Cutis

The Diagnosis: Syphilis

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

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

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

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

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

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

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

The Diagnosis: Syphilis

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

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

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

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

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

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

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

The Diagnosis: Syphilis

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

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

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

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

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

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

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

To the Editor:

A 67-year-old woman presented to the hospital with painful hands and feet. Two weeks prior, the patient experienced a few days of intermittent purple discoloration of the fingers, followed by black discoloration of the fingers, toes, and nose with notable pain. She reported no illness preceding the presenting symptoms, and there was no progression of symptoms in the days preceding presentation.

The patient had a history of smoking. She had a medical history of chronic obstructive pulmonary disease as well as recurrent non–small cell lung cancer that was treated most recently with a 1-year course of the programmed death-ligand 1 (PD-L1) immune checkpoint inhibitor durvalumab (last treatment was 4 months prior to the current presentation).

Physical examination revealed necrosis of the tips of the second, third, and fourth fingers of the left hand, as well as the tips of the third and fourth fingers of the right hand, progressing to purpura proximally on all involved fingers (Figure, A); scattered purpura and necrotic papules on the toe pads (Figure, B); and a 2- to 3-cm black plaque on the nasal tip. The patient was afebrile.

An embolic and vascular workup was performed. Transthoracic echocardiography was negative for thrombi, ankle brachial indices were within reference range, and computed tomography angiography revealed a few nonocclusive coronary plaques. Conventional angiography was not performed.

Laboratory testing revealed a mildly elevated level of cryofibrinogens (cryocrit, 2.5%); cold agglutinins (1:32); mild monoclonal κ IgG gammopathy (0.1 g/dL); and elevated inflammatory markers (C-reactive protein, 76 mg/L [reference range, 0–10 mg/L]; erythrocyte sedimentation rate, 38 mm/h [reference range, 0–20 mm/h]; fibrinogen, 571 mg/dL [reference range, 150–450 mg/dL]; and ferritin, 394 ng/mL [reference range, 10–180 ng/mL]). Additional laboratory studies were negative or within reference range, including tests of anti-RNA polymerase antibody, rheumatoid factor, antinuclear antibody, anticardiolipin antibody, anti-β₂ glycoprotein antibody, antineutrophil cytoplasmic antibodies (myeloperoxidase and proteinase-3), cryoglobulins, and complement; human immunodeficiency virus and hepatitis B and C virus serologic studies; prothrombin time, partial thromboplastin time, and lupus anticoagulant; and a heparin-induced thrombocytopenia panel.

A skin biopsy adjacent to an area of necrosis on the finger showed thickened walls of dermal vessels, sparse leukocytoclastic debris, and evidence of recanalizing medium-sized vessels. Direct immunofluorescence studies were negative.

Based on the clinical history and histologic findings showing an absence of vasculitis, a diagnosis of acral necrosis associated with the PD-L1 immune checkpoint inhibitor durvalumab—a delayed immune-related event (DIRE)—was favored. The calcium channel blocker amlodipine was started at a dosage of 2.5 mg/d orally. Necrosis of the toes resolved over the course of 1 week; however, necrosis of the fingers remained unchanged. After 1 week of hospitalization, the patient was discharged at her request.

Acral necrosis following immune checkpoint inhibitor therapy has been reported as a rare and recalcitrant immune-related adverse event (AE).^1-4 However, our patient’s symptoms occurred months after treatment was discontinued, which is consistent with a DIRE.⁵ The course of acral necrosis begins with acrocyanosis (a Raynaud disease–like phenomenon) of the fingers that progresses to necrosis. A history of Raynaud disease or other autoimmune disorder generally is absent.¹ Our patient’s history indicated actively smoking at the time of presentation, similar to a case described by Khaddour et al.¹ Similarly, in a case presented by Comont et al,³ the patient also had a history of smoking. In a recent study of acute vascular events associated with immune checkpoint inhibitors, 16 of 31 patients had a history of smoking.⁶

No definitive diagnostic laboratory or pathologic findings are associated with acral necrosis following immune checkpoint inhibitor therapy. Histopathologic analysis does not demonstrate vasculitis or other overt vascular pathology.^2,3

The optimal treatment of immune checkpoint inhibitor–associated digital necrosis is unclear. Corticosteroids and discontinuation of the immune checkpoint inhibitor generally are employed,^1-4 though treatment response has been variable. Other therapies such as calcium channel blockers (as in our case), sympathectomy,¹ epoprostenol, botulinum injection, rituximab,² and alprostadil⁴ have been attempted without clear effect.

