds easily when manipulated.¹⁵ It commonly occurs following trauma, typically on the fingers, feet, and lips.⁶ Although benign, potential complications include ulceration and blood loss. Pyogenic granulomas can be treated via curettage and cautery, excision, cryosurgery, or pulsed dye laser.¹⁵

Scabies is caused by cutaneous ectoparasitic infection by the mite Sarcoptes scabiei var hominis. The infection is highly contagious via direct skin-to-skin contact or indirectly through infested bedding, clothing or fomites.^1,2 Scabies occurs at all ages, in all ethnic groups, and at all socioeconomic levels.¹ Analysis by the Global Burden of Disease estimates that 200 million individuals have been infected with scabies worldwide. The World Health Organization has declared scabies a neglected tropical disease.³

Crusted scabies is a severe and rare form of scabies, with hyperinfestation of thousands to millions of mites, and more commonly is associated with immunosuppressed states, including HIV and hematologic malignancies.^1,2,4 Crusted scabies has a high mortality rate due to sepsis when left untreated.^3,5

Occasionally, iatrogenic immunosuppression contributes to the development of crusted scabies.^1,2 Iatrogenic immunosuppression leading to crusted scabies most commonly occurs secondary to immunosuppression after bone marrow or solid organ transplantation.⁶ Less often, crusted scabies is caused by iatrogenic immunosuppression from other clinical scenarios.^1,2

We describe a patient with iatrogenic immunosuppression due to azathioprine-induced myelosuppression for the treatment of granulomatosis with polyangiitis (GPA) who developed crusted scabies that clinically presented as erythroderma. Crusted scabies should be included in the differential diagnosis of erythroderma, especially in the setting of iatrogenic immunosuppression, for timely and appropriate management.

Case Report

An 84-year-old man presented with worsening pruritus, erythema, and thick yellow scale that progressed to erythroderma over the last 2 weeks. He was diagnosed with GPA 6 months prior to presentation and was treated with azathioprine 150 mg/d, prednisone 10 mg/d, and sulfamethoxazole 800 mg plus trimethoprim 160 mg twice weekly for prophylaxis against Pneumocystis jirovecii pneumonia.

Three weeks prior to presentation, the patient was hospitalized for pancytopenia attributed to azathioprine-induced myelosuppression (hemoglobin, 6.1 g/dL [reference range, 13.5–18.0 g/dL]; hematocrit, 17.5% [reference range, 42%–52%]; white blood cell count, 1.66×10³/μL [reference range, 4.0–10.5×10³/μL]; platelet count, 146×10³/μL [reference range, 150–450×10³/μL]; absolute neutrophil count, 1.29×10³/μL [reference range, 1.4–6.5×10³/μL]). He was transferred to a skilled nursing facility after discharge and referred to dermatology for evaluation of the worsening pruritic rash.

At the current presentation, the patient denied close contact with anyone who had a similar rash at home or at the skilled nursing facility. Physical examination revealed diffuse erythroderma with yellow scale on the scalp, trunk, arms, and legs (Figure 1). The palms showed scattered 2- to 3-mm pustules. The mucosal surfaces did not have lesions. A punch biopsy of a pustule from the right arm revealed focal spongiosis, parakeratosis, and acanthosis, as well as a perivascular and interstitial mixed inflammatory infiltrate with lymphocytes and eosinophils. Organisms morphologically compatible with scabies were found in the stratum corneum (Figure 2). Another punch biopsy of a pustule from the right arm was performed for direct immunofluorescence (DIF) and was negative for immunoglobulin deposition. Mineral oil preparation from pustules on the palm was positive for mites.

The patient was treated with permethrin cream 5% and oral ivermectin 200 μg/kg on day 1 and day 10. The prednisone dosage was increased from 10 mg/d to 50 mg/d and tapered over 2 weeks to treat the symptomatic rash and GPA. He remains on maintenance rituximab for GPA, without recurrence of scabies.

Comment

Pathogenesis—As an obligate parasite, S scabiei spends its entire life cycle within the host. Impregnated female mites burrow into the epidermis after mating and lay eggs daily for 1 to 2 months. Eggs hatch 2 or 3 days later. Larvae then migrate to the skin surface; burrow into the stratum corneum, where they mature into adults; and then mate on the skin surface.^1,4

Clinical Presentation and Sequelae—Typically, scabies presents 2 to 6 weeks after initial exposure with generalized and intense itching and inflammatory pruritic papules on the finger webs, wrists, elbows, axillae, buttocks, umbilicus, genitalia, and areolae.¹ Burrows are specific for scabies but may not always be present. Often, there are nonspecific secondary lesions, including excoriations, dermatitis, and impetiginization.

Complications of scabies can be severe, with initial colonization and infection of the skin resulting in impetigo and cellulitis. Systematic sequelae from local skin infection include post-streptococcal glomerulonephritis, rheumatic fever, and sepsis. Mortality from sepsis in scabies can be high.^3,5

Classic Crusted Scabies and Other Variants—Crusted scabies presents with psoriasiform hyperkeratotic plaques involving the hands and feet with potential nail involvement that can become more generalized.¹ Alterations in CD4⁺ T-cell function have been implicated in the development of crusted scabies, in which an excessive helper T cell (T_H2) response is elicited against the ectoparasite, which may help explain the intense pruritus of scabies.⁶ Occasionally, iatrogenic immunosuppression contributes to development of crusted scabies,¹ as was the case with our patient. However, it is rare for crusted scabies to present with erythroderma.⁷

Other atypical presentations of scabies include a seborrheic dermatitis–like presentation in infants, nodular lesions in the groin and axillae in more chronic scabies, and vesicles or bullous lesions.¹

Diagnosis—Identification of mites, eggs, or feces is necessary for definitive diagnosis of scabies.⁸ These materials can be obtained through skin scrapings with mineral oil and observed under light microscopy or direct dermoscopy. Multiple scrapings on many lesions should be performed because failure to identify mites can be common and does not rule out scabies. Dermoscopic examination of active lesions under low power also can be helpful, given that identification of dark brown triangular structures can correspond to visualization of the pigmented anterior section of the mite.^9-11 A skin biopsy can help identify mites, but histopathology often shows a nonspecific hypersensitivity reaction.¹² Therefore, empiric treatment often is necessary.

Differential Diagnosis—The differential diagnosis of erythroderma is broad and includes a drug eruption; Sézary syndrome; and pre-existing skin diseases, including psoriasis, atopic dermatitis, pityriasis rubra pilaris, pemphigus foliaceus, and bullous pemphigoid. Histopathology is critical to differentiate these diagnoses. Bullous pemphigoid and pemphigus foliaceus are immunobullous diseases that typically are positive for immunoglobulin deposition on DIF. In rare cases, scabies also can present with bullae and positive DIF test results.¹³

Treatment—First-line treatment of crusted scabies in the United States is permethrin cream 5%, followed by oral ivermectin 200 μg/kg.^4,5,14,15 Other scabicides include topicals such as benzyl benzoate 10% to 25%; precipitated sulfur 2% to 10%; crotamiton 10%; malathion 0.5%; and lindane 1%.⁵ The association of neurotoxicity with lindane has considerably reduced the drug’s use.¹

During treatment of scabies, it is important to isolate patients to mitigate the possibility of spread.⁴ Pruritus can persist for a few weeks after completion of therapy.⁵ Patients should be closely monitored to ensure that this symptom is secondary to skin inflammation and not incomplete treatment.

Treatment of crusted scabies may require repeated treatments to decrease the notable mite burden as well as the associated crusting and scale. Adding a keratolytic such as 5% to 10% salicylic acid in petrolatum to the treatment regimen may be useful for breaking up thick scale.⁵

Immunosuppression—With numerous immunomodulatory drugs for treating autoimmunity comes an increased risk for iatrogenic immunosuppression that may contribute to the development of crusted scabies.¹⁶ In a number of autoimmune diseases such as rheumatoid arthritis,^17-19 psoriasis,^20,21 pemphigus vulgaris,²² systemic lupus erythematosus,²³ systemic sclerosis,^22,24 bullous pemphigoid,^25,26 and dermatomyositis,²⁷ patients have developed crusted scabies secondary to treatment-related immunosuppression. These immunosuppressive therapies include systemic steroids,^22-24,26-31 methotrexate,²³ infliximab,¹⁸ adalimumab,²¹ toclizumab,¹⁹ and etanercept.²⁰ In a case of drug-induced Stevens-Johnson syndrome, the patient developed crusted scabies during long-term use of oral steroids.²²

Patients with a malignancy who are being treated with chemotherapy also can develop crusted scabies.²⁸ Crusted scabies has even been associated with long-term topical steroid^32-34 and topical calcineurin inhibitor use.¹⁶

Iatrogenic immunosuppression in our patient resulted from treatment of GPA with azathioprine, an immunosuppressive drug that acts as an antagonist of the breakdown of purines, leading to inhibition of DNA, RNA, and protein synthesis.³⁵ On occasion, azathioprine can induce immunosuppression in the form of myelosuppression and resulting pancytopenia, as was the case with our patient.

