Cutis

To the Editor:

Kaposi sarcoma (KS) is a rare angioproliferative disorder associated with human herpesvirus 8 (HHV-8) infection.¹ There are 4 main recognized epidemiologic forms of KS: classic, endemic, epidemic, and iatrogenic (Table). Nonepidemic KS is a recently described rare fifth type of KS that occurs in a subset of patients who do not fit the other classifications—HIV-negative patients without detectable cellular or humoral immune deficiency. This subset has been described as clinically similar to classic KS with limited disease but occurring in younger men.^2,3 We describe a case of nonepidemic KS in a Middle Eastern heterosexual immunocompetent man.

A 30-year-old man presented for evaluation of a growth on the nose of 3 months’ duration. The patient reported being otherwise healthy and was not taking long-term medications. He denied a history of malignancy, organ transplant, or immunosuppressive therapy. He was born in Syria and lived in Thailand for several years prior to moving to the United States. HIV testing 6 months prior to presentation was negative. He denied fever, chills, lymphadenopathy, shortness of breath, hemoptysis, melena, hematochezia, and intravenous drug use.

Physical examination revealed a solitary shiny, 7-mm, pink-red papule on the nasal dorsum (Figure 1). No other skin or mucosal lesions were identified. There was no cervical, axillary, or inguinal lymphadenopathy. A laboratory workup consisting of serum immunoglobulins and serum protein electrophoresis was unremarkable. Tests for HIV-1 and HIV-2 as well as human T-lymphotropic virus 1 and 2 were negative. The CD4 and CD8 counts were within reference range. Histopathology of a shave biopsy revealed a dermal spindle cell proliferation arranged in short intersecting fascicles and admixed with plasma cells and occasional mitotic figures. Immunohistochemistry showed that the spindle cells stained positive for CD34, CD31, and HHV-8 (Figure 2). The lesion resolved after treatment with cryotherapy. Repeat HIV testing 3 months later was negative. No recurrence or new lesions were identified at 3-month follow-up.

Similar to the other subtypes of KS, the nonepidemic form is dependent on HHV-8 infection, which is more commonly transmitted via saliva and sexual contact.^3,4 After infecting endothelial cells, HHV-8 is believed to activate the mammalian target of rapamycin and nuclear factor κB pathways, resulting in aberrant cellular differentiation and neoangiogenesis through upregulation of vascular endothelial growth factor and basic fibroblast growth factor.^2,4 Similar to what is seen with other herpesviruses, HHV-8 infection typically is lifelong due to the virus’s ability to establish latency within human B cells and endothelial cells as well as undergo sporadic bouts of lytic reactivation during its life cycle.⁴

Nonepidemic KS resembles other variants clinically, manifesting as erythematous or violaceous, painless, nonblanchable macules, papules, and nodules.¹ Early lesions often are asymptomatic and can manifest as pigmented macules or small papules that vary from pale pink to vivid purple. Nodules also can occur and be exophytic and ulcerated with bleeding.¹ Secondary lymphoproliferative disorders including Castleman disease and lymphoma have been reported.^2,5

In contrast to other types of KS in which pulmonary or gastrointestinal tract lesions can develop with hemoptysis or hematochezia, mucocutaneous and visceral lesions rarely are reported in nonepidemic KS.³ Lymphedema, a feature associated with endemic KS, is notably absent in nonepidemic KS.^1,3

The differential diagnosis applicable to all KS subtypes includes other vascular lesions such as angiomatosis and angiosarcoma. Histopathologic analysis is critical to differentiate KS from these conditions; visual diagnosis alone has only an 80% positive predictive value for KS.⁴ The histopathologic presentation of KS is a vascular proliferation in the dermis accompanied by an increased number of vessels without an endothelial cell lining.⁴ Spindle cell proliferation also is a common feature and is considered to be the KS tumor cell. Immunostaining for HHV-8 antigen as well as for CD31 and CD34 can be used to confirm the diagnosis.⁴

The management and prognosis of KS depends on the epidemiologic subtype. Classic and nonepidemic KS generally are indolent with a good prognosis. Periodic follow-up is recommended because of an increased risk for secondary malignancy such as lymphoma. The treatment of epidemic KS is highly active antiretroviral therapy. Similarly, reduction of immunosuppression is warranted for iatrogenic KS. For all types, cutaneous lesions can be treated with local excision, cryosurgery, radiation, chemotherapy, intralesional vincristine, or a topical agent such as imiquimod or alitretinoin.⁶

To the Editor:

Kaposi sarcoma (KS) is a rare angioproliferative disorder associated with human herpesvirus 8 (HHV-8) infection.¹ There are 4 main recognized epidemiologic forms of KS: classic, endemic, epidemic, and iatrogenic (Table). Nonepidemic KS is a recently described rare fifth type of KS that occurs in a subset of patients who do not fit the other classifications—HIV-negative patients without detectable cellular or humoral immune deficiency. This subset has been described as clinically similar to classic KS with limited disease but occurring in younger men.^2,3 We describe a case of nonepidemic KS in a Middle Eastern heterosexual immunocompetent man.

A 30-year-old man presented for evaluation of a growth on the nose of 3 months’ duration. The patient reported being otherwise healthy and was not taking long-term medications. He denied a history of malignancy, organ transplant, or immunosuppressive therapy. He was born in Syria and lived in Thailand for several years prior to moving to the United States. HIV testing 6 months prior to presentation was negative. He denied fever, chills, lymphadenopathy, shortness of breath, hemoptysis, melena, hematochezia, and intravenous drug use.

Physical examination revealed a solitary shiny, 7-mm, pink-red papule on the nasal dorsum (Figure 1). No other skin or mucosal lesions were identified. There was no cervical, axillary, or inguinal lymphadenopathy. A laboratory workup consisting of serum immunoglobulins and serum protein electrophoresis was unremarkable. Tests for HIV-1 and HIV-2 as well as human T-lymphotropic virus 1 and 2 were negative. The CD4 and CD8 counts were within reference range. Histopathology of a shave biopsy revealed a dermal spindle cell proliferation arranged in short intersecting fascicles and admixed with plasma cells and occasional mitotic figures. Immunohistochemistry showed that the spindle cells stained positive for CD34, CD31, and HHV-8 (Figure 2). The lesion resolved after treatment with cryotherapy. Repeat HIV testing 3 months later was negative. No recurrence or new lesions were identified at 3-month follow-up.

Similar to the other subtypes of KS, the nonepidemic form is dependent on HHV-8 infection, which is more commonly transmitted via saliva and sexual contact.^3,4 After infecting endothelial cells, HHV-8 is believed to activate the mammalian target of rapamycin and nuclear factor κB pathways, resulting in aberrant cellular differentiation and neoangiogenesis through upregulation of vascular endothelial growth factor and basic fibroblast growth factor.^2,4 Similar to what is seen with other herpesviruses, HHV-8 infection typically is lifelong due to the virus’s ability to establish latency within human B cells and endothelial cells as well as undergo sporadic bouts of lytic reactivation during its life cycle.⁴

Nonepidemic KS resembles other variants clinically, manifesting as erythematous or violaceous, painless, nonblanchable macules, papules, and nodules.¹ Early lesions often are asymptomatic and can manifest as pigmented macules or small papules that vary from pale pink to vivid purple. Nodules also can occur and be exophytic and ulcerated with bleeding.¹ Secondary lymphoproliferative disorders including Castleman disease and lymphoma have been reported.^2,5

In contrast to other types of KS in which pulmonary or gastrointestinal tract lesions can develop with hemoptysis or hematochezia, mucocutaneous and visceral lesions rarely are reported in nonepidemic KS.³ Lymphedema, a feature associated with endemic KS, is notably absent in nonepidemic KS.^1,3

The differential diagnosis applicable to all KS subtypes includes other vascular lesions such as angiomatosis and angiosarcoma. Histopathologic analysis is critical to differentiate KS from these conditions; visual diagnosis alone has only an 80% positive predictive value for KS.⁴ The histopathologic presentation of KS is a vascular proliferation in the dermis accompanied by an increased number of vessels without an endothelial cell lining.⁴ Spindle cell proliferation also is a common feature and is considered to be the KS tumor cell. Immunostaining for HHV-8 antigen as well as for CD31 and CD34 can be used to confirm the diagnosis.⁴

The management and prognosis of KS depends on the epidemiologic subtype. Classic and nonepidemic KS generally are indolent with a good prognosis. Periodic follow-up is recommended because of an increased risk for secondary malignancy such as lymphoma. The treatment of epidemic KS is highly active antiretroviral therapy. Similarly, reduction of immunosuppression is warranted for iatrogenic KS. For all types, cutaneous lesions can be treated with local excision, cryosurgery, radiation, chemotherapy, intralesional vincristine, or a topical agent such as imiquimod or alitretinoin.⁶

To the Editor:

Kaposi sarcoma (KS) is a rare angioproliferative disorder associated with human herpesvirus 8 (HHV-8) infection.¹ There are 4 main recognized epidemiologic forms of KS: classic, endemic, epidemic, and iatrogenic (Table). Nonepidemic KS is a recently described rare fifth type of KS that occurs in a subset of patients who do not fit the other classifications—HIV-negative patients without detectable cellular or humoral immune deficiency. This subset has been described as clinically similar to classic KS with limited disease but occurring in younger men.^2,3 We describe a case of nonepidemic KS in a Middle Eastern heterosexual immunocompetent man.

A 30-year-old man presented for evaluation of a growth on the nose of 3 months’ duration. The patient reported being otherwise healthy and was not taking long-term medications. He denied a history of malignancy, organ transplant, or immunosuppressive therapy. He was born in Syria and lived in Thailand for several years prior to moving to the United States. HIV testing 6 months prior to presentation was negative. He denied fever, chills, lymphadenopathy, shortness of breath, hemoptysis, melena, hematochezia, and intravenous drug use.

Physical examination revealed a solitary shiny, 7-mm, pink-red papule on the nasal dorsum (Figure 1). No other skin or mucosal lesions were identified. There was no cervical, axillary, or inguinal lymphadenopathy. A laboratory workup consisting of serum immunoglobulins and serum protein electrophoresis was unremarkable. Tests for HIV-1 and HIV-2 as well as human T-lymphotropic virus 1 and 2 were negative. The CD4 and CD8 counts were within reference range. Histopathology of a shave biopsy revealed a dermal spindle cell proliferation arranged in short intersecting fascicles and admixed with plasma cells and occasional mitotic figures. Immunohistochemistry showed that the spindle cells stained positive for CD34, CD31, and HHV-8 (Figure 2). The lesion resolved after treatment with cryotherapy. Repeat HIV testing 3 months later was negative. No recurrence or new lesions were identified at 3-month follow-up.

Similar to the other subtypes of KS, the nonepidemic form is dependent on HHV-8 infection, which is more commonly transmitted via saliva and sexual contact.^3,4 After infecting endothelial cells, HHV-8 is believed to activate the mammalian target of rapamycin and nuclear factor κB pathways, resulting in aberrant cellular differentiation and neoangiogenesis through upregulation of vascular endothelial growth factor and basic fibroblast growth factor.^2,4 Similar to what is seen with other herpesviruses, HHV-8 infection typically is lifelong due to the virus’s ability to establish latency within human B cells and endothelial cells as well as undergo sporadic bouts of lytic reactivation during its life cycle.⁴

Nonepidemic KS resembles other variants clinically, manifesting as erythematous or violaceous, painless, nonblanchable macules, papules, and nodules.¹ Early lesions often are asymptomatic and can manifest as pigmented macules or small papules that vary from pale pink to vivid purple. Nodules also can occur and be exophytic and ulcerated with bleeding.¹ Secondary lymphoproliferative disorders including Castleman disease and lymphoma have been reported.^2,5

In contrast to other types of KS in which pulmonary or gastrointestinal tract lesions can develop with hemoptysis or hematochezia, mucocutaneous and visceral lesions rarely are reported in nonepidemic KS.³ Lymphedema, a feature associated with endemic KS, is notably absent in nonepidemic KS.^1,3

The differential diagnosis applicable to all KS subtypes includes other vascular lesions such as angiomatosis and angiosarcoma. Histopathologic analysis is critical to differentiate KS from these conditions; visual diagnosis alone has only an 80% positive predictive value for KS.⁴ The histopathologic presentation of KS is a vascular proliferation in the dermis accompanied by an increased number of vessels without an endothelial cell lining.⁴ Spindle cell proliferation also is a common feature and is considered to be the KS tumor cell. Immunostaining for HHV-8 antigen as well as for CD31 and CD34 can be used to confirm the diagnosis.⁴

The management and prognosis of KS depends on the epidemiologic subtype. Classic and nonepidemic KS generally are indolent with a good prognosis. Periodic follow-up is recommended because of an increased risk for secondary malignancy such as lymphoma. The treatment of epidemic KS is highly active antiretroviral therapy. Similarly, reduction of immunosuppression is warranted for iatrogenic KS. For all types, cutaneous lesions can be treated with local excision, cryosurgery, radiation, chemotherapy, intralesional vincristine, or a topical agent such as imiquimod or alitretinoin.⁶

The Diagnosis: Calcific Uremic Arteriolopathy

Computed tomography of the abdomen and pelvis with contrast revealed a right complex renal cyst with peripheral calcification; computed tomography of the head without contrast revealed atherosclerotic changes with calcification of the intracranial arteries, vertebral basilar arteries, and bilateral branches of the ophthalmic artery. Histopathology revealed occlusive vasculopathy with epidermal ischemic changes as well as dermal and subcutaneous vascular congestion and small thrombi. Within the subcutis, there were tiny stippled calcium deposits within very small vascular lumina (Figure). The combination of clinical and histological findings was highly suggestive of calcific uremic arteriolopathy, and the patient was transitioned to hemodialysis against a low-calcium bath to avoid hypercalcemia. Unfortunately, she developed complications related to sepsis and experienced worsening mentation. After a discussion with palliative care, the patient was transitioned to comfort measures and discharged home on hospice 1 week after the biopsy at her family’s request.

Calcific uremic arteriolopathy (also known as calciphylaxis) is a rare, life-threatening syndrome of widespread vascular calcification leading to microvascular occlusion within the dermis and subcutaneous tissues.¹ Clinically, it typically manifests as severely painful, purpuric skin lesions that evolve through phases of blistering, ulceration, and ultimately visible skin necrosis.² The pain likely is a consequence of ischemia and nociceptive activation and often may precede any visibly apparent skin lesions.³ Risk factors associated with the development of this condition include female sex; history of diabetes mellitus, obesity, rapid weight loss, or end-stage renal disease; abnormalities in calcium and phosphorus homeostasis; and vitamin K deficiency.^1,3 It is more prevalent in patients on peritoneal dialysis compared to hemodialysis.⁴

Calciphylaxis is diagnosed with combined clinical and histopathological evidence. Laboratory test abnormalities are not specific for disease; therefore, skin biopsy is the standard confirmatory test, though its practice is contentious due to the risk for nonhealing ulceration and increasing risk for infection.¹ Findings suggestive of disease include focal to diffuse calcification (intravascular, extravascular, or perieccrine), superficial fat calcium deposition, mid panniculus calcium deposition, mid panniculus vascular thrombi, and focal to diffuse angioplasia.⁵ The hallmark feature is diffuse calcification of small capillaries in adipose tissue.⁶

The mortality rate associated with this disease is high—a 6-month mortality rate of 27% to 43% has been reported from the time of diagnosis^7-9—which often is related to subsequent superimposed infections patients acquire from necrotic skin tissue.² The disease also carries high morbidity, with patients experiencing frequent hospitalizations related to pain, infections, and nonhealing wounds.⁶ There is no standard treatment, and trials have been limited to small sample sizes. A multidisciplinary treatment approach is essential to maximize outcomes, which includes wound care, risk factor modification, analgesia, and symptomatic management strategies.^1,2,6

Some pharmacologic agents have received noteworthy attention in treating calciphylaxis, including sodium thiosulfate (STS), bisphosphonates, and vitamin K supplementation.¹ The strongest evidence supporting the use of STS comes from 2 trials involving 53 and 27 dialysis patients, with complete remission in 14 (26%) and 14 (52%) patients, respectively.^10,11 However, these trials did not include control groups to compare outcomes, and mortality rates were similarly high among partial responders and nonresponders compared with patients not treated with STS. A 2018 systematic review failed to assess the efficacy of STS alone for the treatment of calciphylaxis but suggested there may be a future role for it, with 251 of 358 patients (70.1%) responding to therapy.¹²

Erythema ab igne is a cutaneous reaction related to long-term heat exposure, often from electronic devices such as laptops, heating pads, space heaters, or hot-water bottles.^13,14 Clinically, this rash appears as an erythematous, purpuric, or hyperpigmented reticular dermatosis that is below the clinical threshold to define a thermal burn.¹³ Lesions often are seen on the anterior thighs or across the abdomen.¹⁵ There usually are no long-term clinical sequelae; however, rare malignant transformation has been documented in cases of atrophy or nonhealing ulceration.¹⁶ Treatment is supportive with removal of the offending agent, but hyperpigmentation may persist for months to years.¹⁴

Livedo reticularis is a cutaneous pattern of mottled violaceous or hyperpigmented changes that often signifies underlying vascular dermal changes.¹⁷ It can be seen in various pathologic states, including vasculitis, autoimmune disease, connective tissue disease, neurologic disease, infection, or malignancy, or it can be drug induced.¹⁸ There are no pathognomonic microscopic changes, as the histology will drastically differ based on the etiology. Workup can be extensive; cues to the underlying pathology should be sought based on the patient’s history and concurrent presenting symptoms. Livedo reticularis is the most common dermatologic finding in patients with antiphospholipid syndrome, and workup should include antiphospholipid antibodies (eg, lupus anticoagulant, anticardiolipin, anti–beta-2-glycoproteins) as well as lupus testing (eg, antinuclear antibodies, anti– double-stranded DNA).¹⁹ Treatment is targeted at the underlying disease process.

Cryoglobulinemia is a disease characterized by abnormal serum immunoglobulins that precipitate at cold temperatures and is further subcategorized by the type of complexes that are deposited.²⁰ Type I represents purely monoclonal cryoglobulins, type III purely polyclonal, and type II a mixed picture. Clinical manifestations arise from excessive deposition of these proteins in the skin, joints, peripheral vasculature, and kidneys leading to purpuric skin lesions, chronic ulceration, arthralgia, and glomerulonephritis. Cutaneous findings may include erythematous to purpuric macular or papular changes with or without the presence of ulceration, infarction, or hemorrhagic crusting.²¹ Systemic disease often underlies a diagnosis, and further investigation for hepatitis C virus, connective tissue disease, and hematologic malignancies should be considered.²⁰ Treatment is targeted at underlying systemic disease, such as antiviral treatment for hepatitis or chemotherapeutic regimens for hematologic disease.²²

Polyarteritis nodosa is a systemic necrotizing vasculitis that typically involves small- to medium-sized arteries. Cutaneous manifestations often include subcutaneous nodules, livedo reticularis, and ulcerations most found on the lower extremities.²³ Systemic symptoms including fever, myalgia, arthralgia, and neuropathy often are present. Characteristic histopathology findings include inflammation and destruction of medium-sized arteries at the junctional zone of the dermis and subcutis along with microaneurysms along the vessels.²⁴ Treatment is based on the severity of disease, with localized cutaneous disease often being controlled with topical steroids and anti-inflammatory agents, while more widespread disease requires immunosuppression with systemic steroids, hydroxychloroquine, azathioprine, methotrexate, mycophenolate mofetil, or intravenous immunoglobulins.²³

The Diagnosis: Calcific Uremic Arteriolopathy

Computed tomography of the abdomen and pelvis with contrast revealed a right complex renal cyst with peripheral calcification; computed tomography of the head without contrast revealed atherosclerotic changes with calcification of the intracranial arteries, vertebral basilar arteries, and bilateral branches of the ophthalmic artery. Histopathology revealed occlusive vasculopathy with epidermal ischemic changes as well as dermal and subcutaneous vascular congestion and small thrombi. Within the subcutis, there were tiny stippled calcium deposits within very small vascular lumina (Figure). The combination of clinical and histological findings was highly suggestive of calcific uremic arteriolopathy, and the patient was transitioned to hemodialysis against a low-calcium bath to avoid hypercalcemia. Unfortunately, she developed complications related to sepsis and experienced worsening mentation. After a discussion with palliative care, the patient was transitioned to comfort measures and discharged home on hospice 1 week after the biopsy at her family’s request.