We considered a diagnosis of paraneoplastic acral vascular syndrome in our patient, which was ruled out because the syndrome typically occurs in the setting of a worsening underlying malignancy⁷; our patient’s cancer was stable to improved. Thromboangiitis obliterans was ruled out by the absence of a characteristic thrombus on biopsy, the patient’s older age, and involvement of the nose.

We report an unusual case of acral necrosis occurring as a DIRE in response to administration of an immune checkpoint inhibitor. Further description is needed to clarify the diagnostic criteria for and treatment of this rare autoimmune phenomenon.

To the Editor:

A 67-year-old woman presented to the hospital with painful hands and feet. Two weeks prior, the patient experienced a few days of intermittent purple discoloration of the fingers, followed by black discoloration of the fingers, toes, and nose with notable pain. She reported no illness preceding the presenting symptoms, and there was no progression of symptoms in the days preceding presentation.

The patient had a history of smoking. She had a medical history of chronic obstructive pulmonary disease as well as recurrent non–small cell lung cancer that was treated most recently with a 1-year course of the programmed death-ligand 1 (PD-L1) immune checkpoint inhibitor durvalumab (last treatment was 4 months prior to the current presentation).

Physical examination revealed necrosis of the tips of the second, third, and fourth fingers of the left hand, as well as the tips of the third and fourth fingers of the right hand, progressing to purpura proximally on all involved fingers (Figure, A); scattered purpura and necrotic papules on the toe pads (Figure, B); and a 2- to 3-cm black plaque on the nasal tip. The patient was afebrile.

An embolic and vascular workup was performed. Transthoracic echocardiography was negative for thrombi, ankle brachial indices were within reference range, and computed tomography angiography revealed a few nonocclusive coronary plaques. Conventional angiography was not performed.

Laboratory testing revealed a mildly elevated level of cryofibrinogens (cryocrit, 2.5%); cold agglutinins (1:32); mild monoclonal κ IgG gammopathy (0.1 g/dL); and elevated inflammatory markers (C-reactive protein, 76 mg/L [reference range, 0–10 mg/L]; erythrocyte sedimentation rate, 38 mm/h [reference range, 0–20 mm/h]; fibrinogen, 571 mg/dL [reference range, 150–450 mg/dL]; and ferritin, 394 ng/mL [reference range, 10–180 ng/mL]). Additional laboratory studies were negative or within reference range, including tests of anti-RNA polymerase antibody, rheumatoid factor, antinuclear antibody, anticardiolipin antibody, anti-β₂ glycoprotein antibody, antineutrophil cytoplasmic antibodies (myeloperoxidase and proteinase-3), cryoglobulins, and complement; human immunodeficiency virus and hepatitis B and C virus serologic studies; prothrombin time, partial thromboplastin time, and lupus anticoagulant; and a heparin-induced thrombocytopenia panel.

A skin biopsy adjacent to an area of necrosis on the finger showed thickened walls of dermal vessels, sparse leukocytoclastic debris, and evidence of recanalizing medium-sized vessels. Direct immunofluorescence studies were negative.

Based on the clinical history and histologic findings showing an absence of vasculitis, a diagnosis of acral necrosis associated with the PD-L1 immune checkpoint inhibitor durvalumab—a delayed immune-related event (DIRE)—was favored. The calcium channel blocker amlodipine was started at a dosage of 2.5 mg/d orally. Necrosis of the toes resolved over the course of 1 week; however, necrosis of the fingers remained unchanged. After 1 week of hospitalization, the patient was discharged at her request.