Conclusion

Although scabies is designated as a neglected tropical disease by the World Health Organization, it still causes a notable burden worldwide, regardless of the economics. Our case highlights an unusual presentation of scabies as erythroderma in the setting of iatrogenic immunosuppression from azathioprine use. Dermatologists should consider crusted scabies in the differential diagnosis of erythroderma, especially in immunocompromised patients, to avoid delays in diagnosis and treatment. Immunosuppressive therapy is an important mainstay in the treatment of many conditions, but it is important to consider that these medications can place patients at an increased risk for rare opportunistic infections. Therefore, patients receiving such treatment should be closely monitored.

Scabies is caused by cutaneous ectoparasitic infection by the mite Sarcoptes scabiei var hominis. The infection is highly contagious via direct skin-to-skin contact or indirectly through infested bedding, clothing or fomites.^1,2 Scabies occurs at all ages, in all ethnic groups, and at all socioeconomic levels.¹ Analysis by the Global Burden of Disease estimates that 200 million individuals have been infected with scabies worldwide. The World Health Organization has declared scabies a neglected tropical disease.³

Crusted scabies is a severe and rare form of scabies, with hyperinfestation of thousands to millions of mites, and more commonly is associated with immunosuppressed states, including HIV and hematologic malignancies.^1,2,4 Crusted scabies has a high mortality rate due to sepsis when left untreated.^3,5

Occasionally, iatrogenic immunosuppression contributes to the development of crusted scabies.^1,2 Iatrogenic immunosuppression leading to crusted scabies most commonly occurs secondary to immunosuppression after bone marrow or solid organ transplantation.⁶ Less often, crusted scabies is caused by iatrogenic immunosuppression from other clinical scenarios.^1,2

We describe a patient with iatrogenic immunosuppression due to azathioprine-induced myelosuppression for the treatment of granulomatosis with polyangiitis (GPA) who developed crusted scabies that clinically presented as erythroderma. Crusted scabies should be included in the differential diagnosis of erythroderma, especially in the setting of iatrogenic immunosuppression, for timely and appropriate management.

Case Report

An 84-year-old man presented with worsening pruritus, erythema, and thick yellow scale that progressed to erythroderma over the last 2 weeks. He was diagnosed with GPA 6 months prior to presentation and was treated with azathioprine 150 mg/d, prednisone 10 mg/d, and sulfamethoxazole 800 mg plus trimethoprim 160 mg twice weekly for prophylaxis against Pneumocystis jirovecii pneumonia.

Three weeks prior to presentation, the patient was hospitalized for pancytopenia attributed to azathioprine-induced myelosuppression (hemoglobin, 6.1 g/dL [reference range, 13.5–18.0 g/dL]; hematocrit, 17.5% [reference range, 42%–52%]; white blood cell count, 1.66×10³/μL [reference range, 4.0–10.5×10³/μL]; platelet count, 146×10³/μL [reference range, 150–450×10³/μL]; absolute neutrophil count, 1.29×10³/μL [reference range, 1.4–6.5×10³/μL]). He was transferred to a skilled nursing facility after discharge and referred to dermatology for evaluation of the worsening pruritic rash.

At the current presentation, the patient denied close contact with anyone who had a similar rash at home or at the skilled nursing facility. Physical examination revealed diffuse erythroderma with yellow scale on the scalp, trunk, arms, and legs (Figure 1). The palms showed scattered 2- to 3-mm pustules. The mucosal surfaces did not have lesions. A punch biopsy of a pustule from the right arm revealed focal spongiosis, parakeratosis, and acanthosis, as well as a perivascular and interstitial mixed inflammatory infiltrate with lymphocytes and eosinophils. Organisms morphologically compatible with scabies were found in the stratum corneum (Figure 2). Another punch biopsy of a pustule from the right arm was performed for direct immunofluorescence (DIF) and was negative for immunoglobulin deposition. Mineral oil preparation from pustules on the palm was positive for mites.

The patient was treated with permethrin cream 5% and oral ivermectin 200 μg/kg on day 1 and day 10. The prednisone dosage was increased from 10 mg/d to 50 mg/d and tapered over 2 weeks to treat the symptomatic rash and GPA. He remains on maintenance rituximab for GPA, without recurrence of scabies.

Comment

Pathogenesis—As an obligate parasite, S scabiei spends its entire life cycle within the host. Impregnated female mites burrow into the epidermis after mating and lay eggs daily for 1 to 2 months. Eggs hatch 2 or 3 days later. Larvae then migrate to the skin surface; burrow into the stratum corneum, where they mature into adults; and then mate on the skin surface.^1,4

Clinical Presentation and Sequelae—Typically, scabies presents 2 to 6 weeks after initial exposure with generalized and intense itching and inflammatory pruritic papules on the finger webs, wrists, elbows, axillae, buttocks, umbilicus, genitalia, and areolae.¹ Burrows are specific for scabies but may not always be present. Often, there are nonspecific secondary lesions, including excoriations, dermatitis, and impetiginization.

Complications of scabies can be severe, with initial colonization and infection of the skin resulting in impetigo and cellulitis. Systematic sequelae from local skin infection include post-streptococcal glomerulonephritis, rheumatic fever, and sepsis. Mortality from sepsis in scabies can be high.^3,5

Classic Crusted Scabies and Other Variants—Crusted scabies presents with psoriasiform hyperkeratotic plaques involving the hands and feet with potential nail involvement that can become more generalized.¹ Alterations in CD4⁺ T-cell function have been implicated in the development of crusted scabies, in which an excessive helper T cell (T_H2) response is elicited against the ectoparasite, which may help explain the intense pruritus of scabies.⁶ Occasionally, iatrogenic immunosuppression contributes to development of crusted scabies,¹ as was the case with our patient. However, it is rare for crusted scabies to present with erythroderma.⁷

Other atypical presentations of scabies include a seborrheic dermatitis–like presentation in infants, nodular lesions in the groin and axillae in more chronic scabies, and vesicles or bullous lesions.¹

Diagnosis—Identification of mites, eggs, or feces is necessary for definitive diagnosis of scabies.⁸ These materials can be obtained through skin scrapings with mineral oil and observed under light microscopy or direct dermoscopy. Multiple scrapings on many lesions should be performed because failure to identify mites can be common and does not rule out scabies. Dermoscopic examination of active lesions under low power also can be helpful, given that identification of dark brown triangular structures can correspond to visualization of the pigmented anterior section of the mite.^9-11 A skin biopsy can help identify mites, but histopathology often shows a nonspecific hypersensitivity reaction.¹² Therefore, empiric treatment often is necessary.

Differential Diagnosis—The differential diagnosis of erythroderma is broad and includes a drug eruption; Sézary syndrome; and pre-existing skin diseases, including psoriasis, atopic dermatitis, pityriasis rubra pilaris, pemphigus foliaceus, and bullous pemphigoid. Histopathology is critical to differentiate these diagnoses. Bullous pemphigoid and pemphigus foliaceus are immunobullous diseases that typically are positive for immunoglobulin deposition on DIF. In rare cases, scabies also can present with bullae and positive DIF test results.¹³

Treatment—First-line treatment of crusted scabies in the United States is permethrin cream 5%, followed by oral ivermectin 200 μg/kg.^4,5,14,15 Other scabicides include topicals such as benzyl benzoate 10% to 25%; precipitated sulfur 2% to 10%; crotamiton 10%; malathion 0.5%; and lindane 1%.⁵ The association of neurotoxicity with lindane has considerably reduced the drug’s use.¹

During treatment of scabies, it is important to isolate patients to mitigate the possibility of spread.⁴ Pruritus can persist for a few weeks after completion of therapy.⁵ Patients should be closely monitored to ensure that this symptom is secondary to skin inflammation and not incomplete treatment.