Calcific uremic arteriolopathy (also known as calciphylaxis) is a rare, life-threatening syndrome of widespread vascular calcification leading to microvascular occlusion within the dermis and subcutaneous tissues.¹ Clinically, it typically manifests as severely painful, purpuric skin lesions that evolve through phases of blistering, ulceration, and ultimately visible skin necrosis.² The pain likely is a consequence of ischemia and nociceptive activation and often may precede any visibly apparent skin lesions.³ Risk factors associated with the development of this condition include female sex; history of diabetes mellitus, obesity, rapid weight loss, or end-stage renal disease; abnormalities in calcium and phosphorus homeostasis; and vitamin K deficiency.^1,3 It is more prevalent in patients on peritoneal dialysis compared to hemodialysis.⁴

Calciphylaxis is diagnosed with combined clinical and histopathological evidence. Laboratory test abnormalities are not specific for disease; therefore, skin biopsy is the standard confirmatory test, though its practice is contentious due to the risk for nonhealing ulceration and increasing risk for infection.¹ Findings suggestive of disease include focal to diffuse calcification (intravascular, extravascular, or perieccrine), superficial fat calcium deposition, mid panniculus calcium deposition, mid panniculus vascular thrombi, and focal to diffuse angioplasia.⁵ The hallmark feature is diffuse calcification of small capillaries in adipose tissue.⁶

The mortality rate associated with this disease is high—a 6-month mortality rate of 27% to 43% has been reported from the time of diagnosis^7-9—which often is related to subsequent superimposed infections patients acquire from necrotic skin tissue.² The disease also carries high morbidity, with patients experiencing frequent hospitalizations related to pain, infections, and nonhealing wounds.⁶ There is no standard treatment, and trials have been limited to small sample sizes. A multidisciplinary treatment approach is essential to maximize outcomes, which includes wound care, risk factor modification, analgesia, and symptomatic management strategies.^1,2,6

Some pharmacologic agents have received noteworthy attention in treating calciphylaxis, including sodium thiosulfate (STS), bisphosphonates, and vitamin K supplementation.¹ The strongest evidence supporting the use of STS comes from 2 trials involving 53 and 27 dialysis patients, with complete remission in 14 (26%) and 14 (52%) patients, respectively.^10,11 However, these trials did not include control groups to compare outcomes, and mortality rates were similarly high among partial responders and nonresponders compared with patients not treated with STS. A 2018 systematic review failed to assess the efficacy of STS alone for the treatment of calciphylaxis but suggested there may be a future role for it, with 251 of 358 patients (70.1%) responding to therapy.¹²

Erythema ab igne is a cutaneous reaction related to long-term heat exposure, often from electronic devices such as laptops, heating pads, space heaters, or hot-water bottles.^13,14 Clinically, this rash appears as an erythematous, purpuric, or hyperpigmented reticular dermatosis that is below the clinical threshold to define a thermal burn.¹³ Lesions often are seen on the anterior thighs or across the abdomen.¹⁵ There usually are no long-term clinical sequelae; however, rare malignant transformation has been documented in cases of atrophy or nonhealing ulceration.¹⁶ Treatment is supportive with removal of the offending agent, but hyperpigmentation may persist for months to years.¹⁴

Livedo reticularis is a cutaneous pattern of mottled violaceous or hyperpigmented changes that often signifies underlying vascular dermal changes.¹⁷ It can be seen in various pathologic states, including vasculitis, autoimmune disease, connective tissue disease, neurologic disease, infection, or malignancy, or it can be drug induced.¹⁸ There are no pathognomonic microscopic changes, as the histology will drastically differ based on the etiology. Workup can be extensive; cues to the underlying pathology should be sought based on the patient’s history and concurrent presenting symptoms. Livedo reticularis is the most common dermatologic finding in patients with antiphospholipid syndrome, and workup should include antiphospholipid antibodies (eg, lupus anticoagulant, anticardiolipin, anti–beta-2-glycoproteins) as well as lupus testing (eg, antinuclear antibodies, anti– double-stranded DNA).¹⁹ Treatment is targeted at the underlying disease process.

Cryoglobulinemia is a disease characterized by abnormal serum immunoglobulins that precipitate at cold temperatures and is further subcategorized by the type of complexes that are deposited.²⁰ Type I represents purely monoclonal cryoglobulins, type III purely polyclonal, and type II a mixed picture. Clinical manifestations arise from excessive deposition of these proteins in the skin, joints, peripheral vasculature, and kidneys leading to purpuric skin lesions, chronic ulceration, arthralgia, and glomerulonephritis. Cutaneous findings may include erythematous to purpuric macular or papular changes with or without the presence of ulceration, infarction, or hemorrhagic crusting.²¹ Systemic disease often underlies a diagnosis, and further investigation for hepatitis C virus, connective tissue disease, and hematologic malignancies should be considered.²⁰ Treatment is targeted at underlying systemic disease, such as antiviral treatment for hepatitis or chemotherapeutic regimens for hematologic disease.²²

Polyarteritis nodosa is a systemic necrotizing vasculitis that typically involves small- to medium-sized arteries. Cutaneous manifestations often include subcutaneous nodules, livedo reticularis, and ulcerations most found on the lower extremities.²³ Systemic symptoms including fever, myalgia, arthralgia, and neuropathy often are present. Characteristic histopathology findings include inflammation and destruction of medium-sized arteries at the junctional zone of the dermis and subcutis along with microaneurysms along the vessels.²⁴ Treatment is based on the severity of disease, with localized cutaneous disease often being controlled with topical steroids and anti-inflammatory agents, while more widespread disease requires immunosuppression with systemic steroids, hydroxychloroquine, azathioprine, methotrexate, mycophenolate mofetil, or intravenous immunoglobulins.²³

The Diagnosis: Calcific Uremic Arteriolopathy

Computed tomography of the abdomen and pelvis with contrast revealed a right complex renal cyst with peripheral calcification; computed tomography of the head without contrast revealed atherosclerotic changes with calcification of the intracranial arteries, vertebral basilar arteries, and bilateral branches of the ophthalmic artery. Histopathology revealed occlusive vasculopathy with epidermal ischemic changes as well as dermal and subcutaneous vascular congestion and small thrombi. Within the subcutis, there were tiny stippled calcium deposits within very small vascular lumina (Figure). The combination of clinical and histological findings was highly suggestive of calcific uremic arteriolopathy, and the patient was transitioned to hemodialysis against a low-calcium bath to avoid hypercalcemia. Unfortunately, she developed complications related to sepsis and experienced worsening mentation. After a discussion with palliative care, the patient was transitioned to comfort measures and discharged home on hospice 1 week after the biopsy at her family’s request.

Calcific uremic arteriolopathy (also known as calciphylaxis) is a rare, life-threatening syndrome of widespread vascular calcification leading to microvascular occlusion within the dermis and subcutaneous tissues.¹ Clinically, it typically manifests as severely painful, purpuric skin lesions that evolve through phases of blistering, ulceration, and ultimately visible skin necrosis.² The pain likely is a consequence of ischemia and nociceptive activation and often may precede any visibly apparent skin lesions.³ Risk factors associated with the development of this condition include female sex; history of diabetes mellitus, obesity, rapid weight loss, or end-stage renal disease; abnormalities in calcium and phosphorus homeostasis; and vitamin K deficiency.^1,3 It is more prevalent in patients on peritoneal dialysis compared to hemodialysis.⁴

Calciphylaxis is diagnosed with combined clinical and histopathological evidence. Laboratory test abnormalities are not specific for disease; therefore, skin biopsy is the standard confirmatory test, though its practice is contentious due to the risk for nonhealing ulceration and increasing risk for infection.¹ Findings suggestive of disease include focal to diffuse calcification (intravascular, extravascular, or perieccrine), superficial fat calcium deposition, mid panniculus calcium deposition, mid panniculus vascular thrombi, and focal to diffuse angioplasia.⁵ The hallmark feature is diffuse calcification of small capillaries in adipose tissue.⁶

The mortality rate associated with this disease is high—a 6-month mortality rate of 27% to 43% has been reported from the time of diagnosis^7-9—which often is related to subsequent superimposed infections patients acquire from necrotic skin tissue.² The disease also carries high morbidity, with patients experiencing frequent hospitalizations related to pain, infections, and nonhealing wounds.⁶ There is no standard treatment, and trials have been limited to small sample sizes. A multidisciplinary treatment approach is essential to maximize outcomes, which includes wound care, risk factor modification, analgesia, and symptomatic management strategies.^1,2,6

Some pharmacologic agents have received noteworthy attention in treating calciphylaxis, including sodium thiosulfate (STS), bisphosphonates, and vitamin K supplementation.¹ The strongest evidence supporting the use of STS comes from 2 trials involving 53 and 27 dialysis patients, with complete remission in 14 (26%) and 14 (52%) patients, respectively.^10,11 However, these trials did not include control groups to compare outcomes, and mortality rates were similarly high among partial responders and nonresponders compared with patients not treated with STS. A 2018 systematic review failed to assess the efficacy of STS alone for the treatment of calciphylaxis but suggested there may be a future role for it, with 251 of 358 patients (70.1%) responding to therapy.¹²

Erythema ab igne is a cutaneous reaction related to long-term heat exposure, often from electronic devices such as laptops, heating pads, space heaters, or hot-water bottles.^13,14 Clinically, this rash appears as an erythematous, purpuric, or hyperpigmented reticular dermatosis that is below the clinical threshold to define a thermal burn.¹³ Lesions often are seen on the anterior thighs or across the abdomen.¹⁵ There usually are no long-term clinical sequelae; however, rare malignant transformation has been documented in cases of atrophy or nonhealing ulceration.¹⁶ Treatment is supportive with removal of the offending agent, but hyperpigmentation may persist for months to years.¹⁴

Livedo reticularis is a cutaneous pattern of mottled violaceous or hyperpigmented changes that often signifies underlying vascular dermal changes.¹⁷ It can be seen in various pathologic states, including vasculitis, autoimmune disease, connective tissue disease, neurologic disease, infection, or malignancy, or it can be drug induced.¹⁸ There are no pathognomonic microscopic changes, as the histology will drastically differ based on the etiology. Workup can be extensive; cues to the underlying pathology should be sought based on the patient’s history and concurrent presenting symptoms. Livedo reticularis is the most common dermatologic finding in patients with antiphospholipid syndrome, and workup should include antiphospholipid antibodies (eg, lupus anticoagulant, anticardiolipin, anti–beta-2-glycoproteins) as well as lupus testing (eg, antinuclear antibodies, anti– double-stranded DNA).¹⁹ Treatment is targeted at the underlying disease process.

Cryoglobulinemia is a disease characterized by abnormal serum immunoglobulins that precipitate at cold temperatures and is further subcategorized by the type of complexes that are deposited.²⁰ Type I represents purely monoclonal cryoglobulins, type III purely polyclonal, and type II a mixed picture. Clinical manifestations arise from excessive deposition of these proteins in the skin, joints, peripheral vasculature, and kidneys leading to purpuric skin lesions, chronic ulceration, arthralgia, and glomerulonephritis. Cutaneous findings may include erythematous to purpuric macular or papular changes with or without the presence of ulceration, infarction, or hemorrhagic crusting.²¹ Systemic disease often underlies a diagnosis, and further investigation for hepatitis C virus, connective tissue disease, and hematologic malignancies should be considered.²⁰ Treatment is targeted at underlying systemic disease, such as antiviral treatment for hepatitis or chemotherapeutic regimens for hematologic disease.²²

Polyarteritis nodosa is a systemic necrotizing vasculitis that typically involves small- to medium-sized arteries. Cutaneous manifestations often include subcutaneous nodules, livedo reticularis, and ulcerations most found on the lower extremities.²³ Systemic symptoms including fever, myalgia, arthralgia, and neuropathy often are present. Characteristic histopathology findings include inflammation and destruction of medium-sized arteries at the junctional zone of the dermis and subcutis along with microaneurysms along the vessels.²⁴ Treatment is based on the severity of disease, with localized cutaneous disease often being controlled with topical steroids and anti-inflammatory agents, while more widespread disease requires immunosuppression with systemic steroids, hydroxychloroquine, azathioprine, methotrexate, mycophenolate mofetil, or intravenous immunoglobulins.²³

To the Editor:

Angioimmunoblastic T-cell lymphoma (AITL) is an uncommon peripheral T-cell lymphoma that accounts for 1% to 2% of all forms of non-Hodgkin lymphoma and usually affects middle-aged individuals.¹ It primarily appears on the skin and mimics an inflammatory dermatosis, leading to diagnostic and therapeutic delays.² No gold-standard treatment has been identified for AITL; the prognosis often remains poor, with a 5-year progression-free survival rate of approximately 25%.³ Because of the rarity of AITL and the unmet need of a standard-of-care treatment regimen, relapsing and remitting disease is common and continues to challenge clinicians.

Methotrexate (MTX), a dihydrofolate reductase inhibitor used to treat many autoimmune diseases, is prescribed at a higher dosage (>500 mg/m²) to manage cancers, including refractory AITL.⁴ In blocking dihydrofolate reductase, MTX reduces the folate pool, with the possible adverse effect of bone marrow suppression. Another important toxic effect is acute kidney injury, which may be due to an overdose of MTX or a patient’s predisposition to chronic kidney failure.⁴

A 50-year-old man was admitted to our inpatient clinic for evaluation of acute oral and genital mucositis. He had a 5-year history of AITL. He was previously treated by hematology with 3 lines of chemotherapy for multiple supradiaphragmatic and subdiaphragmatic localizations of lymphoma, without success. Six days prior to the current presentation, the hematologist started high-dose (3.5 g/m²) intravenous MTX therapy. Five days later, the patient developed transfusion-resistant pancytopenia and fever (maximum body temperature, 102.7°F [39.3°C]).

Physical examination at the current presentation revealed massive necrosis of the lower lip (Figure, A) and partial necrosis of the upper lip. Severe purulent balanoposthitis, causing penile edema and phimosis, complicated the clinical condition. Analysis of a specimen from a cutaneous swab of the penis showed infection with Pseudomonas aeruginosa and Enterococcus faecalis. Considering the clinical presentation and time of onset of signs and symptoms, a diagnosis of acute MTX-induced mucositis was made.

Rescue therapy was started immediately, including high-dose intravenous leucovorin (120 mg 4 times daily), oral sulfamethoxazole-trimethoprim (800 mg/160 mg 3 times daily for 3 days per week), and oral levofloxacin (500 mg/d). After 4 days of treatment, the patient was afebrile. Mucositis of the lips had almost resolved (Figure, B), and balanoposthitis also improved after this rescue therapy. Methotrexate was not resumed because rituximab had been started.

Methotrexate-induced mucositis is a rare severe skin manifestation of MTX toxicity. Prolonged renal toxicity from MTX can predispose a patient to massive myelosuppression, multiorgan failure, and mucositis.⁵ Pancytopenia manifests during the first 10 days of treatment. Because accumulation of MTX is higher in mucosal epithelial cells than in bone marrow stem cells, mucositis usually occurs during the first 7 days of administration, prior to onset of pancytopenia.

Skin involvement usually manifests as oral and genital mucositis due to direct toxicity against epithelial cells, with a pattern of severe keratinocyte necrosis on histopathology, known as MTX-induced epidermal necrosis.⁶ The principal condition in the differential diagnosis is Stevens-Johnson syndrome—including its severe form, toxic epidermal necrolysis—characterized by widespread blistering and more extensive skin detachment caused by an immune-mediated cytotoxic T-cell drug-specific reaction.⁷

 

To prevent MTX toxicity, liver and renal function should be assessed and a complete blood cell count should be performed before starting therapy. These tests should be repeated during treatment to monitor for MTX toxicity.

Leucovorin (folinic acid) counteracts MTX-induced epidermal necrosis by neutralizing the effect of MTX, including antitumoral effectiveness of the drug.⁸ For that reason, leucovorin cannot be started prophylactically.

The main challenges that we encountered in our patient's case were the rarity of reports of AITL in the literature and failure of 3 different lines of chemotherapy previously, which meant that MTX could not possibly be suspended because the drug represented the last therapeutic option. Our case confirms that timely clinical diagnosis and a rapid combined approach consisting of discontinuation of MTX and initiation of leucovorin rescue therapy represents an effective strategy to prevent further toxicity and to alleviate mucositis, even in patients with this rare subset of lymphoma.

To the Editor:

Angioimmunoblastic T-cell lymphoma (AITL) is an uncommon peripheral T-cell lymphoma that accounts for 1% to 2% of all forms of non-Hodgkin lymphoma and usually affects middle-aged individuals.¹ It primarily appears on the skin and mimics an inflammatory dermatosis, leading to diagnostic and therapeutic delays.² No gold-standard treatment has been identified for AITL; the prognosis often remains poor, with a 5-year progression-free survival rate of approximately 25%.³ Because of the rarity of AITL and the unmet need of a standard-of-care treatment regimen, relapsing and remitting disease is common and continues to challenge clinicians.

Methotrexate (MTX), a dihydrofolate reductase inhibitor used to treat many autoimmune diseases, is prescribed at a higher dosage (>500 mg/m²) to manage cancers, including refractory AITL.⁴ In blocking dihydrofolate reductase, MTX reduces the folate pool, with the possible adverse effect of bone marrow suppression. Another important toxic effect is acute kidney injury, which may be due to an overdose of MTX or a patient’s predisposition to chronic kidney failure.⁴

A 50-year-old man was admitted to our inpatient clinic for evaluation of acute oral and genital mucositis. He had a 5-year history of AITL. He was previously treated by hematology with 3 lines of chemotherapy for multiple supradiaphragmatic and subdiaphragmatic localizations of lymphoma, without success. Six days prior to the current presentation, the hematologist started high-dose (3.5 g/m²) intravenous MTX therapy. Five days later, the patient developed transfusion-resistant pancytopenia and fever (maximum body temperature, 102.7°F [39.3°C]).

Physical examination at the current presentation revealed massive necrosis of the lower lip (Figure, A) and partial necrosis of the upper lip. Severe purulent balanoposthitis, causing penile edema and phimosis, complicated the clinical condition. Analysis of a specimen from a cutaneous swab of the penis showed infection with Pseudomonas aeruginosa and Enterococcus faecalis. Considering the clinical presentation and time of onset of signs and symptoms, a diagnosis of acute MTX-induced mucositis was made.

Rescue therapy was started immediately, including high-dose intravenous leucovorin (120 mg 4 times daily), oral sulfamethoxazole-trimethoprim (800 mg/160 mg 3 times daily for 3 days per week), and oral levofloxacin (500 mg/d). After 4 days of treatment, the patient was afebrile. Mucositis of the lips had almost resolved (Figure, B), and balanoposthitis also improved after this rescue therapy. Methotrexate was not resumed because rituximab had been started.

Methotrexate-induced mucositis is a rare severe skin manifestation of MTX toxicity. Prolonged renal toxicity from MTX can predispose a patient to massive myelosuppression, multiorgan failure, and mucositis.⁵ Pancytopenia manifests during the first 10 days of treatment. Because accumulation of MTX is higher in mucosal epithelial cells than in bone marrow stem cells, mucositis usually occurs during the first 7 days of administration, prior to onset of pancytopenia.

Skin involvement usually manifests as oral and genital mucositis due to direct toxicity against epithelial cells, with a pattern of severe keratinocyte necrosis on histopathology, known as MTX-induced epidermal necrosis.⁶ The principal condition in the differential diagnosis is Stevens-Johnson syndrome—including its severe form, toxic epidermal necrolysis—characterized by widespread blistering and more extensive skin detachment caused by an immune-mediated cytotoxic T-cell drug-specific reaction.⁷

 

To prevent MTX toxicity, liver and renal function should be assessed and a complete blood cell count should be performed before starting therapy. These tests should be repeated during treatment to monitor for MTX toxicity.