Treatment of crusted scabies may require repeated treatments to decrease the notable mite burden as well as the associated crusting and scale. Adding a keratolytic such as 5% to 10% salicylic acid in petrolatum to the treatment regimen may be useful for breaking up thick scale.⁵

Immunosuppression—With numerous immunomodulatory drugs for treating autoimmunity comes an increased risk for iatrogenic immunosuppression that may contribute to the development of crusted scabies.¹⁶ In a number of autoimmune diseases such as rheumatoid arthritis,^17-19 psoriasis,^20,21 pemphigus vulgaris,²² systemic lupus erythematosus,²³ systemic sclerosis,^22,24 bullous pemphigoid,^25,26 and dermatomyositis,²⁷ patients have developed crusted scabies secondary to treatment-related immunosuppression. These immunosuppressive therapies include systemic steroids,^22-24,26-31 methotrexate,²³ infliximab,¹⁸ adalimumab,²¹ toclizumab,¹⁹ and etanercept.²⁰ In a case of drug-induced Stevens-Johnson syndrome, the patient developed crusted scabies during long-term use of oral steroids.²²

Patients with a malignancy who are being treated with chemotherapy also can develop crusted scabies.²⁸ Crusted scabies has even been associated with long-term topical steroid^32-34 and topical calcineurin inhibitor use.¹⁶

Iatrogenic immunosuppression in our patient resulted from treatment of GPA with azathioprine, an immunosuppressive drug that acts as an antagonist of the breakdown of purines, leading to inhibition of DNA, RNA, and protein synthesis.³⁵ On occasion, azathioprine can induce immunosuppression in the form of myelosuppression and resulting pancytopenia, as was the case with our patient.

Conclusion

Although scabies is designated as a neglected tropical disease by the World Health Organization, it still causes a notable burden worldwide, regardless of the economics. Our case highlights an unusual presentation of scabies as erythroderma in the setting of iatrogenic immunosuppression from azathioprine use. Dermatologists should consider crusted scabies in the differential diagnosis of erythroderma, especially in immunocompromised patients, to avoid delays in diagnosis and treatment. Immunosuppressive therapy is an important mainstay in the treatment of many conditions, but it is important to consider that these medications can place patients at an increased risk for rare opportunistic infections. Therefore, patients receiving such treatment should be closely monitored.

Scabies is caused by cutaneous ectoparasitic infection by the mite Sarcoptes scabiei var hominis. The infection is highly contagious via direct skin-to-skin contact or indirectly through infested bedding, clothing or fomites.^1,2 Scabies occurs at all ages, in all ethnic groups, and at all socioeconomic levels.¹ Analysis by the Global Burden of Disease estimates that 200 million individuals have been infected with scabies worldwide. The World Health Organization has declared scabies a neglected tropical disease.³

Crusted scabies is a severe and rare form of scabies, with hyperinfestation of thousands to millions of mites, and more commonly is associated with immunosuppressed states, including HIV and hematologic malignancies.^1,2,4 Crusted scabies has a high mortality rate due to sepsis when left untreated.^3,5

Occasionally, iatrogenic immunosuppression contributes to the development of crusted scabies.^1,2 Iatrogenic immunosuppression leading to crusted scabies most commonly occurs secondary to immunosuppression after bone marrow or solid organ transplantation.⁶ Less often, crusted scabies is caused by iatrogenic immunosuppression from other clinical scenarios.^1,2

We describe a patient with iatrogenic immunosuppression due to azathioprine-induced myelosuppression for the treatment of granulomatosis with polyangiitis (GPA) who developed crusted scabies that clinically presented as erythroderma. Crusted scabies should be included in the differential diagnosis of erythroderma, especially in the setting of iatrogenic immunosuppression, for timely and appropriate management.

Case Report

An 84-year-old man presented with worsening pruritus, erythema, and thick yellow scale that progressed to erythroderma over the last 2 weeks. He was diagnosed with GPA 6 months prior to presentation and was treated with azathioprine 150 mg/d, prednisone 10 mg/d, and sulfamethoxazole 800 mg plus trimethoprim 160 mg twice weekly for prophylaxis against Pneumocystis jirovecii pneumonia.

Three weeks prior to presentation, the patient was hospitalized for pancytopenia attributed to azathioprine-induced myelosuppression (hemoglobin, 6.1 g/dL [reference range, 13.5–18.0 g/dL]; hematocrit, 17.5% [reference range, 42%–52%]; white blood cell count, 1.66×10³/μL [reference range, 4.0–10.5×10³/μL]; platelet count, 146×10³/μL [reference range, 150–450×10³/μL]; absolute neutrophil count, 1.29×10³/μL [reference range, 1.4–6.5×10³/μL]). He was transferred to a skilled nursing facility after discharge and referred to dermatology for evaluation of the worsening pruritic rash.

At the current presentation, the patient denied close contact with anyone who had a similar rash at home or at the skilled nursing facility. Physical examination revealed diffuse erythroderma with yellow scale on the scalp, trunk, arms, and legs (Figure 1). The palms showed scattered 2- to 3-mm pustules. The mucosal surfaces did not have lesions. A punch biopsy of a pustule from the right arm revealed focal spongiosis, parakeratosis, and acanthosis, as well as a perivascular and interstitial mixed inflammatory infiltrate with lymphocytes and eosinophils. Organisms morphologically compatible with scabies were found in the stratum corneum (Figure 2). Another punch biopsy of a pustule from the right arm was performed for direct immunofluorescence (DIF) and was negative for immunoglobulin deposition. Mineral oil preparation from pustules on the palm was positive for mites.

The patient was treated with permethrin cream 5% and oral ivermectin 200 μg/kg on day 1 and day 10. The prednisone dosage was increased from 10 mg/d to 50 mg/d and tapered over 2 weeks to treat the symptomatic rash and GPA. He remains on maintenance rituximab for GPA, without recurrence of scabies.

Comment

Pathogenesis—As an obligate parasite, S scabiei spends its entire life cycle within the host. Impregnated female mites burrow into the epidermis after mating and lay eggs daily for 1 to 2 months. Eggs hatch 2 or 3 days later. Larvae then migrate to the skin surface; burrow into the stratum corneum, where they mature into adults; and then mate on the skin surface.^1,4

Clinical Presentation and Sequelae—Typically, scabies presents 2 to 6 weeks after initial exposure with generalized and intense itching and inflammatory pruritic papules on the finger webs, wrists, elbows, axillae, buttocks, umbilicus, genitalia, and areolae.¹ Burrows are specific for scabies but may not always be present. Often, there are nonspecific secondary lesions, including excoriations, dermatitis, and impetiginization.

Complications of scabies can be severe, with initial colonization and infection of the skin resulting in impetigo and cellulitis. Systematic sequelae from local skin infection include post-streptococcal glomerulonephritis, rheumatic fever, and sepsis. Mortality from sepsis in scabies can be high.^3,5

Classic Crusted Scabies and Other Variants—Crusted scabies presents with psoriasiform hyperkeratotic plaques involving the hands and feet with potential nail involvement that can become more generalized.¹ Alterations in CD4⁺ T-cell function have been implicated in the development of crusted scabies, in which an excessive helper T cell (T_H2) response is elicited against the ectoparasite, which may help explain the intense pruritus of scabies.⁶ Occasionally, iatrogenic immunosuppression contributes to development of crusted scabies,¹ as was the case with our patient. However, it is rare for crusted scabies to present with erythroderma.⁷

Other atypical presentations of scabies include a seborrheic dermatitis–like presentation in infants, nodular lesions in the groin and axillae in more chronic scabies, and vesicles or bullous lesions.¹

Diagnosis—Identification of mites, eggs, or feces is necessary for definitive diagnosis of scabies.⁸ These materials can be obtained through skin scrapings with mineral oil and observed under light microscopy or direct dermoscopy. Multiple scrapings on many lesions should be performed because failure to identify mites can be common and does not rule out scabies. Dermoscopic examination of active lesions under low power also can be helpful, given that identification of dark brown triangular structures can correspond to visualization of the pigmented anterior section of the mite.^9-11 A skin biopsy can help identify mites, but histopathology often shows a nonspecific hypersensitivity reaction.¹² Therefore, empiric treatment often is necessary.

Differential Diagnosis—The differential diagnosis of erythroderma is broad and includes a drug eruption; Sézary syndrome; and pre-existing skin diseases, including psoriasis, atopic dermatitis, pityriasis rubra pilaris, pemphigus foliaceus, and bullous pemphigoid. Histopathology is critical to differentiate these diagnoses. Bullous pemphigoid and pemphigus foliaceus are immunobullous diseases that typically are positive for immunoglobulin deposition on DIF. In rare cases, scabies also can present with bullae and positive DIF test results.¹³

Treatment—First-line treatment of crusted scabies in the United States is permethrin cream 5%, followed by oral ivermectin 200 μg/kg.^4,5,14,15 Other scabicides include topicals such as benzyl benzoate 10% to 25%; precipitated sulfur 2% to 10%; crotamiton 10%; malathion 0.5%; and lindane 1%.⁵ The association of neurotoxicity with lindane has considerably reduced the drug’s use.¹

During treatment of scabies, it is important to isolate patients to mitigate the possibility of spread.⁴ Pruritus can persist for a few weeks after completion of therapy.⁵ Patients should be closely monitored to ensure that this symptom is secondary to skin inflammation and not incomplete treatment.

Treatment of crusted scabies may require repeated treatments to decrease the notable mite burden as well as the associated crusting and scale. Adding a keratolytic such as 5% to 10% salicylic acid in petrolatum to the treatment regimen may be useful for breaking up thick scale.⁵

Immunosuppression—With numerous immunomodulatory drugs for treating autoimmunity comes an increased risk for iatrogenic immunosuppression that may contribute to the development of crusted scabies.¹⁶ In a number of autoimmune diseases such as rheumatoid arthritis,^17-19 psoriasis,^20,21 pemphigus vulgaris,²² systemic lupus erythematosus,²³ systemic sclerosis,^22,24 bullous pemphigoid,^25,26 and dermatomyositis,²⁷ patients have developed crusted scabies secondary to treatment-related immunosuppression. These immunosuppressive therapies include systemic steroids,^22-24,26-31 methotrexate,²³ infliximab,¹⁸ adalimumab,²¹ toclizumab,¹⁹ and etanercept.²⁰ In a case of drug-induced Stevens-Johnson syndrome, the patient developed crusted scabies during long-term use of oral steroids.²²

Patients with a malignancy who are being treated with chemotherapy also can develop crusted scabies.²⁸ Crusted scabies has even been associated with long-term topical steroid^32-34 and topical calcineurin inhibitor use.¹⁶

Iatrogenic immunosuppression in our patient resulted from treatment of GPA with azathioprine, an immunosuppressive drug that acts as an antagonist of the breakdown of purines, leading to inhibition of DNA, RNA, and protein synthesis.³⁵ On occasion, azathioprine can induce immunosuppression in the form of myelosuppression and resulting pancytopenia, as was the case with our patient.

Conclusion

Although scabies is designated as a neglected tropical disease by the World Health Organization, it still causes a notable burden worldwide, regardless of the economics. Our case highlights an unusual presentation of scabies as erythroderma in the setting of iatrogenic immunosuppression from azathioprine use. Dermatologists should consider crusted scabies in the differential diagnosis of erythroderma, especially in immunocompromised patients, to avoid delays in diagnosis and treatment. Immunosuppressive therapy is an important mainstay in the treatment of many conditions, but it is important to consider that these medications can place patients at an increased risk for rare opportunistic infections. Therefore, patients receiving such treatment should be closely monitored.

To the Editor:

A 47-year-old man presented to the dermatology service with an asymptomatic plaque on the right thigh of 2 months’ duration. He had a medical history of HIV and Kaposi sarcoma as well as a recently relapsed primary effusion lymphoma (PEL) subsequent to an allogeneic bone marrow transplant. He initially was diagnosed with PEL 3 years prior to the current presentation during a workup for fever and weight loss. Imaging at the time demonstrated a bladder mass, which was biopsied and demonstrated PEL. Further imaging demonstrated both sinus and bone marrow involvement. Prior to dermatologic consultation, he had been treated with 6 cycles of etoposide, prednisolone, vincristine, cyclophosphamide, and doxorubicin (EPOCH); 6 cycles of brentuximab; 4 cycles of rituximab with gemcitabine and oxaliplatin; and 2 cycles of ifosfamide, carboplatin, and etoposide. Despite these therapies, he had 3 relapses, and oncology determined the need for a matched unrelated donor allogeneic stem cell transplant for his PEL.

At the time of dermatology consultation, the patient was being managed on daratumumab and bortezomib. Physical examination revealed an infiltrative plaque on the right inferomedial thigh measuring approximately 6.0 cm (largest dimension) with a small amount of peripheral scale (Figure 1). An ultrasound revealed notable subcutaneous tissue edema and increased vascularity without a discrete mass or fluid collection. A 4-mm punch biopsy demonstrated a dense infiltrate comprised of collections of histiocytes admixed with scattered plasma cells and mature lymphoid aggregates. Additionally, rare enlarged plasmablastic cells with scant basophilic cytoplasm and slightly irregular nuclear contours were visualized (Figure 2A). Immunohistochemistry was positive for CD3 with a normal CD4:CD8 ratio, CD68-highlighted histiocytes within the lymphoid aggregates, and human herpesvirus 8 (HHV-8)(or Kaposi sarcoma–associated herpesvirus) demonstrated stippled nuclear staining within the scattered large cells (Figure 2B). Epstein-Barr virus–encoded RNA staining was negative, though the area of interest was lost on deeper sectioning of the tissue block. The histopathologic findings were consistent with cutaneous extracavitary PEL. Shortly after this diagnosis, he died from disease complications.

Primary effusion lymphoma is an aggressive non-Hodgkin B-cell lymphoma that was first described by Knowles et al¹ in 1989. Primary effusion lymphoma occurs exclusively in the setting of HHV-8 infection and typically is associated with chronic immunosuppression related to HIV/AIDS. Cases that are negative for HIV-1 are rare but have been reported in organ transplant recipients and elderly men from areas with a high prevalence of HHV-8 infections. Most HIV-associated cases show concurrent Epstein-Barr virus infection, though the pathogenic meaning of this co-infection remains unclear.^2,3

Primary effusion lymphoma classically presents as an isolated effusion of malignant lymphoid cells within body cavities in the absence of solid tumor masses. The pleural, peritoneal, and pericardial spaces most commonly are involved. Extracavitary PEL, a rare variant, may present as a solid mass without effusion. In general, extracavitary tumors may occur in the setting of de novo malignancy or recurrent PEL.⁴ Cutaneous manifestations associated with extracavitary PEL are rare; 4 cases have been described in which skin lesions were the heralding sign of the disease.³ Interestingly, despite obligatory underlying HHV-8 infection, a review by Pielasinski et al³ noted only 2 patients with cutaneous PEL who had prior or concurrent Kaposi sarcoma. This heterogeneity in HHV-8–related phenotypes may be related to differences in microRNA expression, but further study is needed.⁵

The diagnosis of PEL relies on histologic, immunophenotypic, and molecular analysis of the affected tissue. The malignant cells typically are large with round to irregular nuclei. These cells may demonstrate a variety of appearances, including anaplastic, plasmablastic, and immunoblastic morphologies.^6,7 The immunophenotype displays CD45 positivity and markers of lymphocyte activation (CD30, CD38, CD71), while typical B-cell (CD19, CD20, CD79a) and T-cell (CD3, CD4, CD8) markers often are absent.^6-8 Human herpesvirus 8 detection by polymerase chain reaction testing of the peripheral blood or by immunohistochemistry staining of the affected tissue is required for diagnosis.^6,7 Epstein-Barr virus infection may be detected via in situ hybridization, though it is not required for diagnosis.