Leucovorin (folinic acid) counteracts MTX-induced epidermal necrosis by neutralizing the effect of MTX, including antitumoral effectiveness of the drug.⁸ For that reason, leucovorin cannot be started prophylactically.

The main challenges that we encountered in our patient's case were the rarity of reports of AITL in the literature and failure of 3 different lines of chemotherapy previously, which meant that MTX could not possibly be suspended because the drug represented the last therapeutic option. Our case confirms that timely clinical diagnosis and a rapid combined approach consisting of discontinuation of MTX and initiation of leucovorin rescue therapy represents an effective strategy to prevent further toxicity and to alleviate mucositis, even in patients with this rare subset of lymphoma.

To the Editor:

Angioimmunoblastic T-cell lymphoma (AITL) is an uncommon peripheral T-cell lymphoma that accounts for 1% to 2% of all forms of non-Hodgkin lymphoma and usually affects middle-aged individuals.¹ It primarily appears on the skin and mimics an inflammatory dermatosis, leading to diagnostic and therapeutic delays.² No gold-standard treatment has been identified for AITL; the prognosis often remains poor, with a 5-year progression-free survival rate of approximately 25%.³ Because of the rarity of AITL and the unmet need of a standard-of-care treatment regimen, relapsing and remitting disease is common and continues to challenge clinicians.

Methotrexate (MTX), a dihydrofolate reductase inhibitor used to treat many autoimmune diseases, is prescribed at a higher dosage (>500 mg/m²) to manage cancers, including refractory AITL.⁴ In blocking dihydrofolate reductase, MTX reduces the folate pool, with the possible adverse effect of bone marrow suppression. Another important toxic effect is acute kidney injury, which may be due to an overdose of MTX or a patient’s predisposition to chronic kidney failure.⁴

A 50-year-old man was admitted to our inpatient clinic for evaluation of acute oral and genital mucositis. He had a 5-year history of AITL. He was previously treated by hematology with 3 lines of chemotherapy for multiple supradiaphragmatic and subdiaphragmatic localizations of lymphoma, without success. Six days prior to the current presentation, the hematologist started high-dose (3.5 g/m²) intravenous MTX therapy. Five days later, the patient developed transfusion-resistant pancytopenia and fever (maximum body temperature, 102.7°F [39.3°C]).

Physical examination at the current presentation revealed massive necrosis of the lower lip (Figure, A) and partial necrosis of the upper lip. Severe purulent balanoposthitis, causing penile edema and phimosis, complicated the clinical condition. Analysis of a specimen from a cutaneous swab of the penis showed infection with Pseudomonas aeruginosa and Enterococcus faecalis. Considering the clinical presentation and time of onset of signs and symptoms, a diagnosis of acute MTX-induced mucositis was made.

Rescue therapy was started immediately, including high-dose intravenous leucovorin (120 mg 4 times daily), oral sulfamethoxazole-trimethoprim (800 mg/160 mg 3 times daily for 3 days per week), and oral levofloxacin (500 mg/d). After 4 days of treatment, the patient was afebrile. Mucositis of the lips had almost resolved (Figure, B), and balanoposthitis also improved after this rescue therapy. Methotrexate was not resumed because rituximab had been started.

Methotrexate-induced mucositis is a rare severe skin manifestation of MTX toxicity. Prolonged renal toxicity from MTX can predispose a patient to massive myelosuppression, multiorgan failure, and mucositis.⁵ Pancytopenia manifests during the first 10 days of treatment. Because accumulation of MTX is higher in mucosal epithelial cells than in bone marrow stem cells, mucositis usually occurs during the first 7 days of administration, prior to onset of pancytopenia.

Skin involvement usually manifests as oral and genital mucositis due to direct toxicity against epithelial cells, with a pattern of severe keratinocyte necrosis on histopathology, known as MTX-induced epidermal necrosis.⁶ The principal condition in the differential diagnosis is Stevens-Johnson syndrome—including its severe form, toxic epidermal necrolysis—characterized by widespread blistering and more extensive skin detachment caused by an immune-mediated cytotoxic T-cell drug-specific reaction.⁷

 

To prevent MTX toxicity, liver and renal function should be assessed and a complete blood cell count should be performed before starting therapy. These tests should be repeated during treatment to monitor for MTX toxicity.

Leucovorin (folinic acid) counteracts MTX-induced epidermal necrosis by neutralizing the effect of MTX, including antitumoral effectiveness of the drug.⁸ For that reason, leucovorin cannot be started prophylactically.

The main challenges that we encountered in our patient's case were the rarity of reports of AITL in the literature and failure of 3 different lines of chemotherapy previously, which meant that MTX could not possibly be suspended because the drug represented the last therapeutic option. Our case confirms that timely clinical diagnosis and a rapid combined approach consisting of discontinuation of MTX and initiation of leucovorin rescue therapy represents an effective strategy to prevent further toxicity and to alleviate mucositis, even in patients with this rare subset of lymphoma.

To the Editor:

Phototherapy regularly is utilized in the outpatient setting to address various skin pathologies, including atopic dermatitis, psoriasis, pruritus, vitiligo, and mycosis fungoides.^1,2 Phototherapy is broadly defined by the measured administration of nonionizing radiation within the UV range including wavelengths within the UVA (eg, psoralen sensitizer plus UVA-1) and UVB (eg, broadband UVB, narrowband UVB) spectrums.^1,3 Generally, the mechanism of action is derived from effects on inflammatory components of cutaneous disorders and the induction of apoptosis, both precipitating numerous downstream events.⁴

From 2015 to 2018, there were more than 1.3 million outpatient phototherapy visits in the United States, with the most common procedural indications being dermatitis not otherwise specified, atopic dermatitis, and pruritus.⁵ From 2000 to 2015, the quantity of phototherapy services billed to Medicare trended upwards by an average of 5% per year, increasing from 334,670 in the year 2000 to 692,093 in 2015.⁶ Therefore, an illustration of associated costs would be beneficial. Additionally, because total cost and physician reimbursement fluctuate from year to year, studies demonstrating overall trends can inform both US policymakers and physicians. There is a paucity of research on geographical trends for procedural reimbursements in dermatology for phototherapy. Understanding geographic trends of reimbursement could duly serve to optimize dermatologist practice patterns involving access to viable and quality care for patients seeking treatment as well as draw health policymakers’ attention to striking adjustments in physician fees. Therefore, in this study we aimed to illustrate the most recent regional payment trends in phototherapy procedures for Medicare B patients.

We queried the Centers for Medicare & Medicaid Services Medicare Physician Fee Schedule (MPFS) database (https://www.cms.gov/medicare/payment/fee-schedules/physician/lookup-tool) for the years 2010 to 2023 for Current Procedural Terminology (CPT) codes common to phototherapy procedures: actinotherapy (96900); photochemotherapy by Goeckerman treatment or using petrolatum and UVB (96910); photochemotherapy using psoralen plus UVA (96912); and photochemotherapy of severe dermatoses requiring a minimum of 4 hours of care under direct physician supervision (96913). Nonfacility prices for these procedures were analyzed. For 2010, due to midyear alterations to Medicare reimbursement (owed to bills HR 3962 and HR 4872), the mean price data of MPFS files 2010A and 2010B were used. All dollar values were converted to January 2023 US dollars using corresponding consumer price index inflation data. The Medicare Administrative Contractors were used to group state pricing information by region in accordance with established US Census Bureau subdivisions (https://www.census.gov/programs-surveys/economic-census/guidance-geographies/levels.html). Weighted percentage change in reimbursement rate was calculated using physician (MD or DO) utilization (procedure volume) data available in the 2020 Physician and Other Practitioners Public Use File (https://data.cms.gov/provider-summary-by-type-of-service/medicare-physician-other-practitioners/medicare-physician-other-practitioners-by-provider-and-service). All descriptive statistics and visualization were generated using R software (v4.2.2)(R Development Core Team).

Table 1 provides physician utilization data and the corresponding number of Part B beneficiaries for phototherapy procedures in 2020. There were 65,045 services of actinotherapy provided to a total of 6855 unique Part B beneficiaries, 173,979 services of photochemotherapy by Goeckerman treatment or using petrolatum and UVB provided to 13,122 unique Part B beneficiaries, 2524 services of photochemotherapy using psoralen plus UVA provided to a total of 357 unique Part B beneficiaries, and 37 services of photochemotherapy of severe dermatoses requiring a minimum of 4 hours of care under direct physician supervision provided to a total of 27 unique Part B beneficiaries.

On average (unweighted), phototherapy reimbursement rates in the North increased by 0.68% between 2010 and 2023 (Table 2). After weighting for 2020 physician utilization, the average change in reimbursement rate was +19.37%. During this time period, CPT code 96910 reported the greatest adjusted increase in reimbursement (+31.45%)($98.12 to $128.98; compound annual growth rate [CAGR], +0.0213), and CPT code 96912 reported the greatest adjusted decrease in reimbursement (−12.76%)($126.09 to $109.97; CAGR, −0.0105). For CPT code 96900, the reported adjusted decrease in reimbursement was −11.68% ($30.21 to $26.68; CAGR, −0.0095), and for CPT code 96913, the reported adjusted decrease in reimbursement was −4.27% ($174.03 to $166.60; CAGR, −0.0034).

On average (unweighted), phototherapy reimbursement rates in the Midwest increased by 8.40% between 2010 and 2023 (Table 3). After weighting for 2020 physician utilization, the average change in reimbursement rate was +28.53%. During this time period, CPT code 96910 reported the greatest adjusted change in reimbursement (+41.48%)($80.42 to $113.78; CAGR, +0.0270), and CPT code 96912 reported the greatest adjusted decrease in reimbursement (−6.14%)($103.28 to $97.03; CAGR, −0.0049). For CPT code 96900, the reported adjusted decrease in reimbursement was −4.73% ($24.69 to $23.52; CAGR, −0.0037), and for CPT code 96913, the reported adjusted increase in reimbursement was +2.99% ($142.72 to $146.99; CAGR, +0.0023).

On average (unweighted), phototherapy reimbursement rates in the South decreased by 2.62% between 2010 and 2023 (Table 4). After weighting for 2020 physician utilization, the average change in reimbursement rate was +15.41%. During this time period, CPT code 96910 reported the greatest adjusted change in reimbursement (+27.26%)($90.40 to $115.04 USD; CAGR, +0.0187), and CPT code 96912 reported the greatest adjusted decrease in reimbursement (−15.50%)($116.08 to $98.09; CAGR, −0.0129). For CPT code 96900, the reported adjusted decrease in reimbursement was −15.06% ($28.02 to $23.80; CAGR, −0.0125), and for CPT code 96913, the reported adjusted decrease in reimbursement was −7.19% ($160.11 to $148.61; CAGR, −0.0057).

 

On average (unweighted), phototherapy reimbursement rates in the West increased by 27.53% between 2010 and 2023 (Table 5). After weighting for 2020 physician utilization, the average change in reimbursement rate was +51.16%. Reimbursement for all analyzed procedures increased in the western United States. During this time period, CPT code 96910 reported the greatest adjusted increase in reimbursement (+66.56%)($80.84 to $134.65; CAGR, +0.0400), and CPT code 96912 reported the lowest adjusted increase in reimbursement (+10.64%)($103.88 to $114.93; CAGR, +0.0078). For CPT code 96900, the reported adjusted increase in reimbursement was 11.54% ($24.88 to $27.75; CAGR, +0.0084), and for CPT code 96913, the reported adjusted increase in reimbursement was 21.38% ($143.39 to $174.04; CAGR, +0.0150).

In this study evaluating geographical payment trends for phototherapy from 2010 to 2023, we demonstrated regional inconsistency in mean inflation-adjusted Medicare reimbursement rates. We found that all phototherapy procedures had increased reimbursement in the western United States, whereas all other regions reported cuts in reimbursement rates for at least half of the analyzed procedures. After adjusting for procedure utilization by physicians, weighted mean reimbursement for phototherapy increased in all US regions.

In a cross-sectional study that explored trends in the geographic distribution of dermatologists from 2012 to 2017, dermatologists in the northeastern and western United States were more likely to be located in higher-income zip codes, whereas dermatologists in the southern United States were more likely to be located in lower-income zip codes,⁷ suggesting that payment rate changes are not concordant with cost of living. Additionally, Lauck and colleagues⁸ observed that 75% of the top 20 most common procedures performed by dermatologists had decreased reimbursement (mean change, −10.8%) from 2011 to 2021. Other studies on Medicare reimbursement trends over the last 2 decades have reported major decreases within other specialties, suggesting that declining Medicare reimbursements are not unique to dermatology.^9,10 It is critical to monitor these developments, as the Centers for Medicare & Medicaid Services emphasized health care policy changes aimed at increasing reimbursements for evaluation and management services with compensatory payment cuts in billing for procedural services.¹¹

Mazmudar et al¹² previously reported a mean reimbursement decrease of −6.6% for laser/phototherapy procedures between 2007 and 2021, but these data did not include the heavily utilized Goeckerman treatment. Changes in reimbursement pose major ramifications for dermatologists—for practice size, scope, and longevity—as rates influence changes in commercial insurance reimbursements.¹³ Medicare plays a major role in the US health care system as the second largest expenditure¹⁴; indeed, between 2000 and 2015, Part B billing volume for phototherapy procedures increased 5% annually. However, phototherapy remains inaccessible in many locations due to unequal regional distribution of phototherapy clinics.⁶ Moreover, home phototherapy units are not yet widely utilized because of safety and efficacy concerns, lack of physician oversight, and difficulty obtaining insurance coverage.¹⁵ Acknowledgment and consideration of these geographical trends may persuasively allow policymakers, hospitals, and physicians to facilitate cost-effective phototherapy reimbursements that ensure continued access to quality and sustainable dermatologic care in the United States that tailor to regional needs.

In sum, this analysis reveals regional trends in Part B physician reimbursement for phototherapy procedures, with all US regions reporting a mean increase in phototherapy reimbursement after adjusting for utilization, albeit to varying degrees. Mean reimbursement for photochemotherapy by Goeckerman treatment or using petrolatum and UVB increased most among phototherapy procedures. Mean reimbursement for both actinotherapy and photochemotherapy using psoralen plus UVA decreased in all regions except the western United States.

Limitations include the restriction to Part B MPFS and the reliance on single-year (2020) physician utilization data to compute weighted changes in average reimbursement across a multiyear range, effectively restricting sweeping conclusions. Still, this study puts forth actionable insights for dermatologists and policymakers alike to appreciate and consider.

To the Editor:

Phototherapy regularly is utilized in the outpatient setting to address various skin pathologies, including atopic dermatitis, psoriasis, pruritus, vitiligo, and mycosis fungoides.^1,2 Phototherapy is broadly defined by the measured administration of nonionizing radiation within the UV range including wavelengths within the UVA (eg, psoralen sensitizer plus UVA-1) and UVB (eg, broadband UVB, narrowband UVB) spectrums.^1,3 Generally, the mechanism of action is derived from effects on inflammatory components of cutaneous disorders and the induction of apoptosis, both precipitating numerous downstream events.⁴

From 2015 to 2018, there were more than 1.3 million outpatient phototherapy visits in the United States, with the most common procedural indications being dermatitis not otherwise specified, atopic dermatitis, and pruritus.⁵ From 2000 to 2015, the quantity of phototherapy services billed to Medicare trended upwards by an average of 5% per year, increasing from 334,670 in the year 2000 to 692,093 in 2015.⁶ Therefore, an illustration of associated costs would be beneficial. Additionally, because total cost and physician reimbursement fluctuate from year to year, studies demonstrating overall trends can inform both US policymakers and physicians. There is a paucity of research on geographical trends for procedural reimbursements in dermatology for phototherapy. Understanding geographic trends of reimbursement could duly serve to optimize dermatologist practice patterns involving access to viable and quality care for patients seeking treatment as well as draw health policymakers’ attention to striking adjustments in physician fees. Therefore, in this study we aimed to illustrate the most recent regional payment trends in phototherapy procedures for Medicare B patients.

We queried the Centers for Medicare & Medicaid Services Medicare Physician Fee Schedule (MPFS) database (https://www.cms.gov/medicare/payment/fee-schedules/physician/lookup-tool) for the years 2010 to 2023 for Current Procedural Terminology (CPT) codes common to phototherapy procedures: actinotherapy (96900); photochemotherapy by Goeckerman treatment or using petrolatum and UVB (96910); photochemotherapy using psoralen plus UVA (96912); and photochemotherapy of severe dermatoses requiring a minimum of 4 hours of care under direct physician supervision (96913). Nonfacility prices for these procedures were analyzed. For 2010, due to midyear alterations to Medicare reimbursement (owed to bills HR 3962 and HR 4872), the mean price data of MPFS files 2010A and 2010B were used. All dollar values were converted to January 2023 US dollars using corresponding consumer price index inflation data. The Medicare Administrative Contractors were used to group state pricing information by region in accordance with established US Census Bureau subdivisions (https://www.census.gov/programs-surveys/economic-census/guidance-geographies/levels.html). Weighted percentage change in reimbursement rate was calculated using physician (MD or DO) utilization (procedure volume) data available in the 2020 Physician and Other Practitioners Public Use File (https://data.cms.gov/provider-summary-by-type-of-service/medicare-physician-other-practitioners/medicare-physician-other-practitioners-by-provider-and-service). All descriptive statistics and visualization were generated using R software (v4.2.2)(R Development Core Team).

Table 1 provides physician utilization data and the corresponding number of Part B beneficiaries for phototherapy procedures in 2020. There were 65,045 services of actinotherapy provided to a total of 6855 unique Part B beneficiaries, 173,979 services of photochemotherapy by Goeckerman treatment or using petrolatum and UVB provided to 13,122 unique Part B beneficiaries, 2524 services of photochemotherapy using psoralen plus UVA provided to a total of 357 unique Part B beneficiaries, and 37 services of photochemotherapy of severe dermatoses requiring a minimum of 4 hours of care under direct physician supervision provided to a total of 27 unique Part B beneficiaries.

On average (unweighted), phototherapy reimbursement rates in the North increased by 0.68% between 2010 and 2023 (Table 2). After weighting for 2020 physician utilization, the average change in reimbursement rate was +19.37%. During this time period, CPT code 96910 reported the greatest adjusted increase in reimbursement (+31.45%)($98.12 to $128.98; compound annual growth rate [CAGR], +0.0213), and CPT code 96912 reported the greatest adjusted decrease in reimbursement (−12.76%)($126.09 to $109.97; CAGR, −0.0105). For CPT code 96900, the reported adjusted decrease in reimbursement was −11.68% ($30.21 to $26.68; CAGR, −0.0095), and for CPT code 96913, the reported adjusted decrease in reimbursement was −4.27% ($174.03 to $166.60; CAGR, −0.0034).

On average (unweighted), phototherapy reimbursement rates in the Midwest increased by 8.40% between 2010 and 2023 (Table 3). After weighting for 2020 physician utilization, the average change in reimbursement rate was +28.53%. During this time period, CPT code 96910 reported the greatest adjusted change in reimbursement (+41.48%)($80.42 to $113.78; CAGR, +0.0270), and CPT code 96912 reported the greatest adjusted decrease in reimbursement (−6.14%)($103.28 to $97.03; CAGR, −0.0049). For CPT code 96900, the reported adjusted decrease in reimbursement was −4.73% ($24.69 to $23.52; CAGR, −0.0037), and for CPT code 96913, the reported adjusted increase in reimbursement was +2.99% ($142.72 to $146.99; CAGR, +0.0023).

On average (unweighted), phototherapy reimbursement rates in the South decreased by 2.62% between 2010 and 2023 (Table 4). After weighting for 2020 physician utilization, the average change in reimbursement rate was +15.41%. During this time period, CPT code 96910 reported the greatest adjusted change in reimbursement (+27.26%)($90.40 to $115.04 USD; CAGR, +0.0187), and CPT code 96912 reported the greatest adjusted decrease in reimbursement (−15.50%)($116.08 to $98.09; CAGR, −0.0129). For CPT code 96900, the reported adjusted decrease in reimbursement was −15.06% ($28.02 to $23.80; CAGR, −0.0125), and for CPT code 96913, the reported adjusted decrease in reimbursement was −7.19% ($160.11 to $148.61; CAGR, −0.0057).

 

On average (unweighted), phototherapy reimbursement rates in the West increased by 27.53% between 2010 and 2023 (Table 5). After weighting for 2020 physician utilization, the average change in reimbursement rate was +51.16%. Reimbursement for all analyzed procedures increased in the western United States. During this time period, CPT code 96910 reported the greatest adjusted increase in reimbursement (+66.56%)($80.84 to $134.65; CAGR, +0.0400), and CPT code 96912 reported the lowest adjusted increase in reimbursement (+10.64%)($103.88 to $114.93; CAGR, +0.0078). For CPT code 96900, the reported adjusted increase in reimbursement was 11.54% ($24.88 to $27.75; CAGR, +0.0084), and for CPT code 96913, the reported adjusted increase in reimbursement was 21.38% ($143.39 to $174.04; CAGR, +0.0150).

In this study evaluating geographical payment trends for phototherapy from 2010 to 2023, we demonstrated regional inconsistency in mean inflation-adjusted Medicare reimbursement rates. We found that all phototherapy procedures had increased reimbursement in the western United States, whereas all other regions reported cuts in reimbursement rates for at least half of the analyzed procedures. After adjusting for procedure utilization by physicians, weighted mean reimbursement for phototherapy increased in all US regions.

In a cross-sectional study that explored trends in the geographic distribution of dermatologists from 2012 to 2017, dermatologists in the northeastern and western United States were more likely to be located in higher-income zip codes, whereas dermatologists in the southern United States were more likely to be located in lower-income zip codes,⁷ suggesting that payment rate changes are not concordant with cost of living. Additionally, Lauck and colleagues⁸ observed that 75% of the top 20 most common procedures performed by dermatologists had decreased reimbursement (mean change, −10.8%) from 2011 to 2021. Other studies on Medicare reimbursement trends over the last 2 decades have reported major decreases within other specialties, suggesting that declining Medicare reimbursements are not unique to dermatology.^9,10 It is critical to monitor these developments, as the Centers for Medicare & Medicaid Services emphasized health care policy changes aimed at increasing reimbursements for evaluation and management services with compensatory payment cuts in billing for procedural services.¹¹

Mazmudar et al¹² previously reported a mean reimbursement decrease of −6.6% for laser/phototherapy procedures between 2007 and 2021, but these data did not include the heavily utilized Goeckerman treatment. Changes in reimbursement pose major ramifications for dermatologists—for practice size, scope, and longevity—as rates influence changes in commercial insurance reimbursements.¹³ Medicare plays a major role in the US health care system as the second largest expenditure¹⁴; indeed, between 2000 and 2015, Part B billing volume for phototherapy procedures increased 5% annually. However, phototherapy remains inaccessible in many locations due to unequal regional distribution of phototherapy clinics.⁶ Moreover, home phototherapy units are not yet widely utilized because of safety and efficacy concerns, lack of physician oversight, and difficulty obtaining insurance coverage.¹⁵ Acknowledgment and consideration of these geographical trends may persuasively allow policymakers, hospitals, and physicians to facilitate cost-effective phototherapy reimbursements that ensure continued access to quality and sustainable dermatologic care in the United States that tailor to regional needs.

In sum, this analysis reveals regional trends in Part B physician reimbursement for phototherapy procedures, with all US regions reporting a mean increase in phototherapy reimbursement after adjusting for utilization, albeit to varying degrees. Mean reimbursement for photochemotherapy by Goeckerman treatment or using petrolatum and UVB increased most among phototherapy procedures. Mean reimbursement for both actinotherapy and photochemotherapy using psoralen plus UVA decreased in all regions except the western United States.

Limitations include the restriction to Part B MPFS and the reliance on single-year (2020) physician utilization data to compute weighted changes in average reimbursement across a multiyear range, effectively restricting sweeping conclusions. Still, this study puts forth actionable insights for dermatologists and policymakers alike to appreciate and consider.

To the Editor:

Phototherapy regularly is utilized in the outpatient setting to address various skin pathologies, including atopic dermatitis, psoriasis, pruritus, vitiligo, and mycosis fungoides.^1,2 Phototherapy is broadly defined by the measured administration of nonionizing radiation within the UV range including wavelengths within the UVA (eg, psoralen sensitizer plus UVA-1) and UVB (eg, broadband UVB, narrowband UVB) spectrums.^1,3 Generally, the mechanism of action is derived from effects on inflammatory components of cutaneous disorders and the induction of apoptosis, both precipitating numerous downstream events.⁴

From 2015 to 2018, there were more than 1.3 million outpatient phototherapy visits in the United States, with the most common procedural indications being dermatitis not otherwise specified, atopic dermatitis, and pruritus.⁵ From 2000 to 2015, the quantity of phototherapy services billed to Medicare trended upwards by an average of 5% per year, increasing from 334,670 in the year 2000 to 692,093 in 2015.⁶ Therefore, an illustration of associated costs would be beneficial. Additionally, because total cost and physician reimbursement fluctuate from year to year, studies demonstrating overall trends can inform both US policymakers and physicians. There is a paucity of research on geographical trends for procedural reimbursements in dermatology for phototherapy. Understanding geographic trends of reimbursement could duly serve to optimize dermatologist practice patterns involving access to viable and quality care for patients seeking treatment as well as draw health policymakers’ attention to striking adjustments in physician fees. Therefore, in this study we aimed to illustrate the most recent regional payment trends in phototherapy procedures for Medicare B patients.

We queried the Centers for Medicare & Medicaid Services Medicare Physician Fee Schedule (MPFS) database (https://www.cms.gov/medicare/payment/fee-schedules/physician/lookup-tool) for the years 2010 to 2023 for Current Procedural Terminology (CPT) codes common to phototherapy procedures: actinotherapy (96900); photochemotherapy by Goeckerman treatment or using petrolatum and UVB (96910); photochemotherapy using psoralen plus UVA (96912); and photochemotherapy of severe dermatoses requiring a minimum of 4 hours of care under direct physician supervision (96913). Nonfacility prices for these procedures were analyzed. For 2010, due to midyear alterations to Medicare reimbursement (owed to bills HR 3962 and HR 4872), the mean price data of MPFS files 2010A and 2010B were used. All dollar values were converted to January 2023 US dollars using corresponding consumer price index inflation data. The Medicare Administrative Contractors were used to group state pricing information by region in accordance with established US Census Bureau subdivisions (https://www.census.gov/programs-surveys/economic-census/guidance-geographies/levels.html). Weighted percentage change in reimbursement rate was calculated using physician (MD or DO) utilization (procedure volume) data available in the 2020 Physician and Other Practitioners Public Use File (https://data.cms.gov/provider-summary-by-type-of-service/medicare-physician-other-practitioners/medicare-physician-other-practitioners-by-provider-and-service). All descriptive statistics and visualization were generated using R software (v4.2.2)(R Development Core Team).

Table 1 provides physician utilization data and the corresponding number of Part B beneficiaries for phototherapy procedures in 2020. There were 65,045 services of actinotherapy provided to a total of 6855 unique Part B beneficiaries, 173,979 services of photochemotherapy by Goeckerman treatment or using petrolatum and UVB provided to 13,122 unique Part B beneficiaries, 2524 services of photochemotherapy using psoralen plus UVA provided to a total of 357 unique Part B beneficiaries, and 37 services of photochemotherapy of severe dermatoses requiring a minimum of 4 hours of care under direct physician supervision provided to a total of 27 unique Part B beneficiaries.

On average (unweighted), phototherapy reimbursement rates in the North increased by 0.68% between 2010 and 2023 (Table 2). After weighting for 2020 physician utilization, the average change in reimbursement rate was +19.37%. During this time period, CPT code 96910 reported the greatest adjusted increase in reimbursement (+31.45%)($98.12 to $128.98; compound annual growth rate [CAGR], +0.0213), and CPT code 96912 reported the greatest adjusted decrease in reimbursement (−12.76%)($126.09 to $109.97; CAGR, −0.0105). For CPT code 96900, the reported adjusted decrease in reimbursement was −11.68% ($30.21 to $26.68; CAGR, −0.0095), and for CPT code 96913, the reported adjusted decrease in reimbursement was −4.27% ($174.03 to $166.60; CAGR, −0.0034).

On average (unweighted), phototherapy reimbursement rates in the Midwest increased by 8.40% between 2010 and 2023 (Table 3). After weighting for 2020 physician utilization, the average change in reimbursement rate was +28.53%. During this time period, CPT code 96910 reported the greatest adjusted change in reimbursement (+41.48%)($80.42 to $113.78; CAGR, +0.0270), and CPT code 96912 reported the greatest adjusted decrease in reimbursement (−6.14%)($103.28 to $97.03; CAGR, −0.0049). For CPT code 96900, the reported adjusted decrease in reimbursement was −4.73% ($24.69 to $23.52; CAGR, −0.0037), and for CPT code 96913, the reported adjusted increase in reimbursement was +2.99% ($142.72 to $146.99; CAGR, +0.0023).

On average (unweighted), phototherapy reimbursement rates in the South decreased by 2.62% between 2010 and 2023 (Table 4). After weighting for 2020 physician utilization, the average change in reimbursement rate was +15.41%. During this time period, CPT code 96910 reported the greatest adjusted change in reimbursement (+27.26%)($90.40 to $115.04 USD; CAGR, +0.0187), and CPT code 96912 reported the greatest adjusted decrease in reimbursement (−15.50%)($116.08 to $98.09; CAGR, −0.0129). For CPT code 96900, the reported adjusted decrease in reimbursement was −15.06% ($28.02 to $23.80; CAGR, −0.0125), and for CPT code 96913, the reported adjusted decrease in reimbursement was −7.19% ($160.11 to $148.61; CAGR, −0.0057).

 

On average (unweighted), phototherapy reimbursement rates in the West increased by 27.53% between 2010 and 2023 (Table 5). After weighting for 2020 physician utilization, the average change in reimbursement rate was +51.16%. Reimbursement for all analyzed procedures increased in the western United States. During this time period, CPT code 96910 reported the greatest adjusted increase in reimbursement (+66.56%)($80.84 to $134.65; CAGR, +0.0400), and CPT code 96912 reported the lowest adjusted increase in reimbursement (+10.64%)($103.88 to $114.93; CAGR, +0.0078). For CPT code 96900, the reported adjusted increase in reimbursement was 11.54% ($24.88 to $27.75; CAGR, +0.0084), and for CPT code 96913, the reported adjusted increase in reimbursement was 21.38% ($143.39 to $174.04; CAGR, +0.0150).

In this study evaluating geographical payment trends for phototherapy from 2010 to 2023, we demonstrated regional inconsistency in mean inflation-adjusted Medicare reimbursement rates. We found that all phototherapy procedures had increased reimbursement in the western United States, whereas all other regions reported cuts in reimbursement rates for at least half of the analyzed procedures. After adjusting for procedure utilization by physicians, weighted mean reimbursement for phototherapy increased in all US regions.

In a cross-sectional study that explored trends in the geographic distribution of dermatologists from 2012 to 2017, dermatologists in the northeastern and western United States were more likely to be located in higher-income zip codes, whereas dermatologists in the southern United States were more likely to be located in lower-income zip codes,⁷ suggesting that payment rate changes are not concordant with cost of living. Additionally, Lauck and colleagues⁸ observed that 75% of the top 20 most common procedures performed by dermatologists had decreased reimbursement (mean change, −10.8%) from 2011 to 2021. Other studies on Medicare reimbursement trends over the last 2 decades have reported major decreases within other specialties, suggesting that declining Medicare reimbursements are not unique to dermatology.^9,10 It is critical to monitor these developments, as the Centers for Medicare & Medicaid Services emphasized health care policy changes aimed at increasing reimbursements for evaluation and management services with compensatory payment cuts in billing for procedural services.¹¹

Mazmudar et al¹² previously reported a mean reimbursement decrease of −6.6% for laser/phototherapy procedures between 2007 and 2021, but these data did not include the heavily utilized Goeckerman treatment. Changes in reimbursement pose major ramifications for dermatologists—for practice size, scope, and longevity—as rates influence changes in commercial insurance reimbursements.¹³ Medicare plays a major role in the US health care system as the second largest expenditure¹⁴; indeed, between 2000 and 2015, Part B billing volume for phototherapy procedures increased 5% annually. However, phototherapy remains inaccessible in many locations due to unequal regional distribution of phototherapy clinics.⁶ Moreover, home phototherapy units are not yet widely utilized because of safety and efficacy concerns, lack of physician oversight, and difficulty obtaining insurance coverage.¹⁵ Acknowledgment and consideration of these geographical trends may persuasively allow policymakers, hospitals, and physicians to facilitate cost-effective phototherapy reimbursements that ensure continued access to quality and sustainable dermatologic care in the United States that tailor to regional needs.

In sum, this analysis reveals regional trends in Part B physician reimbursement for phototherapy procedures, with all US regions reporting a mean increase in phototherapy reimbursement after adjusting for utilization, albeit to varying degrees. Mean reimbursement for photochemotherapy by Goeckerman treatment or using petrolatum and UVB increased most among phototherapy procedures. Mean reimbursement for both actinotherapy and photochemotherapy using psoralen plus UVA decreased in all regions except the western United States.

Limitations include the restriction to Part B MPFS and the reliance on single-year (2020) physician utilization data to compute weighted changes in average reimbursement across a multiyear range, effectively restricting sweeping conclusions. Still, this study puts forth actionable insights for dermatologists and policymakers alike to appreciate and consider.

To the Editor:

A 14-year-old Black adolescent girl presented with episodic, painful, edematous plaques that occurred symmetrically on the arms and legs of 5 years’ duration. The plaques evolved into hyperpigmented patches within 24 to 48 hours before eventually resolving. Fatigue, headache, arthralgias of the arms and legs, chest pain, abdominal pain, nausea, and vomiting variably accompanied these episodes.

Prior to visiting our clinic, the patient had been seen by numerous specialists. A review of her medical records revealed an initial diagnosis of Henoch-Schönlein purpura (HSP), then urticarial vasculitis. She had been treated with antihistamines, topical and systemic steroids, hydroxychloroquine, mycophenolate mofetil, dapsone, azathioprine, and gabapentin. All treatments were ineffectual. She underwent extensive diagnostic testing and imaging, which were normal or noncontributory, including type I allergy testing; multiple exhaustive batteries of hematologic testing; and computed tomography/magnetic resonance imaging/magnetic resonance angiography of the brain, chest, abdomen, and pelvic region. Biopsies from symptomatic segments of the gastrointestinal tract were normal.

Chronic treatment with systemic steroids over 9 months resulted in gastritis and an episode of hematemesis requiring emergent hospitalization. A lengthy multidisciplinary evaluation was conducted at the patient’s local community hospital; the team concluded that she had an urticarial-type rash with accompanying symptoms that did not have an autoimmune, rheumatologic, or inflammatory basis.

The patient’s medical history was remarkable for recent-onset panic attacks. Her family medical history was noncontributory. Physical examination revealed multiple violaceous hyperpigmented patches diffusely located on the proximal upper arms (Figure 1). There were no additional findings on physical examination.

Punch biopsies were performed on lesional areas of the arm. Histopathology indicated a mild superficial perivascular dermal mixed infiltrate and extravasated erythrocytes (Figure 2). Direct immunofluorescence (DIF) testing was negative for vasculitis. Immunohistochemical stains for CD117 and tryptase demonstrated a slight increase in the number of dermal mast cells; however, the increase was not sufficient to diagnose cutaneous mastocytosis, which was in the differential. We proposed a diagnosis of psychogenic purpura (PP)(also known as Gardner-Diamond syndrome). She was treated with gabapentin, a selective serotonin reuptake inhibitor, and cognitive therapy. Unfortunately, after starting therapy the patient was lost to follow-up.

Psychogenic purpura is a rare vasculopathy of unknown etiology that may be a special form of factitious disorder.^1,2 In one study, PP occurred predominantly in females aged 15 to 66 years, with a median onset age of 33 years.³ A prodrome of localized itching, burning, and/or pain precedes the development of edematous plaques. The plaques evolve into painful ecchymoses within 1 to 2 days and resolve in 10 days or fewer without treatment. Lesions most commonly occur on the extremities but may occur anywhere on the body. The most common associated finding is an underlying depressive disorder. Episodes may be accompanied by headache, dizziness, fatigue, fever, arthralgia, nausea, vomiting, abdominal pain, menstrual irregularities, myalgia, and urologic conditions.

In 1955, Gardner and Diamond⁴ described the first cases of PP in 4 female patients at Peter Bent Brigham Hospital in Boston, Massachusetts. The investigators were able to replicate the painful ecchymoses with intradermal injection of the patient’s own erythrocytes into the skin. They proposed that the underlying pathogenesis involved autosensitization to erythrocyte stroma.⁴ Since then, others have suggested that the pathogenesis may include autosensitization to erythrocyte phosphatidylserine, tonus dysregulation of venous capillaries, abnormal endothelial fibrin synthesis, and capillary wall instability.^5-7 

 

Histopathology typically reveals superficial and deep perivascular inflammation with extravasated erythrocytes. Direct immunofluorescence is negative for vasculitis.⁸ Diagnostics and laboratory findings for underlying systemic illness are negative or noncontributory. Cutaneous injection of 1 mL of the patient’s own washed erythrocytes may result in the formation of the characteristic painful plaques within 24 hours; however, this test is limited by lack of standardization and low sensitivity.³

Psychogenic purpura may share clinical features with cutaneous small vessel vasculitis, such as HSP or urticarial vasculitis. Some of the findings that our patient was experiencing, including purpura, arthralgia, and abdominal pain, are associated with HSP. However, HSP typically is self-limiting and classically features palpable purpura distributed across the lower extremities and buttocks. Histopathology demonstrates the classic findings of leukocytoclastic vasculitis; DIF typically is positive for perivascular IgA and C3 deposition. Increased serum IgA may be present.⁹ Urticarial vasculitis appears as erythematous indurated wheals that favor a proximal extremity and truncal distribution. They characteristically last longer than 24 hours, are frequently associated with nonprodromal pain or burning, and resolve with hyperpigmentation. Arthralgia and gastrointestinal, renal, pulmonary, cardiac, and neurologic symptoms may be present, especially in patients with low complement levels.¹⁰ Skin biopsy demonstrates leukocytoclasia that must be accompanied by vessel wall necrosis. Fibrinoid deposition, erythrocyte extravasation, or perivascular inflammation may be present. In 70% of cases revealing perivascular immunoglobulin, C3, and fibrinogen deposition, DIF is positive. Serum C1q autoantibody may be associated with the hypocomplementemic form.¹⁰

The classic histopathologic findings in leukocytoclastic vasculitis include transmural neutrophilic infiltration of the walls of small vessels, fibrinoid necrosis of vessel walls, leukocytoclasia, extravasated erythrocytes, and signs of endothelial cell damage.⁹ A prior punch biopsy in this patient demonstrated rare neutrophilic nuclear debris within the vessel walls without fibrin deposition. Although the presence of nuclear debris and extravasated erythrocytes could be compatible with a manifestation of urticarial vasculitis, the lack of direct evidence of vessel wall necrosis combined with subsequent biopsies unequivocally ruled out cutaneous small vessel vasculitis in our patient.