The overall prognosis for PEL is poor; Brimo et al⁶ reported a median survival of less than 6 months, and Guillet et al⁹ reported 5-year overall survival (OS) for PEL vs extracavitary PEL to be 43% vs 39%. Another review noted variation in survival contingent on the number of body cavities involved; patients with a single body cavity involved experienced a median OS of 18 months, whereas patients with multiple involved cavities experienced a median OS of 4 months,⁷ possibly due to the limited study of treatment regimens or disease aggressiveness. Even in cases of successful initial treatment, relapse within 6 to 8 months is common. Extracavitary PEL may have improved disease-free survival relative to classic PEL, though the data were less clear for OS.⁹ Limitations of the Guillet et al⁹ study included a small sample size, the impossibility to randomize to disease type, and loss of power on the log-rank test for OS in the setting of possible nonproportional hazards (crossing survival curves). Overall, prognostic differences between the groups may be challenging to ascertain until further data are obtained.

As with many HIV-associated neoplasms, antiretroviral treatment (ART) for HIV-positive patients affords a better prognosis when used in addition to therapy directed at malignancy.⁷ The general approach is for concurrent ART with systemic therapies such as rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone for the rare CD20⁺ cases, and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or dose-adjusted EPOCH therapy in the more common CD20⁻ PEL cases. Narkhede et al⁷ suggested avoidance of methotrexate in patients with effusions because of increased toxicity, but it is unclear if this recommendation is applicable in extracavitary PEL patients without an effusion. Additionally, second-line treatment modalities include radiation for solid PEL masses, HHV-8–targeted antivirals, and stem cell transplantation, though evidence is limited. Of note, there is a phase I-II trial (ClinicalTrials.gov identifier NCT02911142) ongoing for treatment-naïve PEL patients involving the experimental treatment DA-EPOCH-R plus lenalidomide, but the trial is ongoing.¹⁰

We report a case of cutaneous PEL in a patient with a history of Kaposi sarcoma. The patient’s deterioration and ultimate death despite initial treatment with EPOCH and bone marrow transplantation followed by final management with daratumumab and bortezomib confirm other reports that PEL has a poor prognosis and that optimal treatments are not well delineated for these patients. In general, the current approach is to utilize ART for HIV-positive patients and to then implement chemotherapy such as CHOP. Without continued research and careful planning of treatments, data will remain limited on how best to serve patients with PEL.

To the Editor:

A 47-year-old man presented to the dermatology service with an asymptomatic plaque on the right thigh of 2 months’ duration. He had a medical history of HIV and Kaposi sarcoma as well as a recently relapsed primary effusion lymphoma (PEL) subsequent to an allogeneic bone marrow transplant. He initially was diagnosed with PEL 3 years prior to the current presentation during a workup for fever and weight loss. Imaging at the time demonstrated a bladder mass, which was biopsied and demonstrated PEL. Further imaging demonstrated both sinus and bone marrow involvement. Prior to dermatologic consultation, he had been treated with 6 cycles of etoposide, prednisolone, vincristine, cyclophosphamide, and doxorubicin (EPOCH); 6 cycles of brentuximab; 4 cycles of rituximab with gemcitabine and oxaliplatin; and 2 cycles of ifosfamide, carboplatin, and etoposide. Despite these therapies, he had 3 relapses, and oncology determined the need for a matched unrelated donor allogeneic stem cell transplant for his PEL.

At the time of dermatology consultation, the patient was being managed on daratumumab and bortezomib. Physical examination revealed an infiltrative plaque on the right inferomedial thigh measuring approximately 6.0 cm (largest dimension) with a small amount of peripheral scale (Figure 1). An ultrasound revealed notable subcutaneous tissue edema and increased vascularity without a discrete mass or fluid collection. A 4-mm punch biopsy demonstrated a dense infiltrate comprised of collections of histiocytes admixed with scattered plasma cells and mature lymphoid aggregates. Additionally, rare enlarged plasmablastic cells with scant basophilic cytoplasm and slightly irregular nuclear contours were visualized (Figure 2A). Immunohistochemistry was positive for CD3 with a normal CD4:CD8 ratio, CD68-highlighted histiocytes within the lymphoid aggregates, and human herpesvirus 8 (HHV-8)(or Kaposi sarcoma–associated herpesvirus) demonstrated stippled nuclear staining within the scattered large cells (Figure 2B). Epstein-Barr virus–encoded RNA staining was negative, though the area of interest was lost on deeper sectioning of the tissue block. The histopathologic findings were consistent with cutaneous extracavitary PEL. Shortly after this diagnosis, he died from disease complications.

Primary effusion lymphoma is an aggressive non-Hodgkin B-cell lymphoma that was first described by Knowles et al¹ in 1989. Primary effusion lymphoma occurs exclusively in the setting of HHV-8 infection and typically is associated with chronic immunosuppression related to HIV/AIDS. Cases that are negative for HIV-1 are rare but have been reported in organ transplant recipients and elderly men from areas with a high prevalence of HHV-8 infections. Most HIV-associated cases show concurrent Epstein-Barr virus infection, though the pathogenic meaning of this co-infection remains unclear.^2,3

Primary effusion lymphoma classically presents as an isolated effusion of malignant lymphoid cells within body cavities in the absence of solid tumor masses. The pleural, peritoneal, and pericardial spaces most commonly are involved. Extracavitary PEL, a rare variant, may present as a solid mass without effusion. In general, extracavitary tumors may occur in the setting of de novo malignancy or recurrent PEL.⁴ Cutaneous manifestations associated with extracavitary PEL are rare; 4 cases have been described in which skin lesions were the heralding sign of the disease.³ Interestingly, despite obligatory underlying HHV-8 infection, a review by Pielasinski et al³ noted only 2 patients with cutaneous PEL who had prior or concurrent Kaposi sarcoma. This heterogeneity in HHV-8–related phenotypes may be related to differences in microRNA expression, but further study is needed.⁵

The diagnosis of PEL relies on histologic, immunophenotypic, and molecular analysis of the affected tissue. The malignant cells typically are large with round to irregular nuclei. These cells may demonstrate a variety of appearances, including anaplastic, plasmablastic, and immunoblastic morphologies.^6,7 The immunophenotype displays CD45 positivity and markers of lymphocyte activation (CD30, CD38, CD71), while typical B-cell (CD19, CD20, CD79a) and T-cell (CD3, CD4, CD8) markers often are absent.^6-8 Human herpesvirus 8 detection by polymerase chain reaction testing of the peripheral blood or by immunohistochemistry staining of the affected tissue is required for diagnosis.^6,7 Epstein-Barr virus infection may be detected via in situ hybridization, though it is not required for diagnosis.

The overall prognosis for PEL is poor; Brimo et al⁶ reported a median survival of less than 6 months, and Guillet et al⁹ reported 5-year overall survival (OS) for PEL vs extracavitary PEL to be 43% vs 39%. Another review noted variation in survival contingent on the number of body cavities involved; patients with a single body cavity involved experienced a median OS of 18 months, whereas patients with multiple involved cavities experienced a median OS of 4 months,⁷ possibly due to the limited study of treatment regimens or disease aggressiveness. Even in cases of successful initial treatment, relapse within 6 to 8 months is common. Extracavitary PEL may have improved disease-free survival relative to classic PEL, though the data were less clear for OS.⁹ Limitations of the Guillet et al⁹ study included a small sample size, the impossibility to randomize to disease type, and loss of power on the log-rank test for OS in the setting of possible nonproportional hazards (crossing survival curves). Overall, prognostic differences between the groups may be challenging to ascertain until further data are obtained.

As with many HIV-associated neoplasms, antiretroviral treatment (ART) for HIV-positive patients affords a better prognosis when used in addition to therapy directed at malignancy.⁷ The general approach is for concurrent ART with systemic therapies such as rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone for the rare CD20⁺ cases, and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or dose-adjusted EPOCH therapy in the more common CD20⁻ PEL cases. Narkhede et al⁷ suggested avoidance of methotrexate in patients with effusions because of increased toxicity, but it is unclear if this recommendation is applicable in extracavitary PEL patients without an effusion. Additionally, second-line treatment modalities include radiation for solid PEL masses, HHV-8–targeted antivirals, and stem cell transplantation, though evidence is limited. Of note, there is a phase I-II trial (ClinicalTrials.gov identifier NCT02911142) ongoing for treatment-naïve PEL patients involving the experimental treatment DA-EPOCH-R plus lenalidomide, but the trial is ongoing.¹⁰

We report a case of cutaneous PEL in a patient with a history of Kaposi sarcoma. The patient’s deterioration and ultimate death despite initial treatment with EPOCH and bone marrow transplantation followed by final management with daratumumab and bortezomib confirm other reports that PEL has a poor prognosis and that optimal treatments are not well delineated for these patients. In general, the current approach is to utilize ART for HIV-positive patients and to then implement chemotherapy such as CHOP. Without continued research and careful planning of treatments, data will remain limited on how best to serve patients with PEL.