Psychogenic purpura has been reported to occur frequently in the background of psycho-emotional distress. In 1989, Ratnoff¹¹ noted that many of the patients he was treating at the University Hospitals of Cleveland, Ohio, had a depressive syndrome. A review of patients treated at the Mayo Clinic in Rochester, Minnesota, illustrated concomitant psychiatric illnesses in 41 of 76 (54%) patients treated for PP, most commonly depressive, personality, and anxiety disorders.³

There is no consensus on therapy for PP. Treatment is based on providing symptomatic relief and relieving underlying psychiatric distress. Block et al¹² found the use of selective serotonin reuptake inhibitors, tricyclic antidepressants, and psychotherapy to be successful in improving symptoms and reducing lesions at follow-up visits.

To the Editor:

A 14-year-old Black adolescent girl presented with episodic, painful, edematous plaques that occurred symmetrically on the arms and legs of 5 years’ duration. The plaques evolved into hyperpigmented patches within 24 to 48 hours before eventually resolving. Fatigue, headache, arthralgias of the arms and legs, chest pain, abdominal pain, nausea, and vomiting variably accompanied these episodes.

Prior to visiting our clinic, the patient had been seen by numerous specialists. A review of her medical records revealed an initial diagnosis of Henoch-Schönlein purpura (HSP), then urticarial vasculitis. She had been treated with antihistamines, topical and systemic steroids, hydroxychloroquine, mycophenolate mofetil, dapsone, azathioprine, and gabapentin. All treatments were ineffectual. She underwent extensive diagnostic testing and imaging, which were normal or noncontributory, including type I allergy testing; multiple exhaustive batteries of hematologic testing; and computed tomography/magnetic resonance imaging/magnetic resonance angiography of the brain, chest, abdomen, and pelvic region. Biopsies from symptomatic segments of the gastrointestinal tract were normal.

Chronic treatment with systemic steroids over 9 months resulted in gastritis and an episode of hematemesis requiring emergent hospitalization. A lengthy multidisciplinary evaluation was conducted at the patient’s local community hospital; the team concluded that she had an urticarial-type rash with accompanying symptoms that did not have an autoimmune, rheumatologic, or inflammatory basis.

The patient’s medical history was remarkable for recent-onset panic attacks. Her family medical history was noncontributory. Physical examination revealed multiple violaceous hyperpigmented patches diffusely located on the proximal upper arms (Figure 1). There were no additional findings on physical examination.

Punch biopsies were performed on lesional areas of the arm. Histopathology indicated a mild superficial perivascular dermal mixed infiltrate and extravasated erythrocytes (Figure 2). Direct immunofluorescence (DIF) testing was negative for vasculitis. Immunohistochemical stains for CD117 and tryptase demonstrated a slight increase in the number of dermal mast cells; however, the increase was not sufficient to diagnose cutaneous mastocytosis, which was in the differential. We proposed a diagnosis of psychogenic purpura (PP)(also known as Gardner-Diamond syndrome). She was treated with gabapentin, a selective serotonin reuptake inhibitor, and cognitive therapy. Unfortunately, after starting therapy the patient was lost to follow-up.

Psychogenic purpura is a rare vasculopathy of unknown etiology that may be a special form of factitious disorder.^1,2 In one study, PP occurred predominantly in females aged 15 to 66 years, with a median onset age of 33 years.³ A prodrome of localized itching, burning, and/or pain precedes the development of edematous plaques. The plaques evolve into painful ecchymoses within 1 to 2 days and resolve in 10 days or fewer without treatment. Lesions most commonly occur on the extremities but may occur anywhere on the body. The most common associated finding is an underlying depressive disorder. Episodes may be accompanied by headache, dizziness, fatigue, fever, arthralgia, nausea, vomiting, abdominal pain, menstrual irregularities, myalgia, and urologic conditions.

In 1955, Gardner and Diamond⁴ described the first cases of PP in 4 female patients at Peter Bent Brigham Hospital in Boston, Massachusetts. The investigators were able to replicate the painful ecchymoses with intradermal injection of the patient’s own erythrocytes into the skin. They proposed that the underlying pathogenesis involved autosensitization to erythrocyte stroma.⁴ Since then, others have suggested that the pathogenesis may include autosensitization to erythrocyte phosphatidylserine, tonus dysregulation of venous capillaries, abnormal endothelial fibrin synthesis, and capillary wall instability.^5-7 

 

Histopathology typically reveals superficial and deep perivascular inflammation with extravasated erythrocytes. Direct immunofluorescence is negative for vasculitis.⁸ Diagnostics and laboratory findings for underlying systemic illness are negative or noncontributory. Cutaneous injection of 1 mL of the patient’s own washed erythrocytes may result in the formation of the characteristic painful plaques within 24 hours; however, this test is limited by lack of standardization and low sensitivity.³

Psychogenic purpura may share clinical features with cutaneous small vessel vasculitis, such as HSP or urticarial vasculitis. Some of the findings that our patient was experiencing, including purpura, arthralgia, and abdominal pain, are associated with HSP. However, HSP typically is self-limiting and classically features palpable purpura distributed across the lower extremities and buttocks. Histopathology demonstrates the classic findings of leukocytoclastic vasculitis; DIF typically is positive for perivascular IgA and C3 deposition. Increased serum IgA may be present.⁹ Urticarial vasculitis appears as erythematous indurated wheals that favor a proximal extremity and truncal distribution. They characteristically last longer than 24 hours, are frequently associated with nonprodromal pain or burning, and resolve with hyperpigmentation. Arthralgia and gastrointestinal, renal, pulmonary, cardiac, and neurologic symptoms may be present, especially in patients with low complement levels.¹⁰ Skin biopsy demonstrates leukocytoclasia that must be accompanied by vessel wall necrosis. Fibrinoid deposition, erythrocyte extravasation, or perivascular inflammation may be present. In 70% of cases revealing perivascular immunoglobulin, C3, and fibrinogen deposition, DIF is positive. Serum C1q autoantibody may be associated with the hypocomplementemic form.¹⁰

The classic histopathologic findings in leukocytoclastic vasculitis include transmural neutrophilic infiltration of the walls of small vessels, fibrinoid necrosis of vessel walls, leukocytoclasia, extravasated erythrocytes, and signs of endothelial cell damage.⁹ A prior punch biopsy in this patient demonstrated rare neutrophilic nuclear debris within the vessel walls without fibrin deposition. Although the presence of nuclear debris and extravasated erythrocytes could be compatible with a manifestation of urticarial vasculitis, the lack of direct evidence of vessel wall necrosis combined with subsequent biopsies unequivocally ruled out cutaneous small vessel vasculitis in our patient.

Psychogenic purpura has been reported to occur frequently in the background of psycho-emotional distress. In 1989, Ratnoff¹¹ noted that many of the patients he was treating at the University Hospitals of Cleveland, Ohio, had a depressive syndrome. A review of patients treated at the Mayo Clinic in Rochester, Minnesota, illustrated concomitant psychiatric illnesses in 41 of 76 (54%) patients treated for PP, most commonly depressive, personality, and anxiety disorders.³

There is no consensus on therapy for PP. Treatment is based on providing symptomatic relief and relieving underlying psychiatric distress. Block et al¹² found the use of selective serotonin reuptake inhibitors, tricyclic antidepressants, and psychotherapy to be successful in improving symptoms and reducing lesions at follow-up visits.

To the Editor:

A 14-year-old Black adolescent girl presented with episodic, painful, edematous plaques that occurred symmetrically on the arms and legs of 5 years’ duration. The plaques evolved into hyperpigmented patches within 24 to 48 hours before eventually resolving. Fatigue, headache, arthralgias of the arms and legs, chest pain, abdominal pain, nausea, and vomiting variably accompanied these episodes.

Prior to visiting our clinic, the patient had been seen by numerous specialists. A review of her medical records revealed an initial diagnosis of Henoch-Schönlein purpura (HSP), then urticarial vasculitis. She had been treated with antihistamines, topical and systemic steroids, hydroxychloroquine, mycophenolate mofetil, dapsone, azathioprine, and gabapentin. All treatments were ineffectual. She underwent extensive diagnostic testing and imaging, which were normal or noncontributory, including type I allergy testing; multiple exhaustive batteries of hematologic testing; and computed tomography/magnetic resonance imaging/magnetic resonance angiography of the brain, chest, abdomen, and pelvic region. Biopsies from symptomatic segments of the gastrointestinal tract were normal.

Chronic treatment with systemic steroids over 9 months resulted in gastritis and an episode of hematemesis requiring emergent hospitalization. A lengthy multidisciplinary evaluation was conducted at the patient’s local community hospital; the team concluded that she had an urticarial-type rash with accompanying symptoms that did not have an autoimmune, rheumatologic, or inflammatory basis.

The patient’s medical history was remarkable for recent-onset panic attacks. Her family medical history was noncontributory. Physical examination revealed multiple violaceous hyperpigmented patches diffusely located on the proximal upper arms (Figure 1). There were no additional findings on physical examination.

Punch biopsies were performed on lesional areas of the arm. Histopathology indicated a mild superficial perivascular dermal mixed infiltrate and extravasated erythrocytes (Figure 2). Direct immunofluorescence (DIF) testing was negative for vasculitis. Immunohistochemical stains for CD117 and tryptase demonstrated a slight increase in the number of dermal mast cells; however, the increase was not sufficient to diagnose cutaneous mastocytosis, which was in the differential. We proposed a diagnosis of psychogenic purpura (PP)(also known as Gardner-Diamond syndrome). She was treated with gabapentin, a selective serotonin reuptake inhibitor, and cognitive therapy. Unfortunately, after starting therapy the patient was lost to follow-up.

Psychogenic purpura is a rare vasculopathy of unknown etiology that may be a special form of factitious disorder.^1,2 In one study, PP occurred predominantly in females aged 15 to 66 years, with a median onset age of 33 years.³ A prodrome of localized itching, burning, and/or pain precedes the development of edematous plaques. The plaques evolve into painful ecchymoses within 1 to 2 days and resolve in 10 days or fewer without treatment. Lesions most commonly occur on the extremities but may occur anywhere on the body. The most common associated finding is an underlying depressive disorder. Episodes may be accompanied by headache, dizziness, fatigue, fever, arthralgia, nausea, vomiting, abdominal pain, menstrual irregularities, myalgia, and urologic conditions.

In 1955, Gardner and Diamond⁴ described the first cases of PP in 4 female patients at Peter Bent Brigham Hospital in Boston, Massachusetts. The investigators were able to replicate the painful ecchymoses with intradermal injection of the patient’s own erythrocytes into the skin. They proposed that the underlying pathogenesis involved autosensitization to erythrocyte stroma.⁴ Since then, others have suggested that the pathogenesis may include autosensitization to erythrocyte phosphatidylserine, tonus dysregulation of venous capillaries, abnormal endothelial fibrin synthesis, and capillary wall instability.^5-7 

 

Histopathology typically reveals superficial and deep perivascular inflammation with extravasated erythrocytes. Direct immunofluorescence is negative for vasculitis.⁸ Diagnostics and laboratory findings for underlying systemic illness are negative or noncontributory. Cutaneous injection of 1 mL of the patient’s own washed erythrocytes may result in the formation of the characteristic painful plaques within 24 hours; however, this test is limited by lack of standardization and low sensitivity.³

Psychogenic purpura may share clinical features with cutaneous small vessel vasculitis, such as HSP or urticarial vasculitis. Some of the findings that our patient was experiencing, including purpura, arthralgia, and abdominal pain, are associated with HSP. However, HSP typically is self-limiting and classically features palpable purpura distributed across the lower extremities and buttocks. Histopathology demonstrates the classic findings of leukocytoclastic vasculitis; DIF typically is positive for perivascular IgA and C3 deposition. Increased serum IgA may be present.⁹ Urticarial vasculitis appears as erythematous indurated wheals that favor a proximal extremity and truncal distribution. They characteristically last longer than 24 hours, are frequently associated with nonprodromal pain or burning, and resolve with hyperpigmentation. Arthralgia and gastrointestinal, renal, pulmonary, cardiac, and neurologic symptoms may be present, especially in patients with low complement levels.¹⁰ Skin biopsy demonstrates leukocytoclasia that must be accompanied by vessel wall necrosis. Fibrinoid deposition, erythrocyte extravasation, or perivascular inflammation may be present. In 70% of cases revealing perivascular immunoglobulin, C3, and fibrinogen deposition, DIF is positive. Serum C1q autoantibody may be associated with the hypocomplementemic form.¹⁰

The classic histopathologic findings in leukocytoclastic vasculitis include transmural neutrophilic infiltration of the walls of small vessels, fibrinoid necrosis of vessel walls, leukocytoclasia, extravasated erythrocytes, and signs of endothelial cell damage.⁹ A prior punch biopsy in this patient demonstrated rare neutrophilic nuclear debris within the vessel walls without fibrin deposition. Although the presence of nuclear debris and extravasated erythrocytes could be compatible with a manifestation of urticarial vasculitis, the lack of direct evidence of vessel wall necrosis combined with subsequent biopsies unequivocally ruled out cutaneous small vessel vasculitis in our patient.

Psychogenic purpura has been reported to occur frequently in the background of psycho-emotional distress. In 1989, Ratnoff¹¹ noted that many of the patients he was treating at the University Hospitals of Cleveland, Ohio, had a depressive syndrome. A review of patients treated at the Mayo Clinic in Rochester, Minnesota, illustrated concomitant psychiatric illnesses in 41 of 76 (54%) patients treated for PP, most commonly depressive, personality, and anxiety disorders.³

There is no consensus on therapy for PP. Treatment is based on providing symptomatic relief and relieving underlying psychiatric distress. Block et al¹² found the use of selective serotonin reuptake inhibitors, tricyclic antidepressants, and psychotherapy to be successful in improving symptoms and reducing lesions at follow-up visits.

Characteristics

Rhipicephalus ticks belong to the Ixodidae family of hard-bodied ticks. They are large and teardrop shaped with an inornate scutum (hard dorsal plate) and relatively short mouthparts attached at a hexagonal basis capitulum (base of the head to which mouthparts are attached)(Figure).¹ Widely spaced eyes and festoons also are present. The first pair of coxae—attachment base for the first pair of legs—are characteristically bifid; males have a pair of sclerotized adanal plates on the ventral surface adjacent to the anus as well as accessory adanal shields.² Rhipicephalus (formerly Boophilus) microplus (the so-called cattle tick) is a newly added species; it lacks posterior festoons, and the anal groove is absent.³

Almost all Rhipicephalus ticks, except for R microplus, are 3-host ticks in which a single blood meal is consumed from a vertebrate host at each active life stage—larva, nymph, and adult—to complete development.^4,5 In contrast to most ixodid ticks, which are exophilic (living outside of human habitation), the Rhipicephalus sanguineus sensu lato species (the brown dog tick) is highly endophilic (adapted to indoor living) and often can be found hidden in cracks and crevices of walls in homes and peridomestic structures.⁶ It is predominately monotropic (all developmental stages feed on the same host species) and has a strong host preference for dogs, though it occasionally feeds on other hosts (eg, humans).⁷ Although most common in tropical and subtropical climates, they can be found anywhere there are dogs due to their ability to colonize indoor dwellings.⁸ In contrast, R microplus ticks have a predilection for cattle and livestock rather than humans, posing a notable concern to livestock worldwide. Infestation results in transmission of disease-causing pathogens, such as Babesia and Anaplasma species, which costs the cattle industry billions of dollars annually.⁹

Clinical Manifestations and Treatment

Tick bites usually manifest as intensely pruritic, erythematous papules at the site of tick attachment due to a local type IV hypersensitivity reaction to antigens in the tick’s saliva. This reaction can be long-lasting. In addition to pruritic papules following a bite, an attached tick can be mistaken for a skin neoplasm or nevus. Given that ticks are small, especially during the larval stage, dermoscopy may be helpful in making a diagnosis.¹⁰ Symptomatic relief usually can be achieved with topical antipruritics or oral antihistamines.

Of public health concern, brown dog ticks are important vectors of Rickettsia rickettsii (the causative organism of Rocky Mountain spotted fever [RMSF]) in the Western hemisphere, and Rickettsia conorii (the causative organism of Mediterranean spotted fever [MSF][also known as Boutonneuse fever]) in the Eastern hemisphere.¹¹ Bites by ticks carrying rickettsial disease classically manifest with early symptoms of fever, headache, and myalgia, followed by a rash or by a localized eschar or tache noire (a black, necrotic, scabbed lesion) that represents direct endothelial invasion and vascular damage by Rickettsia.¹² Rocky Mountain spotted fever and MSF are more prevalent during summer, likely due, in part, to the combination of increased outdoor activity and a higher rate of tick-questing (host-seeking) behavior in warmer climates.^4,7

Rocky Mountain Spotted Fever—Dermacentor variabilis is the primary vector of RMSF in the southeastern United States; Dermacentor andersoni is the major vector of RMSF in Rocky Mountain states. Rhipicephalus sanguineus sensu lato is an important vector of RMSF in the southwestern United States, Mexico, and Central America.^11,13

Early symptoms of RMSF are nonspecific and can include fever, headache, arthralgia, myalgia, and malaise. Gastrointestinal tract symptoms (eg, nausea, vomiting, anorexia) may occur; notable abdominal pain occurs in some patients, particularly children. A characteristic petechial rash occurs in as many as 90% of patients, typically at the third to fifth day of illness, and classically begins on the wrists and ankles, with progression to the palms and soles before spreading centripetally to the arms, legs, and trunk.¹⁴ An eschar at the inoculation site is uncommon in RMSF; when present, it is more suggestive of MSF.¹⁵

The classic triad of fever, headache, and rash is present in 3% of patients during the first 3 days after a tick bite and in 60% to 70% within 2 weeks.¹⁶ A rash often is absent when patients first seek medical attention and may not develop (absent in 9% to 12% of cases; so-called spotless RMSF). Therefore, absence of rash should not be a reason to withhold treatment.¹⁶ Empiric treatment with doxycycline should be started promptly for all suspected cases of RMSF because of the rapid progression of disease and an increased risk for morbidity and mortality with delayed diagnosis.

 

Patients do not become antibody positive until 7 to 10 days after symptoms begin; therefore, treatment should not be delayed while awaiting serologic test results. The case fatality rate in the United States is estimated to be 5% to 10% overall and as high as 40% to 50% among patients who are not treated until day 8 or 9 of illness.¹⁷

Cutaneous complications include skin necrosis and gangrene due to continuous tissue damage in severe cases.¹⁶ Severe infection also may manifest with signs of multiorgan system damage, including altered mental status, cerebral edema, meningismus, transient deafness, myocarditis, pulmonary hemorrhage and edema, conjunctivitis, retinal abnormalities, and acute renal failure.^14,16 Risk factors for more severe illness include delayed treatment, age 40 years or older or younger than 10 years, and underlying medical conditions such as alcoholic liver disease and glucose-6-phosphate dehydrogenase deficiency. However, even some healthy young patients die of this disease.¹⁷

Mediterranean Spotted Fever—Rhipicephalus sanguineus sensu lato is the primary vector of MSF, which is prevalent in areas adjacent to the Mediterranean Sea, including southern Europe, Africa, and Central Asia; Sicily is the most highly affected region.¹⁸ Findings with MSF are nearly identical to those of RMSF, except that tache noire is more common, present in as many as 70% of cases at the site of the inoculating tick bite, and MSF typically follows a less severe clinical course.¹² Similar to other rickettsial diseases, the pathogenesis of MSF involves direct injury to vascular endothelial cells, causing a vasculitis that is responsible for the clinical abnormalities observed.

Patients with severe MSF experience complications similar to severe RMSF, including neurologic manifestations and multiorgan damage.¹⁸ Risk factors include advanced age, immunocompromised state, cardiac disease, chronic alcoholism, diabetes mellitus, glucose-6-phosphate dehydrogenase deficiency, respiratory insufficiency, and delayed treatment.¹⁸

Treatment—For all spotted fever group rickettsial infections, doxycycline is the treatment of choice for all patients, including children and pregnant women. Treatment should be started without delay; recommended dosages are 100 mg twice daily for children weighing more than 45 kg and adults, and 2.2 mg/kg twice daily for children weighing 45 kg or less.¹²

Rhipicephalus tick bites rarely can result in paralysis; however, Dermacentor ticks are responsible for most cases of tick-related paralysis in North America. Other pathogens proven or reputed to be transmitted by Rhipicephalus sanguineus sensu lato with zoonotic potential include but are not limited to Rickettsia massiliae, Coxiella burnetti, Anaplasma platys, Leishmania infantum, and Crimean-Congo hemorrhagic fever virus (Nairovirus).¹⁹

Environmental Treatment and Prevention

The most effective way to prevent tick-borne illness is avoidance of tick bites. Primary prevention methods include vector control, use of repellents (eg, N,N-diethyl-meta-toluamide [DEET]), picaridin, permethrin), avoidance of areas with a high tick burden, use of protective clothing, and detection and removal of ticks as soon as possible.

 

Environmental and veterinary controls also are important methods of tick-bite prevention. A veterinarian can recommend a variety of agents for dogs and cats that prevent attachment of ticks. Environmental controls include synthetic or natural product-based chemical acaricides and nonchemical methods, such as landscape management (eg, sealing cracks and crevices in homes and controlling tall grasses, weeds, and leaf debris) to minimize potential tick habitat.²⁰ Secondary prevention includes antibiotics for prophylaxis or for treatment of tick-borne disease, when indicated.

Numerous tick repellents are available commercially; others are being studied. DEET, the most widely used topical repellent, has a broad spectrum of activity against many tick species.²¹ In addition, DEET has a well-known safety and toxicity profile, with rare adverse effects, and is safe for use in pregnant women and children older than 2 years. Alternative repellents, such as those containing picaridin, ethyl butylacetylaminopropionate (IR3535 [Merck]), oil of lemon eucalyptus, and 2-undecanone can be effective; some show efficacy comparable to that of DEET.²² Permethrin, a synthetic pyrethroid, is a highly efficacious tick repellent and insecticide, especially when used in conjunction with a topical repellent such as DEET. Unlike topically applied repellents, permethrin spray is applied to fabric (eg, clothing, shoes, bed nets, camping gear), not to skin.

Indiscriminate use of acaricides worldwide has led to increasing selection of acaricide resistance in Rhipicephalus tick species, which is especially true with the use of acaricides in controlling R microplus livestock infestations; several tick populations now show resistance to all major classes of these compounds.^23-25 For that reason, there has been an increasing effort to develop new chemical and nonchemical approaches to tick control that are more environmentally sustainable and strategies to minimize development and progression of resistance such as rotation of acaricides; reducing the frequency of their application; use of pesticide mixtures, synergists, or both; and increasing use of nonacaricidal methods of control.²⁶

Prompt removal of ticks is important for preventing the transmission of tick-borne disease. Proper removal involves rubbing the tick in a circular motion with a moist gauze pad or using fine-tipped tweezers to grasp the tick as close to the skin surface as possible and pulling upward with a steady pressure.^17,27 It is important not to jerk, twist, squeeze, smash, or burn the tick, as this can result in insufficient removal of mouthparts or spread contaminated tick fluids to mucous membranes, increasing the risk for infection. Application of petroleum jelly or nail polish to aid in tick removal have not been shown to be effective and are not recommended.^16,28

Characteristics

Rhipicephalus ticks belong to the Ixodidae family of hard-bodied ticks. They are large and teardrop shaped with an inornate scutum (hard dorsal plate) and relatively short mouthparts attached at a hexagonal basis capitulum (base of the head to which mouthparts are attached)(Figure).¹ Widely spaced eyes and festoons also are present. The first pair of coxae—attachment base for the first pair of legs—are characteristically bifid; males have a pair of sclerotized adanal plates on the ventral surface adjacent to the anus as well as accessory adanal shields.² Rhipicephalus (formerly Boophilus) microplus (the so-called cattle tick) is a newly added species; it lacks posterior festoons, and the anal groove is absent.³

Almost all Rhipicephalus ticks, except for R microplus, are 3-host ticks in which a single blood meal is consumed from a vertebrate host at each active life stage—larva, nymph, and adult—to complete development.^4,5 In contrast to most ixodid ticks, which are exophilic (living outside of human habitation), the Rhipicephalus sanguineus sensu lato species (the brown dog tick) is highly endophilic (adapted to indoor living) and often can be found hidden in cracks and crevices of walls in homes and peridomestic structures.⁶ It is predominately monotropic (all developmental stages feed on the same host species) and has a strong host preference for dogs, though it occasionally feeds on other hosts (eg, humans).⁷ Although most common in tropical and subtropical climates, they can be found anywhere there are dogs due to their ability to colonize indoor dwellings.⁸ In contrast, R microplus ticks have a predilection for cattle and livestock rather than humans, posing a notable concern to livestock worldwide. Infestation results in transmission of disease-causing pathogens, such as Babesia and Anaplasma species, which costs the cattle industry billions of dollars annually.⁹

Clinical Manifestations and Treatment

Tick bites usually manifest as intensely pruritic, erythematous papules at the site of tick attachment due to a local type IV hypersensitivity reaction to antigens in the tick’s saliva. This reaction can be long-lasting. In addition to pruritic papules following a bite, an attached tick can be mistaken for a skin neoplasm or nevus. Given that ticks are small, especially during the larval stage, dermoscopy may be helpful in making a diagnosis.¹⁰ Symptomatic relief usually can be achieved with topical antipruritics or oral antihistamines.

Of public health concern, brown dog ticks are important vectors of Rickettsia rickettsii (the causative organism of Rocky Mountain spotted fever [RMSF]) in the Western hemisphere, and Rickettsia conorii (the causative organism of Mediterranean spotted fever [MSF][also known as Boutonneuse fever]) in the Eastern hemisphere.¹¹ Bites by ticks carrying rickettsial disease classically manifest with early symptoms of fever, headache, and myalgia, followed by a rash or by a localized eschar or tache noire (a black, necrotic, scabbed lesion) that represents direct endothelial invasion and vascular damage by Rickettsia.¹² Rocky Mountain spotted fever and MSF are more prevalent during summer, likely due, in part, to the combination of increased outdoor activity and a higher rate of tick-questing (host-seeking) behavior in warmer climates.^4,7

Rocky Mountain Spotted Fever—Dermacentor variabilis is the primary vector of RMSF in the southeastern United States; Dermacentor andersoni is the major vector of RMSF in Rocky Mountain states. Rhipicephalus sanguineus sensu lato is an important vector of RMSF in the southwestern United States, Mexico, and Central America.^11,13

Early symptoms of RMSF are nonspecific and can include fever, headache, arthralgia, myalgia, and malaise. Gastrointestinal tract symptoms (eg, nausea, vomiting, anorexia) may occur; notable abdominal pain occurs in some patients, particularly children. A characteristic petechial rash occurs in as many as 90% of patients, typically at the third to fifth day of illness, and classically begins on the wrists and ankles, with progression to the palms and soles before spreading centripetally to the arms, legs, and trunk.¹⁴ An eschar at the inoculation site is uncommon in RMSF; when present, it is more suggestive of MSF.¹⁵

The classic triad of fever, headache, and rash is present in 3% of patients during the first 3 days after a tick bite and in 60% to 70% within 2 weeks.¹⁶ A rash often is absent when patients first seek medical attention and may not develop (absent in 9% to 12% of cases; so-called spotless RMSF). Therefore, absence of rash should not be a reason to withhold treatment.¹⁶ Empiric treatment with doxycycline should be started promptly for all suspected cases of RMSF because of the rapid progression of disease and an increased risk for morbidity and mortality with delayed diagnosis.

 

Patients do not become antibody positive until 7 to 10 days after symptoms begin; therefore, treatment should not be delayed while awaiting serologic test results. The case fatality rate in the United States is estimated to be 5% to 10% overall and as high as 40% to 50% among patients who are not treated until day 8 or 9 of illness.¹⁷

Cutaneous complications include skin necrosis and gangrene due to continuous tissue damage in severe cases.¹⁶ Severe infection also may manifest with signs of multiorgan system damage, including altered mental status, cerebral edema, meningismus, transient deafness, myocarditis, pulmonary hemorrhage and edema, conjunctivitis, retinal abnormalities, and acute renal failure.^14,16 Risk factors for more severe illness include delayed treatment, age 40 years or older or younger than 10 years, and underlying medical conditions such as alcoholic liver disease and glucose-6-phosphate dehydrogenase deficiency. However, even some healthy young patients die of this disease.¹⁷

Mediterranean Spotted Fever—Rhipicephalus sanguineus sensu lato is the primary vector of MSF, which is prevalent in areas adjacent to the Mediterranean Sea, including southern Europe, Africa, and Central Asia; Sicily is the most highly affected region.¹⁸ Findings with MSF are nearly identical to those of RMSF, except that tache noire is more common, present in as many as 70% of cases at the site of the inoculating tick bite, and MSF typically follows a less severe clinical course.¹² Similar to other rickettsial diseases, the pathogenesis of MSF involves direct injury to vascular endothelial cells, causing a vasculitis that is responsible for the clinical abnormalities observed.

Patients with severe MSF experience complications similar to severe RMSF, including neurologic manifestations and multiorgan damage.¹⁸ Risk factors include advanced age, immunocompromised state, cardiac disease, chronic alcoholism, diabetes mellitus, glucose-6-phosphate dehydrogenase deficiency, respiratory insufficiency, and delayed treatment.¹⁸

Treatment—For all spotted fever group rickettsial infections, doxycycline is the treatment of choice for all patients, including children and pregnant women. Treatment should be started without delay; recommended dosages are 100 mg twice daily for children weighing more than 45 kg and adults, and 2.2 mg/kg twice daily for children weighing 45 kg or less.¹²

Rhipicephalus tick bites rarely can result in paralysis; however, Dermacentor ticks are responsible for most cases of tick-related paralysis in North America. Other pathogens proven or reputed to be transmitted by Rhipicephalus sanguineus sensu lato with zoonotic potential include but are not limited to Rickettsia massiliae, Coxiella burnetti, Anaplasma platys, Leishmania infantum, and Crimean-Congo hemorrhagic fever virus (Nairovirus).¹⁹

Environmental Treatment and Prevention

The most effective way to prevent tick-borne illness is avoidance of tick bites. Primary prevention methods include vector control, use of repellents (eg, N,N-diethyl-meta-toluamide [DEET]), picaridin, permethrin), avoidance of areas with a high tick burden, use of protective clothing, and detection and removal of ticks as soon as possible.

 

Environmental and veterinary controls also are important methods of tick-bite prevention. A veterinarian can recommend a variety of agents for dogs and cats that prevent attachment of ticks. Environmental controls include synthetic or natural product-based chemical acaricides and nonchemical methods, such as landscape management (eg, sealing cracks and crevices in homes and controlling tall grasses, weeds, and leaf debris) to minimize potential tick habitat.²⁰ Secondary prevention includes antibiotics for prophylaxis or for treatment of tick-borne disease, when indicated.

Numerous tick repellents are available commercially; others are being studied. DEET, the most widely used topical repellent, has a broad spectrum of activity against many tick species.²¹ In addition, DEET has a well-known safety and toxicity profile, with rare adverse effects, and is safe for use in pregnant women and children older than 2 years. Alternative repellents, such as those containing picaridin, ethyl butylacetylaminopropionate (IR3535 [Merck]), oil of lemon eucalyptus, and 2-undecanone can be effective; some show efficacy comparable to that of DEET.²² Permethrin, a synthetic pyrethroid, is a highly efficacious tick repellent and insecticide, especially when used in conjunction with a topical repellent such as DEET. Unlike topically applied repellents, permethrin spray is applied to fabric (eg, clothing, shoes, bed nets, camping gear), not to skin.

Indiscriminate use of acaricides worldwide has led to increasing selection of acaricide resistance in Rhipicephalus tick species, which is especially true with the use of acaricides in controlling R microplus livestock infestations; several tick populations now show resistance to all major classes of these compounds.^23-25 For that reason, there has been an increasing effort to develop new chemical and nonchemical approaches to tick control that are more environmentally sustainable and strategies to minimize development and progression of resistance such as rotation of acaricides; reducing the frequency of their application; use of pesticide mixtures, synergists, or both; and increasing use of nonacaricidal methods of control.²⁶

Prompt removal of ticks is important for preventing the transmission of tick-borne disease. Proper removal involves rubbing the tick in a circular motion with a moist gauze pad or using fine-tipped tweezers to grasp the tick as close to the skin surface as possible and pulling upward with a steady pressure.^17,27 It is important not to jerk, twist, squeeze, smash, or burn the tick, as this can result in insufficient removal of mouthparts or spread contaminated tick fluids to mucous membranes, increasing the risk for infection. Application of petroleum jelly or nail polish to aid in tick removal have not been shown to be effective and are not recommended.^16,28

Characteristics

Rhipicephalus ticks belong to the Ixodidae family of hard-bodied ticks. They are large and teardrop shaped with an inornate scutum (hard dorsal plate) and relatively short mouthparts attached at a hexagonal basis capitulum (base of the head to which mouthparts are attached)(Figure).¹ Widely spaced eyes and festoons also are present. The first pair of coxae—attachment base for the first pair of legs—are characteristically bifid; males have a pair of sclerotized adanal plates on the ventral surface adjacent to the anus as well as accessory adanal shields.² Rhipicephalus (formerly Boophilus) microplus (the so-called cattle tick) is a newly added species; it lacks posterior festoons, and the anal groove is absent.³

Almost all Rhipicephalus ticks, except for R microplus, are 3-host ticks in which a single blood meal is consumed from a vertebrate host at each active life stage—larva, nymph, and adult—to complete development.^4,5 In contrast to most ixodid ticks, which are exophilic (living outside of human habitation), the Rhipicephalus sanguineus sensu lato species (the brown dog tick) is highly endophilic (adapted to indoor living) and often can be found hidden in cracks and crevices of walls in homes and peridomestic structures.⁶ It is predominately monotropic (all developmental stages feed on the same host species) and has a strong host preference for dogs, though it occasionally feeds on other hosts (eg, humans).⁷ Although most common in tropical and subtropical climates, they can be found anywhere there are dogs due to their ability to colonize indoor dwellings.⁸ In contrast, R microplus ticks have a predilection for cattle and livestock rather than humans, posing a notable concern to livestock worldwide. Infestation results in transmission of disease-causing pathogens, such as Babesia and Anaplasma species, which costs the cattle industry billions of dollars annually.⁹

Clinical Manifestations and Treatment

Tick bites usually manifest as intensely pruritic, erythematous papules at the site of tick attachment due to a local type IV hypersensitivity reaction to antigens in the tick’s saliva. This reaction can be long-lasting. In addition to pruritic papules following a bite, an attached tick can be mistaken for a skin neoplasm or nevus. Given that ticks are small, especially during the larval stage, dermoscopy may be helpful in making a diagnosis.¹⁰ Symptomatic relief usually can be achieved with topical antipruritics or oral antihistamines.

Of public health concern, brown dog ticks are important vectors of Rickettsia rickettsii (the causative organism of Rocky Mountain spotted fever [RMSF]) in the Western hemisphere, and Rickettsia conorii (the causative organism of Mediterranean spotted fever [MSF][also known as Boutonneuse fever]) in the Eastern hemisphere.¹¹ Bites by ticks carrying rickettsial disease classically manifest with early symptoms of fever, headache, and myalgia, followed by a rash or by a localized eschar or tache noire (a black, necrotic, scabbed lesion) that represents direct endothelial invasion and vascular damage by Rickettsia.¹² Rocky Mountain spotted fever and MSF are more prevalent during summer, likely due, in part, to the combination of increased outdoor activity and a higher rate of tick-questing (host-seeking) behavior in warmer climates.^4,7

Rocky Mountain Spotted Fever—Dermacentor variabilis is the primary vector of RMSF in the southeastern United States; Dermacentor andersoni is the major vector of RMSF in Rocky Mountain states. Rhipicephalus sanguineus sensu lato is an important vector of RMSF in the southwestern United States, Mexico, and Central America.^11,13

Early symptoms of RMSF are nonspecific and can include fever, headache, arthralgia, myalgia, and malaise. Gastrointestinal tract symptoms (eg, nausea, vomiting, anorexia) may occur; notable abdominal pain occurs in some patients, particularly children. A characteristic petechial rash occurs in as many as 90% of patients, typically at the third to fifth day of illness, and classically begins on the wrists and ankles, with progression to the palms and soles before spreading centripetally to the arms, legs, and trunk.¹⁴ An eschar at the inoculation site is uncommon in RMSF; when present, it is more suggestive of MSF.¹⁵

The classic triad of fever, headache, and rash is present in 3% of patients during the first 3 days after a tick bite and in 60% to 70% within 2 weeks.¹⁶ A rash often is absent when patients first seek medical attention and may not develop (absent in 9% to 12% of cases; so-called spotless RMSF). Therefore, absence of rash should not be a reason to withhold treatment.¹⁶ Empiric treatment with doxycycline should be started promptly for all suspected cases of RMSF because of the rapid progression of disease and an increased risk for morbidity and mortality with delayed diagnosis.

 

Patients do not become antibody positive until 7 to 10 days after symptoms begin; therefore, treatment should not be delayed while awaiting serologic test results. The case fatality rate in the United States is estimated to be 5% to 10% overall and as high as 40% to 50% among patients who are not treated until day 8 or 9 of illness.¹⁷

Cutaneous complications include skin necrosis and gangrene due to continuous tissue damage in severe cases.¹⁶ Severe infection also may manifest with signs of multiorgan system damage, including altered mental status, cerebral edema, meningismus, transient deafness, myocarditis, pulmonary hemorrhage and edema, conjunctivitis, retinal abnormalities, and acute renal failure.^14,16 Risk factors for more severe illness include delayed treatment, age 40 years or older or younger than 10 years, and underlying medical conditions such as alcoholic liver disease and glucose-6-phosphate dehydrogenase deficiency. However, even some healthy young patients die of this disease.¹⁷

Mediterranean Spotted Fever—Rhipicephalus sanguineus sensu lato is the primary vector of MSF, which is prevalent in areas adjacent to the Mediterranean Sea, including southern Europe, Africa, and Central Asia; Sicily is the most highly affected region.¹⁸ Findings with MSF are nearly identical to those of RMSF, except that tache noire is more common, present in as many as 70% of cases at the site of the inoculating tick bite, and MSF typically follows a less severe clinical course.¹² Similar to other rickettsial diseases, the pathogenesis of MSF involves direct injury to vascular endothelial cells, causing a vasculitis that is responsible for the clinical abnormalities observed.

Patients with severe MSF experience complications similar to severe RMSF, including neurologic manifestations and multiorgan damage.¹⁸ Risk factors include advanced age, immunocompromised state, cardiac disease, chronic alcoholism, diabetes mellitus, glucose-6-phosphate dehydrogenase deficiency, respiratory insufficiency, and delayed treatment.¹⁸

Treatment—For all spotted fever group rickettsial infections, doxycycline is the treatment of choice for all patients, including children and pregnant women. Treatment should be started without delay; recommended dosages are 100 mg twice daily for children weighing more than 45 kg and adults, and 2.2 mg/kg twice daily for children weighing 45 kg or less.¹²

Rhipicephalus tick bites rarely can result in paralysis; however, Dermacentor ticks are responsible for most cases of tick-related paralysis in North America. Other pathogens proven or reputed to be transmitted by Rhipicephalus sanguineus sensu lato with zoonotic potential include but are not limited to Rickettsia massiliae, Coxiella burnetti, Anaplasma platys, Leishmania infantum, and Crimean-Congo hemorrhagic fever virus (Nairovirus).¹⁹

Environmental Treatment and Prevention

The most effective way to prevent tick-borne illness is avoidance of tick bites. Primary prevention methods include vector control, use of repellents (eg, N,N-diethyl-meta-toluamide [DEET]), picaridin, permethrin), avoidance of areas with a high tick burden, use of protective clothing, and detection and removal of ticks as soon as possible.