To the Editor:

A 47-year-old man presented to the dermatology service with an asymptomatic plaque on the right thigh of 2 months’ duration. He had a medical history of HIV and Kaposi sarcoma as well as a recently relapsed primary effusion lymphoma (PEL) subsequent to an allogeneic bone marrow transplant. He initially was diagnosed with PEL 3 years prior to the current presentation during a workup for fever and weight loss. Imaging at the time demonstrated a bladder mass, which was biopsied and demonstrated PEL. Further imaging demonstrated both sinus and bone marrow involvement. Prior to dermatologic consultation, he had been treated with 6 cycles of etoposide, prednisolone, vincristine, cyclophosphamide, and doxorubicin (EPOCH); 6 cycles of brentuximab; 4 cycles of rituximab with gemcitabine and oxaliplatin; and 2 cycles of ifosfamide, carboplatin, and etoposide. Despite these therapies, he had 3 relapses, and oncology determined the need for a matched unrelated donor allogeneic stem cell transplant for his PEL.

At the time of dermatology consultation, the patient was being managed on daratumumab and bortezomib. Physical examination revealed an infiltrative plaque on the right inferomedial thigh measuring approximately 6.0 cm (largest dimension) with a small amount of peripheral scale (Figure 1). An ultrasound revealed notable subcutaneous tissue edema and increased vascularity without a discrete mass or fluid collection. A 4-mm punch biopsy demonstrated a dense infiltrate comprised of collections of histiocytes admixed with scattered plasma cells and mature lymphoid aggregates. Additionally, rare enlarged plasmablastic cells with scant basophilic cytoplasm and slightly irregular nuclear contours were visualized (Figure 2A). Immunohistochemistry was positive for CD3 with a normal CD4:CD8 ratio, CD68-highlighted histiocytes within the lymphoid aggregates, and human herpesvirus 8 (HHV-8)(or Kaposi sarcoma–associated herpesvirus) demonstrated stippled nuclear staining within the scattered large cells (Figure 2B). Epstein-Barr virus–encoded RNA staining was negative, though the area of interest was lost on deeper sectioning of the tissue block. The histopathologic findings were consistent with cutaneous extracavitary PEL. Shortly after this diagnosis, he died from disease complications.

Primary effusion lymphoma is an aggressive non-Hodgkin B-cell lymphoma that was first described by Knowles et al¹ in 1989. Primary effusion lymphoma occurs exclusively in the setting of HHV-8 infection and typically is associated with chronic immunosuppression related to HIV/AIDS. Cases that are negative for HIV-1 are rare but have been reported in organ transplant recipients and elderly men from areas with a high prevalence of HHV-8 infections. Most HIV-associated cases show concurrent Epstein-Barr virus infection, though the pathogenic meaning of this co-infection remains unclear.^2,3

Primary effusion lymphoma classically presents as an isolated effusion of malignant lymphoid cells within body cavities in the absence of solid tumor masses. The pleural, peritoneal, and pericardial spaces most commonly are involved. Extracavitary PEL, a rare variant, may present as a solid mass without effusion. In general, extracavitary tumors may occur in the setting of de novo malignancy or recurrent PEL.⁴ Cutaneous manifestations associated with extracavitary PEL are rare; 4 cases have been described in which skin lesions were the heralding sign of the disease.³ Interestingly, despite obligatory underlying HHV-8 infection, a review by Pielasinski et al³ noted only 2 patients with cutaneous PEL who had prior or concurrent Kaposi sarcoma. This heterogeneity in HHV-8–related phenotypes may be related to differences in microRNA expression, but further study is needed.⁵

The diagnosis of PEL relies on histologic, immunophenotypic, and molecular analysis of the affected tissue. The malignant cells typically are large with round to irregular nuclei. These cells may demonstrate a variety of appearances, including anaplastic, plasmablastic, and immunoblastic morphologies.^6,7 The immunophenotype displays CD45 positivity and markers of lymphocyte activation (CD30, CD38, CD71), while typical B-cell (CD19, CD20, CD79a) and T-cell (CD3, CD4, CD8) markers often are absent.^6-8 Human herpesvirus 8 detection by polymerase chain reaction testing of the peripheral blood or by immunohistochemistry staining of the affected tissue is required for diagnosis.^6,7 Epstein-Barr virus infection may be detected via in situ hybridization, though it is not required for diagnosis.

The overall prognosis for PEL is poor; Brimo et al⁶ reported a median survival of less than 6 months, and Guillet et al⁹ reported 5-year overall survival (OS) for PEL vs extracavitary PEL to be 43% vs 39%. Another review noted variation in survival contingent on the number of body cavities involved; patients with a single body cavity involved experienced a median OS of 18 months, whereas patients with multiple involved cavities experienced a median OS of 4 months,⁷ possibly due to the limited study of treatment regimens or disease aggressiveness. Even in cases of successful initial treatment, relapse within 6 to 8 months is common. Extracavitary PEL may have improved disease-free survival relative to classic PEL, though the data were less clear for OS.⁹ Limitations of the Guillet et al⁹ study included a small sample size, the impossibility to randomize to disease type, and loss of power on the log-rank test for OS in the setting of possible nonproportional hazards (crossing survival curves). Overall, prognostic differences between the groups may be challenging to ascertain until further data are obtained.

As with many HIV-associated neoplasms, antiretroviral treatment (ART) for HIV-positive patients affords a better prognosis when used in addition to therapy directed at malignancy.⁷ The general approach is for concurrent ART with systemic therapies such as rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone for the rare CD20⁺ cases, and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or dose-adjusted EPOCH therapy in the more common CD20⁻ PEL cases. Narkhede et al⁷ suggested avoidance of methotrexate in patients with effusions because of increased toxicity, but it is unclear if this recommendation is applicable in extracavitary PEL patients without an effusion. Additionally, second-line treatment modalities include radiation for solid PEL masses, HHV-8–targeted antivirals, and stem cell transplantation, though evidence is limited. Of note, there is a phase I-II trial (ClinicalTrials.gov identifier NCT02911142) ongoing for treatment-naïve PEL patients involving the experimental treatment DA-EPOCH-R plus lenalidomide, but the trial is ongoing.¹⁰

We report a case of cutaneous PEL in a patient with a history of Kaposi sarcoma. The patient’s deterioration and ultimate death despite initial treatment with EPOCH and bone marrow transplantation followed by final management with daratumumab and bortezomib confirm other reports that PEL has a poor prognosis and that optimal treatments are not well delineated for these patients. In general, the current approach is to utilize ART for HIV-positive patients and to then implement chemotherapy such as CHOP. Without continued research and careful planning of treatments, data will remain limited on how best to serve patients with PEL.

The Diagnosis: Syphilis

Histopathology revealed psoriasiform hyperplasia, endothelial cell swelling, and a brisk lichenoid inflammation with plasma cells (Figure, A). There also was pustular folliculitis in association with well-formed granulomatous inflammation and a prominent number of plasma cells (Figure, B). Treponema pallidum immunostaining showed numerous organisms in the epidermal and follicular epithelium. Rapid plasma reagin was found to be positive with a titer of 1:128. Evaluation for neurosyphilis through lumbar puncture was negative; the patient also was HIV negative. All of our patient’s skin lesions cleared after a 3-week course of weekly intramuscular benzathine G injections. Due to his substantial clinical improvement, the patient was subsequently lost to follow-up.

Syphilis, an infectious disease caused by the spirochete bacterium T pallidum, has a well-known natural history defined by various stages classically categorized as primary, secondary, latent, or late (tertiary).¹ The classic lesion in primary syphilis is the chancre, a painless ulcer with raised borders that develops within approximately 3 weeks following the initial inoculation.² Secondary syphilis manifests with mucocutaneous findings in up to 97% of patients, and untreated patients develop secondary syphilis at a rate of approximately 25%.³ Although mucocutaneous findings in secondary syphilis can vary widely, patients most commonly develop a diffuse maculopapular exanthem, and 40% develop mucosal findings including genital ulcers, mucous patches, and condylomata lata.¹ In latent syphilis, there is seroreactivity, but otherwise there are no clinical symptoms. A clear symptomatic history of prior primary or secondary syphilis may be known or unknown. Latent syphilis is divided into early and late phases, and the World Health Organization designates 2 years after the first suspected exposure as the cutoff point for early and late latency.⁴ During the first 4 years of latent syphilis, patients may exhibit mucocutaneous relapses. Our patient denied any sexual activity for more than 3 years prior to presentation. Because of the start of iatrogenic immunosuppression during this period, this case was classified as late latent syphilis with mucocutaneous reactivation.