 

Environmental and veterinary controls also are important methods of tick-bite prevention. A veterinarian can recommend a variety of agents for dogs and cats that prevent attachment of ticks. Environmental controls include synthetic or natural product-based chemical acaricides and nonchemical methods, such as landscape management (eg, sealing cracks and crevices in homes and controlling tall grasses, weeds, and leaf debris) to minimize potential tick habitat.²⁰ Secondary prevention includes antibiotics for prophylaxis or for treatment of tick-borne disease, when indicated.

Numerous tick repellents are available commercially; others are being studied. DEET, the most widely used topical repellent, has a broad spectrum of activity against many tick species.²¹ In addition, DEET has a well-known safety and toxicity profile, with rare adverse effects, and is safe for use in pregnant women and children older than 2 years. Alternative repellents, such as those containing picaridin, ethyl butylacetylaminopropionate (IR3535 [Merck]), oil of lemon eucalyptus, and 2-undecanone can be effective; some show efficacy comparable to that of DEET.²² Permethrin, a synthetic pyrethroid, is a highly efficacious tick repellent and insecticide, especially when used in conjunction with a topical repellent such as DEET. Unlike topically applied repellents, permethrin spray is applied to fabric (eg, clothing, shoes, bed nets, camping gear), not to skin.

Indiscriminate use of acaricides worldwide has led to increasing selection of acaricide resistance in Rhipicephalus tick species, which is especially true with the use of acaricides in controlling R microplus livestock infestations; several tick populations now show resistance to all major classes of these compounds.^23-25 For that reason, there has been an increasing effort to develop new chemical and nonchemical approaches to tick control that are more environmentally sustainable and strategies to minimize development and progression of resistance such as rotation of acaricides; reducing the frequency of their application; use of pesticide mixtures, synergists, or both; and increasing use of nonacaricidal methods of control.²⁶

Prompt removal of ticks is important for preventing the transmission of tick-borne disease. Proper removal involves rubbing the tick in a circular motion with a moist gauze pad or using fine-tipped tweezers to grasp the tick as close to the skin surface as possible and pulling upward with a steady pressure.^17,27 It is important not to jerk, twist, squeeze, smash, or burn the tick, as this can result in insufficient removal of mouthparts or spread contaminated tick fluids to mucous membranes, increasing the risk for infection. Application of petroleum jelly or nail polish to aid in tick removal have not been shown to be effective and are not recommended.^16,28

The Diagnosis: Giant Apocrine Hidrocystoma

Histopathology of the noduloplaque revealed an unremarkable epidermis with multilocular cystic spaces centered in the dermis. The cysts had a double-lined epithelium with inner columnar to cuboidal cells and outer myoepithelial cells (bottom quiz image). Columnar cells showing decapitation secretion could be appreciated at places indicating apocrine secretion (Figure). A final diagnosis of apocrine hidrocystoma was made.

Hidrocystomas are rare, benign, cystic lesions derived either from apocrine or eccrine glands.¹ Apocrine hidrocystoma usually manifests as asymptomatic, solitary, dome-shaped papules or nodules with a predilection for the head and neck region. Hidrocystomas can vary from flesh colored to blue, brown, or black. Pigmentation in hidrocystoma is seen in 5% to 80% of cases and is attributed to the Tyndall effect.¹ The tumor usually is less than 20 mm in diameter; larger lesions are termed giant apocrine hidrocystoma.² Apocrine hidrocystoma manifesting with multiple lesions and a size greater than 10 mm, as seen in our case, is uncommon.

Zaballos et al³ described dermoscopy of apocrine hidrocystoma in 22 patients. Hallmark dermoscopic findings were the presence of a homogeneous flesh-colored, yellowish, blue to pinkish-blue area involving the entire lesion with arborizing vessels and whitish structures.³ Similar dermoscopic findings were present in our patient. The homogeneous area histologically correlates to the multiloculated cysts located in the dermis. The exact reason for white structures is unknown; however, their visualization in apocrine hidrocystoma could be attributed to the alternation in collagen orientation secondary to the presence of large or multiple cysts in the dermis.

The presence of shiny white dots arranged in a square resembling a four-leaf clover (also known as white rosettes) was a unique dermoscopic finding in our patient. These rosettes can be appreciated only with polarized dermoscopy, and they have been described in actinic keratosis, seborrheic keratosis, squamous cell carcinoma, and basal cell carcinoma.⁴ The exact morphologic correlate of white rosettes is unknown but is postulated to be secondary to material inside adnexal openings in small rosettes and concentric perifollicular fibrosis in larger rosettes.⁴ In our patient, we believe the white rosettes can be attributed to the accumulated secretions in the dermal glands, which also were seen via histopathology. Dermoscopy also revealed increased peripheral, brown, networklike pigmentation, which was unique and could be secondary to the patient’s darker skin phenotype.

Differential diagnoses of apocrine hidrocystoma include both melanocytic and nonmelanocytic conditions such as epidermal cyst, nodular melanoma, nodular hidradenoma, syringoma, blue nevus, pilomatricoma, eccrine poroma, nodular Kaposi sarcoma, and venous lake.1 Histopathology showing large unilocular or multilocular dermal cysts with double lining comprising outer myoepithelial cells and inner columnar or cuboidal cell with decapitation secretion is paramount in confirming the diagnosis of apocrine hidrocystoma.

Dermoscopy can act as a valuable noninvasive modality in differentiating apocrine hidrocystoma from its melanocytic and nonmelanocytic differential diagnoses (Table).^5-8 In our patient, the presence of a homogeneous pink to bluish area involving the entire lesion, linear branched vessels, and whitish structures on dermoscopy pointed to the diagnosis of apocrine hidrocystoma, which was further confirmed by characteristic histopathologic findings.

The treatment of apocrine hidrocystoma includes surgical excision for solitary lesions, with electrodesiccation and curettage, chemical cautery, and CO₂ laser ablation employed for multiple lesions.¹ Our patient was scheduled for CO₂ laser ablation, considering the multiple lesions and size of the apocrine hidrocystoma but was subsequently lost to follow-up.

The Diagnosis: Giant Apocrine Hidrocystoma

Histopathology of the noduloplaque revealed an unremarkable epidermis with multilocular cystic spaces centered in the dermis. The cysts had a double-lined epithelium with inner columnar to cuboidal cells and outer myoepithelial cells (bottom quiz image). Columnar cells showing decapitation secretion could be appreciated at places indicating apocrine secretion (Figure). A final diagnosis of apocrine hidrocystoma was made.

Hidrocystomas are rare, benign, cystic lesions derived either from apocrine or eccrine glands.¹ Apocrine hidrocystoma usually manifests as asymptomatic, solitary, dome-shaped papules or nodules with a predilection for the head and neck region. Hidrocystomas can vary from flesh colored to blue, brown, or black. Pigmentation in hidrocystoma is seen in 5% to 80% of cases and is attributed to the Tyndall effect.¹ The tumor usually is less than 20 mm in diameter; larger lesions are termed giant apocrine hidrocystoma.² Apocrine hidrocystoma manifesting with multiple lesions and a size greater than 10 mm, as seen in our case, is uncommon.

Zaballos et al³ described dermoscopy of apocrine hidrocystoma in 22 patients. Hallmark dermoscopic findings were the presence of a homogeneous flesh-colored, yellowish, blue to pinkish-blue area involving the entire lesion with arborizing vessels and whitish structures.³ Similar dermoscopic findings were present in our patient. The homogeneous area histologically correlates to the multiloculated cysts located in the dermis. The exact reason for white structures is unknown; however, their visualization in apocrine hidrocystoma could be attributed to the alternation in collagen orientation secondary to the presence of large or multiple cysts in the dermis.

The presence of shiny white dots arranged in a square resembling a four-leaf clover (also known as white rosettes) was a unique dermoscopic finding in our patient. These rosettes can be appreciated only with polarized dermoscopy, and they have been described in actinic keratosis, seborrheic keratosis, squamous cell carcinoma, and basal cell carcinoma.⁴ The exact morphologic correlate of white rosettes is unknown but is postulated to be secondary to material inside adnexal openings in small rosettes and concentric perifollicular fibrosis in larger rosettes.⁴ In our patient, we believe the white rosettes can be attributed to the accumulated secretions in the dermal glands, which also were seen via histopathology. Dermoscopy also revealed increased peripheral, brown, networklike pigmentation, which was unique and could be secondary to the patient’s darker skin phenotype.

Differential diagnoses of apocrine hidrocystoma include both melanocytic and nonmelanocytic conditions such as epidermal cyst, nodular melanoma, nodular hidradenoma, syringoma, blue nevus, pilomatricoma, eccrine poroma, nodular Kaposi sarcoma, and venous lake.1 Histopathology showing large unilocular or multilocular dermal cysts with double lining comprising outer myoepithelial cells and inner columnar or cuboidal cell with decapitation secretion is paramount in confirming the diagnosis of apocrine hidrocystoma.

Dermoscopy can act as a valuable noninvasive modality in differentiating apocrine hidrocystoma from its melanocytic and nonmelanocytic differential diagnoses (Table).^5-8 In our patient, the presence of a homogeneous pink to bluish area involving the entire lesion, linear branched vessels, and whitish structures on dermoscopy pointed to the diagnosis of apocrine hidrocystoma, which was further confirmed by characteristic histopathologic findings.

The treatment of apocrine hidrocystoma includes surgical excision for solitary lesions, with electrodesiccation and curettage, chemical cautery, and CO₂ laser ablation employed for multiple lesions.¹ Our patient was scheduled for CO₂ laser ablation, considering the multiple lesions and size of the apocrine hidrocystoma but was subsequently lost to follow-up.

The Diagnosis: Giant Apocrine Hidrocystoma

Histopathology of the noduloplaque revealed an unremarkable epidermis with multilocular cystic spaces centered in the dermis. The cysts had a double-lined epithelium with inner columnar to cuboidal cells and outer myoepithelial cells (bottom quiz image). Columnar cells showing decapitation secretion could be appreciated at places indicating apocrine secretion (Figure). A final diagnosis of apocrine hidrocystoma was made.

Hidrocystomas are rare, benign, cystic lesions derived either from apocrine or eccrine glands.¹ Apocrine hidrocystoma usually manifests as asymptomatic, solitary, dome-shaped papules or nodules with a predilection for the head and neck region. Hidrocystomas can vary from flesh colored to blue, brown, or black. Pigmentation in hidrocystoma is seen in 5% to 80% of cases and is attributed to the Tyndall effect.¹ The tumor usually is less than 20 mm in diameter; larger lesions are termed giant apocrine hidrocystoma.² Apocrine hidrocystoma manifesting with multiple lesions and a size greater than 10 mm, as seen in our case, is uncommon.

Zaballos et al³ described dermoscopy of apocrine hidrocystoma in 22 patients. Hallmark dermoscopic findings were the presence of a homogeneous flesh-colored, yellowish, blue to pinkish-blue area involving the entire lesion with arborizing vessels and whitish structures.³ Similar dermoscopic findings were present in our patient. The homogeneous area histologically correlates to the multiloculated cysts located in the dermis. The exact reason for white structures is unknown; however, their visualization in apocrine hidrocystoma could be attributed to the alternation in collagen orientation secondary to the presence of large or multiple cysts in the dermis.

The presence of shiny white dots arranged in a square resembling a four-leaf clover (also known as white rosettes) was a unique dermoscopic finding in our patient. These rosettes can be appreciated only with polarized dermoscopy, and they have been described in actinic keratosis, seborrheic keratosis, squamous cell carcinoma, and basal cell carcinoma.⁴ The exact morphologic correlate of white rosettes is unknown but is postulated to be secondary to material inside adnexal openings in small rosettes and concentric perifollicular fibrosis in larger rosettes.⁴ In our patient, we believe the white rosettes can be attributed to the accumulated secretions in the dermal glands, which also were seen via histopathology. Dermoscopy also revealed increased peripheral, brown, networklike pigmentation, which was unique and could be secondary to the patient’s darker skin phenotype.

Differential diagnoses of apocrine hidrocystoma include both melanocytic and nonmelanocytic conditions such as epidermal cyst, nodular melanoma, nodular hidradenoma, syringoma, blue nevus, pilomatricoma, eccrine poroma, nodular Kaposi sarcoma, and venous lake.1 Histopathology showing large unilocular or multilocular dermal cysts with double lining comprising outer myoepithelial cells and inner columnar or cuboidal cell with decapitation secretion is paramount in confirming the diagnosis of apocrine hidrocystoma.

Dermoscopy can act as a valuable noninvasive modality in differentiating apocrine hidrocystoma from its melanocytic and nonmelanocytic differential diagnoses (Table).^5-8 In our patient, the presence of a homogeneous pink to bluish area involving the entire lesion, linear branched vessels, and whitish structures on dermoscopy pointed to the diagnosis of apocrine hidrocystoma, which was further confirmed by characteristic histopathologic findings.

The treatment of apocrine hidrocystoma includes surgical excision for solitary lesions, with electrodesiccation and curettage, chemical cautery, and CO₂ laser ablation employed for multiple lesions.¹ Our patient was scheduled for CO₂ laser ablation, considering the multiple lesions and size of the apocrine hidrocystoma but was subsequently lost to follow-up.

The Diagnosis: Coral Dermatitis

At 3-week follow-up, the patient demonstrated remarkable improvement in the intensity and size of the erythematous cerebriform plaques following daily application of triamcinolone acetonide cream 0.1% (Figure). The lesion disappeared after several months and did not recur. The delayed presentation of symptoms with a history of incidental coral contact during snorkeling most likely represents the type IV hypersensitivity reaction seen in the diagnosis of coral dermatitis, an extraordinarily rare form of contact dermatitis.¹ Not all coral trigger skin reactions. Species of coral that contain nematocysts in their tentacles (aptly named stinging capsules) are responsible for the sting preceding coral dermatitis, as the nematocysts eject a coiled filament in response to human tactile stimulation that injects toxins into the epidermis.²

Acute, delayed, or chronic cutaneous changes follow envenomation. Acute responses arise immediately to a few hours after initial contact and are considered an irritant contact dermatitis.³ Local tissue histamine release and cascades of cytotoxic reactions often result in the characteristic urticarial or vesiculobullous plaques in addition to necrosis, piloerection, and localized lymphadenopathy.^2-4 Although relatively uncommon, there may be rapid onset of systemic symptoms such as fever, malaise, hives, nausea, or emesis. Cardiopulmonary events, hepatotoxicity, renal failure, or anaphylaxis are rare.² Histopathology of biopsy specimens reveals epidermal spongiosis with microvesicles and papillary dermal edema.^1,5 In comparison, delayed reactions occur within days to weeks and exhibit epidermal parakeratosis, spongiosis, basal layer vacuolization, focal necrosis, lymphocyte exocytosis, and papillary dermal edema with extravasated erythrocytes.1,6 Clinically, it may present as linear rows of erythematous papules with burning and pruritus.⁶ Chronic reactions manifest after months as difficult-to-treat, persistent lichenoid dermatitis occasionally accompanied by granulomatous changes.^1,2,4 Primary prevention measures after initial contact include an acetic acid rinse and cold compression to wash away residual nematocysts in the affected area.^4,7,8 If a rash develops, topical steroids are the mainstay of treatment.^3,8

In tandem with toxic nematocysts, the rigid calcified bodies of coral provide an additional self-defense mechanism against human contact.^2,4 The irregular haphazard nature of coral may catch novice divers off guard and lead to laceration of a mispositioned limb, thereby increasing the risk for secondary infections due to the introduction of calcium carbonate and toxic mucinous deposits at the wound site, warranting antibiotic treatment.^2,4,7 Because tropical locales are home to other natural dangers that inflict disease and mimic early signs of coral dermatitis, reaching an accurate diagnosis can be difficult, particularly for lower limb lesions. In summary, the diagnosis of coral dermatitis can be rendered based on morphology of the lesion and clinical context (exposure to corals and delayed symptoms) as well as response to topical steroids.

The differential diagnosis includes accidental trauma. Variations in impact force and patient skin integrity lead to a number of possible cutaneous manifestations seen in accidental trauma,⁹ which includes contusions resulting from burst capillaries underneath intact skin, abrasions due to the superficial epidermis scuffing away, and lacerations caused by enough force to rip and split the skin, leaving subcutaneous tissue between the intact tissue.^9,10 Typically, the pattern of injury can provide hints to match what object or organism caused the wound.⁹ However, delayed response and worsening symptoms, as seen in coral dermatitis, would be unusual in accidental trauma unless it is complicated by secondary infection (infectious dermatitis), which does not respond to topical steroids and requires antibiotic treatment.

Another differential diagnosis includes cutaneous larva migrans, which infests domesticated and stray animals. For example, hookworm larvae propagate their eggs inside the intestines of their host before fecal-soil transmission in sandy locales.¹¹ Unexpecting beachgoers travel barefoot on this contaminated soil, offering ample opportunity for the parasite to burrow into the upper dermis.^11,12 The clinical presentation includes signs and symptoms of creeping eruption such as pruritic, linear, serpiginous tracks. Topical treatment with thiabendazole requires application 3 times daily for 15 days, which increases the risk for nonadherence, yet this therapy proves advantageous if a patient does not tolerate oral agents due to systemic adverse effects.^11,12 Oral agents (eg, ivermectin, albendazole) offer improved adherence with a single dose^11,13; the cure rate was higher with a single dose of ivermectin 12 mg vs a single dose of albendazole 400 mg.13 The current suggested treatment is ivermectin 200 μg/kg by mouth daily for 1 or 2 days.¹⁴

The incidence of seabather’s eruption (also known as chinkui dermatitis) is highest during the summer season and fluctuates between epidemic and nonepidemic years.^15,16 It occurs sporadically worldwide mostly in tropical climates due to trapping of larvae spawn of sea animals such as crustaceans in swimwear. Initially, it presents as a pruritic and burning sensation after exiting the water, manifesting as a macular, papular, or maculopapular rash on areas covered by the swimsuit.^15,16 The sensation is worse in areas that are tightly banded on the swimsuit, including the waistband and elastic straps.¹⁵ Commonly, the affected individual will seek relief via a shower, which intensifies the burning, especially if the swimsuit has not been removed. The contaminated swimwear should be immediately discarded, as the trapped sea larvae’s nematocysts activate with the pressure and friction of movement.¹⁵ Seabather’s eruption typically resolves spontaneously within a week, but symptom management can be achieved with topical steroids (triamcinolone 0.1% or clobetasol 0.05%).^15,16 Unlike coral dermatitis, in seabather’s eruption the symptoms are immediate and the location of the eruption coincides with areas covered by the swimsuit.

The Diagnosis: Coral Dermatitis

At 3-week follow-up, the patient demonstrated remarkable improvement in the intensity and size of the erythematous cerebriform plaques following daily application of triamcinolone acetonide cream 0.1% (Figure). The lesion disappeared after several months and did not recur. The delayed presentation of symptoms with a history of incidental coral contact during snorkeling most likely represents the type IV hypersensitivity reaction seen in the diagnosis of coral dermatitis, an extraordinarily rare form of contact dermatitis.¹ Not all coral trigger skin reactions. Species of coral that contain nematocysts in their tentacles (aptly named stinging capsules) are responsible for the sting preceding coral dermatitis, as the nematocysts eject a coiled filament in response to human tactile stimulation that injects toxins into the epidermis.²

Acute, delayed, or chronic cutaneous changes follow envenomation. Acute responses arise immediately to a few hours after initial contact and are considered an irritant contact dermatitis.³ Local tissue histamine release and cascades of cytotoxic reactions often result in the characteristic urticarial or vesiculobullous plaques in addition to necrosis, piloerection, and localized lymphadenopathy.^2-4 Although relatively uncommon, there may be rapid onset of systemic symptoms such as fever, malaise, hives, nausea, or emesis. Cardiopulmonary events, hepatotoxicity, renal failure, or anaphylaxis are rare.² Histopathology of biopsy specimens reveals epidermal spongiosis with microvesicles and papillary dermal edema.^1,5 In comparison, delayed reactions occur within days to weeks and exhibit epidermal parakeratosis, spongiosis, basal layer vacuolization, focal necrosis, lymphocyte exocytosis, and papillary dermal edema with extravasated erythrocytes.1,6 Clinically, it may present as linear rows of erythematous papules with burning and pruritus.⁶ Chronic reactions manifest after months as difficult-to-treat, persistent lichenoid dermatitis occasionally accompanied by granulomatous changes.^1,2,4 Primary prevention measures after initial contact include an acetic acid rinse and cold compression to wash away residual nematocysts in the affected area.^4,7,8 If a rash develops, topical steroids are the mainstay of treatment.^3,8

In tandem with toxic nematocysts, the rigid calcified bodies of coral provide an additional self-defense mechanism against human contact.^2,4 The irregular haphazard nature of coral may catch novice divers off guard and lead to laceration of a mispositioned limb, thereby increasing the risk for secondary infections due to the introduction of calcium carbonate and toxic mucinous deposits at the wound site, warranting antibiotic treatment.^2,4,7 Because tropical locales are home to other natural dangers that inflict disease and mimic early signs of coral dermatitis, reaching an accurate diagnosis can be difficult, particularly for lower limb lesions. In summary, the diagnosis of coral dermatitis can be rendered based on morphology of the lesion and clinical context (exposure to corals and delayed symptoms) as well as response to topical steroids.