Behçet disease was included within the differential diagnosis but is characterized by multiorgan systemic vasculitis that causes various mucocutaneous findings including aphthous ulcers, papulopustular lesions, and genital ulcers.⁵ Histopathologic features are nonspecific, and the clinical finding of recurrent genital and oral ulceration should be present for diagnosis. This disease predominantly occurs in East Asian or Mediterranean populations and is otherwise rare in White individuals.

SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome is a rare disorder consisting of skin, joint, and bone manifestations.⁶ Severe acne generally is accompanied by palmoplantar pustulosis along with pain and joint tenderness involving the anterior chest and axial skeleton, both of which were absent in our patient.

Pustular psoriasis can be localized or generalized. Localized presentations frequently are acral and may be associated with a variable degree of nail dystrophy and arthritis. Generalized presentations are characterized by hyperemic, well-defined patches with variable numbers of pustules.⁷ The pustules are the consequence of exuberate neutrophilic exocytosis into the epidermis and are nonfollicular.

Steroid-induced acne may be considered in the proper clinical setting of an acneform eruption with a prior history of systemic steroid treatment. However, additional findings of mucositis would not be expected, and although our patient was prescribed prednisone from his primary care physician prior to presentation to our clinic, this medication was given after the onset of the cutaneous eruption.

Syphilis commonly is referred to as the great mimicker due to its potential diverse morphologic presentations, which can involve acneform eruptions, though rare.⁸ In the setting of mucositis, generalized acneform eruptions should raise suspicion for the possibility of syphilis, even in the absence of other more classic cutaneous features.

The Diagnosis: Syphilis

Histopathology revealed psoriasiform hyperplasia, endothelial cell swelling, and a brisk lichenoid inflammation with plasma cells (Figure, A). There also was pustular folliculitis in association with well-formed granulomatous inflammation and a prominent number of plasma cells (Figure, B). Treponema pallidum immunostaining showed numerous organisms in the epidermal and follicular epithelium. Rapid plasma reagin was found to be positive with a titer of 1:128. Evaluation for neurosyphilis through lumbar puncture was negative; the patient also was HIV negative. All of our patient’s skin lesions cleared after a 3-week course of weekly intramuscular benzathine G injections. Due to his substantial clinical improvement, the patient was subsequently lost to follow-up.

Syphilis, an infectious disease caused by the spirochete bacterium T pallidum, has a well-known natural history defined by various stages classically categorized as primary, secondary, latent, or late (tertiary).¹ The classic lesion in primary syphilis is the chancre, a painless ulcer with raised borders that develops within approximately 3 weeks following the initial inoculation.² Secondary syphilis manifests with mucocutaneous findings in up to 97% of patients, and untreated patients develop secondary syphilis at a rate of approximately 25%.³ Although mucocutaneous findings in secondary syphilis can vary widely, patients most commonly develop a diffuse maculopapular exanthem, and 40% develop mucosal findings including genital ulcers, mucous patches, and condylomata lata.¹ In latent syphilis, there is seroreactivity, but otherwise there are no clinical symptoms. A clear symptomatic history of prior primary or secondary syphilis may be known or unknown. Latent syphilis is divided into early and late phases, and the World Health Organization designates 2 years after the first suspected exposure as the cutoff point for early and late latency.⁴ During the first 4 years of latent syphilis, patients may exhibit mucocutaneous relapses. Our patient denied any sexual activity for more than 3 years prior to presentation. Because of the start of iatrogenic immunosuppression during this period, this case was classified as late latent syphilis with mucocutaneous reactivation.

Behçet disease was included within the differential diagnosis but is characterized by multiorgan systemic vasculitis that causes various mucocutaneous findings including aphthous ulcers, papulopustular lesions, and genital ulcers.⁵ Histopathologic features are nonspecific, and the clinical finding of recurrent genital and oral ulceration should be present for diagnosis. This disease predominantly occurs in East Asian or Mediterranean populations and is otherwise rare in White individuals.

SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome is a rare disorder consisting of skin, joint, and bone manifestations.⁶ Severe acne generally is accompanied by palmoplantar pustulosis along with pain and joint tenderness involving the anterior chest and axial skeleton, both of which were absent in our patient.

Pustular psoriasis can be localized or generalized. Localized presentations frequently are acral and may be associated with a variable degree of nail dystrophy and arthritis. Generalized presentations are characterized by hyperemic, well-defined patches with variable numbers of pustules.⁷ The pustules are the consequence of exuberate neutrophilic exocytosis into the epidermis and are nonfollicular.

Steroid-induced acne may be considered in the proper clinical setting of an acneform eruption with a prior history of systemic steroid treatment. However, additional findings of mucositis would not be expected, and although our patient was prescribed prednisone from his primary care physician prior to presentation to our clinic, this medication was given after the onset of the cutaneous eruption.

Syphilis commonly is referred to as the great mimicker due to its potential diverse morphologic presentations, which can involve acneform eruptions, though rare.⁸ In the setting of mucositis, generalized acneform eruptions should raise suspicion for the possibility of syphilis, even in the absence of other more classic cutaneous features.

The Diagnosis: Syphilis

Histopathology revealed psoriasiform hyperplasia, endothelial cell swelling, and a brisk lichenoid inflammation with plasma cells (Figure, A). There also was pustular folliculitis in association with well-formed granulomatous inflammation and a prominent number of plasma cells (Figure, B). Treponema pallidum immunostaining showed numerous organisms in the epidermal and follicular epithelium. Rapid plasma reagin was found to be positive with a titer of 1:128. Evaluation for neurosyphilis through lumbar puncture was negative; the patient also was HIV negative. All of our patient’s skin lesions cleared after a 3-week course of weekly intramuscular benzathine G injections. Due to his substantial clinical improvement, the patient was subsequently lost to follow-up.

Syphilis, an infectious disease caused by the spirochete bacterium T pallidum, has a well-known natural history defined by various stages classically categorized as primary, secondary, latent, or late (tertiary).¹ The classic lesion in primary syphilis is the chancre, a painless ulcer with raised borders that develops within approximately 3 weeks following the initial inoculation.² Secondary syphilis manifests with mucocutaneous findings in up to 97% of patients, and untreated patients develop secondary syphilis at a rate of approximately 25%.³ Although mucocutaneous findings in secondary syphilis can vary widely, patients most commonly develop a diffuse maculopapular exanthem, and 40% develop mucosal findings including genital ulcers, mucous patches, and condylomata lata.¹ In latent syphilis, there is seroreactivity, but otherwise there are no clinical symptoms. A clear symptomatic history of prior primary or secondary syphilis may be known or unknown. Latent syphilis is divided into early and late phases, and the World Health Organization designates 2 years after the first suspected exposure as the cutoff point for early and late latency.⁴ During the first 4 years of latent syphilis, patients may exhibit mucocutaneous relapses. Our patient denied any sexual activity for more than 3 years prior to presentation. Because of the start of iatrogenic immunosuppression during this period, this case was classified as late latent syphilis with mucocutaneous reactivation.

Behçet disease was included within the differential diagnosis but is characterized by multiorgan systemic vasculitis that causes various mucocutaneous findings including aphthous ulcers, papulopustular lesions, and genital ulcers.⁵ Histopathologic features are nonspecific, and the clinical finding of recurrent genital and oral ulceration should be present for diagnosis. This disease predominantly occurs in East Asian or Mediterranean populations and is otherwise rare in White individuals.

SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome is a rare disorder consisting of skin, joint, and bone manifestations.⁶ Severe acne generally is accompanied by palmoplantar pustulosis along with pain and joint tenderness involving the anterior chest and axial skeleton, both of which were absent in our patient.