The differential diagnosis includes accidental trauma. Variations in impact force and patient skin integrity lead to a number of possible cutaneous manifestations seen in accidental trauma,⁹ which includes contusions resulting from burst capillaries underneath intact skin, abrasions due to the superficial epidermis scuffing away, and lacerations caused by enough force to rip and split the skin, leaving subcutaneous tissue between the intact tissue.^9,10 Typically, the pattern of injury can provide hints to match what object or organism caused the wound.⁹ However, delayed response and worsening symptoms, as seen in coral dermatitis, would be unusual in accidental trauma unless it is complicated by secondary infection (infectious dermatitis), which does not respond to topical steroids and requires antibiotic treatment.

Another differential diagnosis includes cutaneous larva migrans, which infests domesticated and stray animals. For example, hookworm larvae propagate their eggs inside the intestines of their host before fecal-soil transmission in sandy locales.¹¹ Unexpecting beachgoers travel barefoot on this contaminated soil, offering ample opportunity for the parasite to burrow into the upper dermis.^11,12 The clinical presentation includes signs and symptoms of creeping eruption such as pruritic, linear, serpiginous tracks. Topical treatment with thiabendazole requires application 3 times daily for 15 days, which increases the risk for nonadherence, yet this therapy proves advantageous if a patient does not tolerate oral agents due to systemic adverse effects.^11,12 Oral agents (eg, ivermectin, albendazole) offer improved adherence with a single dose^11,13; the cure rate was higher with a single dose of ivermectin 12 mg vs a single dose of albendazole 400 mg.13 The current suggested treatment is ivermectin 200 μg/kg by mouth daily for 1 or 2 days.¹⁴

The incidence of seabather’s eruption (also known as chinkui dermatitis) is highest during the summer season and fluctuates between epidemic and nonepidemic years.^15,16 It occurs sporadically worldwide mostly in tropical climates due to trapping of larvae spawn of sea animals such as crustaceans in swimwear. Initially, it presents as a pruritic and burning sensation after exiting the water, manifesting as a macular, papular, or maculopapular rash on areas covered by the swimsuit.^15,16 The sensation is worse in areas that are tightly banded on the swimsuit, including the waistband and elastic straps.¹⁵ Commonly, the affected individual will seek relief via a shower, which intensifies the burning, especially if the swimsuit has not been removed. The contaminated swimwear should be immediately discarded, as the trapped sea larvae’s nematocysts activate with the pressure and friction of movement.¹⁵ Seabather’s eruption typically resolves spontaneously within a week, but symptom management can be achieved with topical steroids (triamcinolone 0.1% or clobetasol 0.05%).^15,16 Unlike coral dermatitis, in seabather’s eruption the symptoms are immediate and the location of the eruption coincides with areas covered by the swimsuit.

The Diagnosis: Coral Dermatitis

At 3-week follow-up, the patient demonstrated remarkable improvement in the intensity and size of the erythematous cerebriform plaques following daily application of triamcinolone acetonide cream 0.1% (Figure). The lesion disappeared after several months and did not recur. The delayed presentation of symptoms with a history of incidental coral contact during snorkeling most likely represents the type IV hypersensitivity reaction seen in the diagnosis of coral dermatitis, an extraordinarily rare form of contact dermatitis.¹ Not all coral trigger skin reactions. Species of coral that contain nematocysts in their tentacles (aptly named stinging capsules) are responsible for the sting preceding coral dermatitis, as the nematocysts eject a coiled filament in response to human tactile stimulation that injects toxins into the epidermis.²

Acute, delayed, or chronic cutaneous changes follow envenomation. Acute responses arise immediately to a few hours after initial contact and are considered an irritant contact dermatitis.³ Local tissue histamine release and cascades of cytotoxic reactions often result in the characteristic urticarial or vesiculobullous plaques in addition to necrosis, piloerection, and localized lymphadenopathy.^2-4 Although relatively uncommon, there may be rapid onset of systemic symptoms such as fever, malaise, hives, nausea, or emesis. Cardiopulmonary events, hepatotoxicity, renal failure, or anaphylaxis are rare.² Histopathology of biopsy specimens reveals epidermal spongiosis with microvesicles and papillary dermal edema.^1,5 In comparison, delayed reactions occur within days to weeks and exhibit epidermal parakeratosis, spongiosis, basal layer vacuolization, focal necrosis, lymphocyte exocytosis, and papillary dermal edema with extravasated erythrocytes.1,6 Clinically, it may present as linear rows of erythematous papules with burning and pruritus.⁶ Chronic reactions manifest after months as difficult-to-treat, persistent lichenoid dermatitis occasionally accompanied by granulomatous changes.^1,2,4 Primary prevention measures after initial contact include an acetic acid rinse and cold compression to wash away residual nematocysts in the affected area.^4,7,8 If a rash develops, topical steroids are the mainstay of treatment.^3,8

In tandem with toxic nematocysts, the rigid calcified bodies of coral provide an additional self-defense mechanism against human contact.^2,4 The irregular haphazard nature of coral may catch novice divers off guard and lead to laceration of a mispositioned limb, thereby increasing the risk for secondary infections due to the introduction of calcium carbonate and toxic mucinous deposits at the wound site, warranting antibiotic treatment.^2,4,7 Because tropical locales are home to other natural dangers that inflict disease and mimic early signs of coral dermatitis, reaching an accurate diagnosis can be difficult, particularly for lower limb lesions. In summary, the diagnosis of coral dermatitis can be rendered based on morphology of the lesion and clinical context (exposure to corals and delayed symptoms) as well as response to topical steroids.

The differential diagnosis includes accidental trauma. Variations in impact force and patient skin integrity lead to a number of possible cutaneous manifestations seen in accidental trauma,⁹ which includes contusions resulting from burst capillaries underneath intact skin, abrasions due to the superficial epidermis scuffing away, and lacerations caused by enough force to rip and split the skin, leaving subcutaneous tissue between the intact tissue.^9,10 Typically, the pattern of injury can provide hints to match what object or organism caused the wound.⁹ However, delayed response and worsening symptoms, as seen in coral dermatitis, would be unusual in accidental trauma unless it is complicated by secondary infection (infectious dermatitis), which does not respond to topical steroids and requires antibiotic treatment.

Another differential diagnosis includes cutaneous larva migrans, which infests domesticated and stray animals. For example, hookworm larvae propagate their eggs inside the intestines of their host before fecal-soil transmission in sandy locales.¹¹ Unexpecting beachgoers travel barefoot on this contaminated soil, offering ample opportunity for the parasite to burrow into the upper dermis.^11,12 The clinical presentation includes signs and symptoms of creeping eruption such as pruritic, linear, serpiginous tracks. Topical treatment with thiabendazole requires application 3 times daily for 15 days, which increases the risk for nonadherence, yet this therapy proves advantageous if a patient does not tolerate oral agents due to systemic adverse effects.^11,12 Oral agents (eg, ivermectin, albendazole) offer improved adherence with a single dose^11,13; the cure rate was higher with a single dose of ivermectin 12 mg vs a single dose of albendazole 400 mg.13 The current suggested treatment is ivermectin 200 μg/kg by mouth daily for 1 or 2 days.¹⁴

The incidence of seabather’s eruption (also known as chinkui dermatitis) is highest during the summer season and fluctuates between epidemic and nonepidemic years.^15,16 It occurs sporadically worldwide mostly in tropical climates due to trapping of larvae spawn of sea animals such as crustaceans in swimwear. Initially, it presents as a pruritic and burning sensation after exiting the water, manifesting as a macular, papular, or maculopapular rash on areas covered by the swimsuit.^15,16 The sensation is worse in areas that are tightly banded on the swimsuit, including the waistband and elastic straps.¹⁵ Commonly, the affected individual will seek relief via a shower, which intensifies the burning, especially if the swimsuit has not been removed. The contaminated swimwear should be immediately discarded, as the trapped sea larvae’s nematocysts activate with the pressure and friction of movement.¹⁵ Seabather’s eruption typically resolves spontaneously within a week, but symptom management can be achieved with topical steroids (triamcinolone 0.1% or clobetasol 0.05%).^15,16 Unlike coral dermatitis, in seabather’s eruption the symptoms are immediate and the location of the eruption coincides with areas covered by the swimsuit.

The Diagnosis: Granuloma Annulare

The biopsies revealed palisading granulomatous dermatitis consistent with granuloma annulare (GA). This diagnosis was supported by the clinical presentation and histopathologic findings. Although the pathogenesis of GA is unclear, it is a benign, self-limiting condition. Primarily affected sites include the trunk and forearms. Generalized GA (or GA with ≥10 lesions) may warrant workup for malignancy, as it may represent a paraneoplastic process.¹ Histopathology reveals granulomas comprising a dermal lymphohistiocytic infiltrate as well as central mucin and nuclear debris. There are a few histologic subtypes of GA, including palisading and interstitial, which refer to the distribution of the histiocytic infiltrate.^2,3 This case—with palisading histiocytes lining the collection of necrobiosis and mucin (bottom quiz image)—features palisading GA. Notably, GA exhibits central rather than diffuse mucin.⁴

Erythema gyratum repens is a paraneoplastic arcuate erythema that manifests as erythematous figurate, gyrate, or annular plaques exhibiting a trailing scale. Clinically, erythema gyratum repens spreads rapidly—as quickly as 1 cm/d—and can be extensive (as in this case). Histopathology ruled out this diagnosis in our patient. Nonspecific findings of acanthosis, parakeratosis, and superficial spongiosis can be found in erythema gyratum repens. A superficial and deep perivascular lymphohistiocytic infiltrate may be seen in figurate erythemas (Figure 1).⁵ Unlike GA, this infiltrate does not form granulomas, is more superficial, and does not contain mucin.

Histopathology also can help establish the diagnosis of leprosy and its specific subtype, as leprosy exists on a spectrum from tuberculoid to lepromatous, with a great deal of overlap in between.⁶ Lepromatous leprosy has many cutaneous clinical presentations but typically manifests as erythematous papules or nodules. It is multibacillary, and these mycobacteria form clumps known as globi that can be seen on Fite stain.⁷ In lepromatous leprosy, there is a characteristic dense lymphohistiocytic infiltrate (Figure 2) above which a Grenz zone can be seen.^4,8 There are no well-formed granulomas in lepromatous leprosy, unlike in tuberculoid leprosy, which is paucibacillary and creates a granulomatous response surrounding nerves and adnexal structures.⁶

Mycosis fungoides (MF) is the most common cutaneous lymphoma. There are patch, plaque, and tumor stages of MF, each of which exhibits various histopathologic findings.⁹ In early patch-stage MF, lymphocytes have perinuclear clearing, and the degree of lymphocytic infiltrate is out of proportion to the spongiosis present. Epidermotropism and Pautrier microabscesses often are present in the epidermis (Figure 3). In the plaque stage, there is a denser lymphoid infiltrate in a lichenoid pattern with epidermotropism and Pautrier microabscesses. The tumor stage shows a dense dermal lymphoid infiltrate with more atypia and typically a lack of epidermotropism. Rarely, MF can exhibit a granulomatous variant in which epithelioid histiocytes collect to form granulomas along with atypical lymphocytes.¹⁰

The diagnosis of cutaneous sarcoidosis requires clinicopathologic corroboration. Histopathology demonstrates epithelioid histiocytes forming noncaseating granulomas with little to no lymphocytic infiltrate (Figure 4). There typically is no necrosis or necrobiosis as there is in GA. The diagnosis of sarcoidosis can be challenging histopathologically, and stains should be used to rule out infectious processes.⁴ Asteroid bodies— star-shaped eosinophilic inclusions within giant cells—may be present but are nonspecific for sarcoidosis.¹¹ Schaumann bodies—inclusions of calcifications within giant cells—also may be present and can aid in diagnosis.¹²

The Diagnosis: Granuloma Annulare

The biopsies revealed palisading granulomatous dermatitis consistent with granuloma annulare (GA). This diagnosis was supported by the clinical presentation and histopathologic findings. Although the pathogenesis of GA is unclear, it is a benign, self-limiting condition. Primarily affected sites include the trunk and forearms. Generalized GA (or GA with ≥10 lesions) may warrant workup for malignancy, as it may represent a paraneoplastic process.¹ Histopathology reveals granulomas comprising a dermal lymphohistiocytic infiltrate as well as central mucin and nuclear debris. There are a few histologic subtypes of GA, including palisading and interstitial, which refer to the distribution of the histiocytic infiltrate.^2,3 This case—with palisading histiocytes lining the collection of necrobiosis and mucin (bottom quiz image)—features palisading GA. Notably, GA exhibits central rather than diffuse mucin.⁴

Erythema gyratum repens is a paraneoplastic arcuate erythema that manifests as erythematous figurate, gyrate, or annular plaques exhibiting a trailing scale. Clinically, erythema gyratum repens spreads rapidly—as quickly as 1 cm/d—and can be extensive (as in this case). Histopathology ruled out this diagnosis in our patient. Nonspecific findings of acanthosis, parakeratosis, and superficial spongiosis can be found in erythema gyratum repens. A superficial and deep perivascular lymphohistiocytic infiltrate may be seen in figurate erythemas (Figure 1).⁵ Unlike GA, this infiltrate does not form granulomas, is more superficial, and does not contain mucin.

Histopathology also can help establish the diagnosis of leprosy and its specific subtype, as leprosy exists on a spectrum from tuberculoid to lepromatous, with a great deal of overlap in between.⁶ Lepromatous leprosy has many cutaneous clinical presentations but typically manifests as erythematous papules or nodules. It is multibacillary, and these mycobacteria form clumps known as globi that can be seen on Fite stain.⁷ In lepromatous leprosy, there is a characteristic dense lymphohistiocytic infiltrate (Figure 2) above which a Grenz zone can be seen.^4,8 There are no well-formed granulomas in lepromatous leprosy, unlike in tuberculoid leprosy, which is paucibacillary and creates a granulomatous response surrounding nerves and adnexal structures.⁶

Mycosis fungoides (MF) is the most common cutaneous lymphoma. There are patch, plaque, and tumor stages of MF, each of which exhibits various histopathologic findings.⁹ In early patch-stage MF, lymphocytes have perinuclear clearing, and the degree of lymphocytic infiltrate is out of proportion to the spongiosis present. Epidermotropism and Pautrier microabscesses often are present in the epidermis (Figure 3). In the plaque stage, there is a denser lymphoid infiltrate in a lichenoid pattern with epidermotropism and Pautrier microabscesses. The tumor stage shows a dense dermal lymphoid infiltrate with more atypia and typically a lack of epidermotropism. Rarely, MF can exhibit a granulomatous variant in which epithelioid histiocytes collect to form granulomas along with atypical lymphocytes.¹⁰

The diagnosis of cutaneous sarcoidosis requires clinicopathologic corroboration. Histopathology demonstrates epithelioid histiocytes forming noncaseating granulomas with little to no lymphocytic infiltrate (Figure 4). There typically is no necrosis or necrobiosis as there is in GA. The diagnosis of sarcoidosis can be challenging histopathologically, and stains should be used to rule out infectious processes.⁴ Asteroid bodies— star-shaped eosinophilic inclusions within giant cells—may be present but are nonspecific for sarcoidosis.¹¹ Schaumann bodies—inclusions of calcifications within giant cells—also may be present and can aid in diagnosis.¹²

The Diagnosis: Granuloma Annulare

The biopsies revealed palisading granulomatous dermatitis consistent with granuloma annulare (GA). This diagnosis was supported by the clinical presentation and histopathologic findings. Although the pathogenesis of GA is unclear, it is a benign, self-limiting condition. Primarily affected sites include the trunk and forearms. Generalized GA (or GA with ≥10 lesions) may warrant workup for malignancy, as it may represent a paraneoplastic process.¹ Histopathology reveals granulomas comprising a dermal lymphohistiocytic infiltrate as well as central mucin and nuclear debris. There are a few histologic subtypes of GA, including palisading and interstitial, which refer to the distribution of the histiocytic infiltrate.^2,3 This case—with palisading histiocytes lining the collection of necrobiosis and mucin (bottom quiz image)—features palisading GA. Notably, GA exhibits central rather than diffuse mucin.⁴

Erythema gyratum repens is a paraneoplastic arcuate erythema that manifests as erythematous figurate, gyrate, or annular plaques exhibiting a trailing scale. Clinically, erythema gyratum repens spreads rapidly—as quickly as 1 cm/d—and can be extensive (as in this case). Histopathology ruled out this diagnosis in our patient. Nonspecific findings of acanthosis, parakeratosis, and superficial spongiosis can be found in erythema gyratum repens. A superficial and deep perivascular lymphohistiocytic infiltrate may be seen in figurate erythemas (Figure 1).⁵ Unlike GA, this infiltrate does not form granulomas, is more superficial, and does not contain mucin.

Histopathology also can help establish the diagnosis of leprosy and its specific subtype, as leprosy exists on a spectrum from tuberculoid to lepromatous, with a great deal of overlap in between.⁶ Lepromatous leprosy has many cutaneous clinical presentations but typically manifests as erythematous papules or nodules. It is multibacillary, and these mycobacteria form clumps known as globi that can be seen on Fite stain.⁷ In lepromatous leprosy, there is a characteristic dense lymphohistiocytic infiltrate (Figure 2) above which a Grenz zone can be seen.^4,8 There are no well-formed granulomas in lepromatous leprosy, unlike in tuberculoid leprosy, which is paucibacillary and creates a granulomatous response surrounding nerves and adnexal structures.⁶

Mycosis fungoides (MF) is the most common cutaneous lymphoma. There are patch, plaque, and tumor stages of MF, each of which exhibits various histopathologic findings.⁹ In early patch-stage MF, lymphocytes have perinuclear clearing, and the degree of lymphocytic infiltrate is out of proportion to the spongiosis present. Epidermotropism and Pautrier microabscesses often are present in the epidermis (Figure 3). In the plaque stage, there is a denser lymphoid infiltrate in a lichenoid pattern with epidermotropism and Pautrier microabscesses. The tumor stage shows a dense dermal lymphoid infiltrate with more atypia and typically a lack of epidermotropism. Rarely, MF can exhibit a granulomatous variant in which epithelioid histiocytes collect to form granulomas along with atypical lymphocytes.¹⁰

The diagnosis of cutaneous sarcoidosis requires clinicopathologic corroboration. Histopathology demonstrates epithelioid histiocytes forming noncaseating granulomas with little to no lymphocytic infiltrate (Figure 4). There typically is no necrosis or necrobiosis as there is in GA. The diagnosis of sarcoidosis can be challenging histopathologically, and stains should be used to rule out infectious processes.⁴ Asteroid bodies— star-shaped eosinophilic inclusions within giant cells—may be present but are nonspecific for sarcoidosis.¹¹ Schaumann bodies—inclusions of calcifications within giant cells—also may be present and can aid in diagnosis.¹²