Pustular psoriasis can be localized or generalized. Localized presentations frequently are acral and may be associated with a variable degree of nail dystrophy and arthritis. Generalized presentations are characterized by hyperemic, well-defined patches with variable numbers of pustules.⁷ The pustules are the consequence of exuberate neutrophilic exocytosis into the epidermis and are nonfollicular.

Steroid-induced acne may be considered in the proper clinical setting of an acneform eruption with a prior history of systemic steroid treatment. However, additional findings of mucositis would not be expected, and although our patient was prescribed prednisone from his primary care physician prior to presentation to our clinic, this medication was given after the onset of the cutaneous eruption.

Syphilis commonly is referred to as the great mimicker due to its potential diverse morphologic presentations, which can involve acneform eruptions, though rare.⁸ In the setting of mucositis, generalized acneform eruptions should raise suspicion for the possibility of syphilis, even in the absence of other more classic cutaneous features.

Last month, I described a 28-year-old patient with a history of injection drug use who presented with pain in his left forearm. His history showed that, within the past 2 years, he’d been seen for cutaneous infections multiple times as an outpatient and in the emergency department. His records indicated that he was diagnosed with a penicillin allergy as a child when he developed a rash after receiving amoxicillin. I believed the next course of action should be to test for a penicillin allergy with an oral amoxicillin challenge.
 

Thank you for your excellent questions regarding this case. Great to hear the enthusiasm for testing for penicillin allergy!

One question focused on the course of action in the case of a mild or moderate IgE-mediated reaction after a single dose test with amoxicillin. Treatment for these reactions should include an antihistamine. I would reserve intravenous antihistamines for more severe cases, which also require treatment with a course of corticosteroids. However, the risk for a moderate to severe reaction to amoxicillin on retesting is quite low.

Clinicians need to exercise caution in the use of systemic corticosteroids. These drugs can be lifesaving, but even short courses of corticosteroids are associated with potentially serious adverse events. In a review of adverse events associated with short-course systemic corticosteroids among children, the rate of vomiting was 5.4%; behavioral change, 4.7%; and sleep disturbance, 4.3%. One child died after contracting herpes zoster, more than one-third of children developed elevated blood pressure, and 81.1% had evidence of suppression of the hypothalamic-pituitary-adrenal axis.

Among adults, short courses of systemic corticosteroids are associated with acute increases in the risks for gastrointestinal bleeding and hypertension. Cumulative exposure to short courses of corticosteroids over time results in higher risks for obesity, type 2 diabetes, and osteoporosis.

Another question prompted by this young man’s case focused on the durability of IgE reactions against penicillin. The IgE response to penicillin does indeed wane over time; 80% of patients with a previous true penicillin allergy can tolerate the antibiotic after 10 years. Thus, about 95% of patients with a remote history of penicillin allergy are tolerant of penicillin, and testing can be performed using the algorithm described.

Clinicians should avoid applying current guidelines for the evaluation of patients with penicillin allergy to other common drug allergies. The overall prevalence of sulfonamide allergy is 3%-8%, and the vast majority of these reactions follow treatment with trimethoprim-sulfamethoxazole. Sulfa allergy is even more common among persons living with HIV infection. The natural history of sulfa allergy is not as well established as penicillin allergy. Allergy testing is encouraged in these cases. Graded oral challenge testing is best reserved for patients who are unlikely to have a true sulfa allergy based on their history.

A version of this article first appeared on Medscape.com.

Last month, I described a 28-year-old patient with a history of injection drug use who presented with pain in his left forearm. His history showed that, within the past 2 years, he’d been seen for cutaneous infections multiple times as an outpatient and in the emergency department. His records indicated that he was diagnosed with a penicillin allergy as a child when he developed a rash after receiving amoxicillin. I believed the next course of action should be to test for a penicillin allergy with an oral amoxicillin challenge.
 

Thank you for your excellent questions regarding this case. Great to hear the enthusiasm for testing for penicillin allergy!

One question focused on the course of action in the case of a mild or moderate IgE-mediated reaction after a single dose test with amoxicillin. Treatment for these reactions should include an antihistamine. I would reserve intravenous antihistamines for more severe cases, which also require treatment with a course of corticosteroids. However, the risk for a moderate to severe reaction to amoxicillin on retesting is quite low.

Clinicians need to exercise caution in the use of systemic corticosteroids. These drugs can be lifesaving, but even short courses of corticosteroids are associated with potentially serious adverse events. In a review of adverse events associated with short-course systemic corticosteroids among children, the rate of vomiting was 5.4%; behavioral change, 4.7%; and sleep disturbance, 4.3%. One child died after contracting herpes zoster, more than one-third of children developed elevated blood pressure, and 81.1% had evidence of suppression of the hypothalamic-pituitary-adrenal axis.

Among adults, short courses of systemic corticosteroids are associated with acute increases in the risks for gastrointestinal bleeding and hypertension. Cumulative exposure to short courses of corticosteroids over time results in higher risks for obesity, type 2 diabetes, and osteoporosis.

Another question prompted by this young man’s case focused on the durability of IgE reactions against penicillin. The IgE response to penicillin does indeed wane over time; 80% of patients with a previous true penicillin allergy can tolerate the antibiotic after 10 years. Thus, about 95% of patients with a remote history of penicillin allergy are tolerant of penicillin, and testing can be performed using the algorithm described.

Clinicians should avoid applying current guidelines for the evaluation of patients with penicillin allergy to other common drug allergies. The overall prevalence of sulfonamide allergy is 3%-8%, and the vast majority of these reactions follow treatment with trimethoprim-sulfamethoxazole. Sulfa allergy is even more common among persons living with HIV infection. The natural history of sulfa allergy is not as well established as penicillin allergy. Allergy testing is encouraged in these cases. Graded oral challenge testing is best reserved for patients who are unlikely to have a true sulfa allergy based on their history.

A version of this article first appeared on Medscape.com.

Last month, I described a 28-year-old patient with a history of injection drug use who presented with pain in his left forearm. His history showed that, within the past 2 years, he’d been seen for cutaneous infections multiple times as an outpatient and in the emergency department. His records indicated that he was diagnosed with a penicillin allergy as a child when he developed a rash after receiving amoxicillin. I believed the next course of action should be to test for a penicillin allergy with an oral amoxicillin challenge.
 

Thank you for your excellent questions regarding this case. Great to hear the enthusiasm for testing for penicillin allergy!

One question focused on the course of action in the case of a mild or moderate IgE-mediated reaction after a single dose test with amoxicillin. Treatment for these reactions should include an antihistamine. I would reserve intravenous antihistamines for more severe cases, which also require treatment with a course of corticosteroids. However, the risk for a moderate to severe reaction to amoxicillin on retesting is quite low.

Clinicians need to exercise caution in the use of systemic corticosteroids. These drugs can be lifesaving, but even short courses of corticosteroids are associated with potentially serious adverse events. In a review of adverse events associated with short-course systemic corticosteroids among children, the rate of vomiting was 5.4%; behavioral change, 4.7%; and sleep disturbance, 4.3%. One child died after contracting herpes zoster, more than one-third of children developed elevated blood pressure, and 81.1% had evidence of suppression of the hypothalamic-pituitary-adrenal axis.

Among adults, short courses of systemic corticosteroids are associated with acute increases in the risks for gastrointestinal bleeding and hypertension. Cumulative exposure to short courses of corticosteroids over time results in higher risks for obesity, type 2 diabetes, and osteoporosis.

Another question prompted by this young man’s case focused on the durability of IgE reactions against penicillin. The IgE response to penicillin does indeed wane over time; 80% of patients with a previous true penicillin allergy can tolerate the antibiotic after 10 years. Thus, about 95% of patients with a remote history of penicillin allergy are tolerant of penicillin, and testing can be performed using the algorithm described.

Clinicians should avoid applying current guidelines for the evaluation of patients with penicillin allergy to other common drug allergies. The overall prevalence of sulfonamide allergy is 3%-8%, and the vast majority of these reactions follow treatment with trimethoprim-sulfamethoxazole. Sulfa allergy is even more common among persons living with HIV infection. The natural history of sulfa allergy is not as well established as penicillin allergy. Allergy testing is encouraged in these cases. Graded oral challenge testing is best reserved for patients who are unlikely to have a true sulfa allergy based on their history.

A version of this article first appeared on Medscape.com.