Acral necrosis following immune checkpoint inhibitor therapy has been reported as a rare and recalcitrant immune-related adverse event (AE).^1-4 However, our patient’s symptoms occurred months after treatment was discontinued, which is consistent with a DIRE.⁵ The course of acral necrosis begins with acrocyanosis (a Raynaud disease–like phenomenon) of the fingers that progresses to necrosis. A history of Raynaud disease or other autoimmune disorder generally is absent.¹ Our patient’s history indicated actively smoking at the time of presentation, similar to a case described by Khaddour et al.¹ Similarly, in a case presented by Comont et al,³ the patient also had a history of smoking. In a recent study of acute vascular events associated with immune checkpoint inhibitors, 16 of 31 patients had a history of smoking.⁶

No definitive diagnostic laboratory or pathologic findings are associated with acral necrosis following immune checkpoint inhibitor therapy. Histopathologic analysis does not demonstrate vasculitis or other overt vascular pathology.^2,3

The optimal treatment of immune checkpoint inhibitor–associated digital necrosis is unclear. Corticosteroids and discontinuation of the immune checkpoint inhibitor generally are employed,^1-4 though treatment response has been variable. Other therapies such as calcium channel blockers (as in our case), sympathectomy,¹ epoprostenol, botulinum injection, rituximab,² and alprostadil⁴ have been attempted without clear effect.

We considered a diagnosis of paraneoplastic acral vascular syndrome in our patient, which was ruled out because the syndrome typically occurs in the setting of a worsening underlying malignancy⁷; our patient’s cancer was stable to improved. Thromboangiitis obliterans was ruled out by the absence of a characteristic thrombus on biopsy, the patient’s older age, and involvement of the nose.

We report an unusual case of acral necrosis occurring as a DIRE in response to administration of an immune checkpoint inhibitor. Further description is needed to clarify the diagnostic criteria for and treatment of this rare autoimmune phenomenon.

To the Editor:

A 67-year-old woman presented to the hospital with painful hands and feet. Two weeks prior, the patient experienced a few days of intermittent purple discoloration of the fingers, followed by black discoloration of the fingers, toes, and nose with notable pain. She reported no illness preceding the presenting symptoms, and there was no progression of symptoms in the days preceding presentation.

The patient had a history of smoking. She had a medical history of chronic obstructive pulmonary disease as well as recurrent non–small cell lung cancer that was treated most recently with a 1-year course of the programmed death-ligand 1 (PD-L1) immune checkpoint inhibitor durvalumab (last treatment was 4 months prior to the current presentation).

Physical examination revealed necrosis of the tips of the second, third, and fourth fingers of the left hand, as well as the tips of the third and fourth fingers of the right hand, progressing to purpura proximally on all involved fingers (Figure, A); scattered purpura and necrotic papules on the toe pads (Figure, B); and a 2- to 3-cm black plaque on the nasal tip. The patient was afebrile.

An embolic and vascular workup was performed. Transthoracic echocardiography was negative for thrombi, ankle brachial indices were within reference range, and computed tomography angiography revealed a few nonocclusive coronary plaques. Conventional angiography was not performed.

Laboratory testing revealed a mildly elevated level of cryofibrinogens (cryocrit, 2.5%); cold agglutinins (1:32); mild monoclonal κ IgG gammopathy (0.1 g/dL); and elevated inflammatory markers (C-reactive protein, 76 mg/L [reference range, 0–10 mg/L]; erythrocyte sedimentation rate, 38 mm/h [reference range, 0–20 mm/h]; fibrinogen, 571 mg/dL [reference range, 150–450 mg/dL]; and ferritin, 394 ng/mL [reference range, 10–180 ng/mL]). Additional laboratory studies were negative or within reference range, including tests of anti-RNA polymerase antibody, rheumatoid factor, antinuclear antibody, anticardiolipin antibody, anti-β₂ glycoprotein antibody, antineutrophil cytoplasmic antibodies (myeloperoxidase and proteinase-3), cryoglobulins, and complement; human immunodeficiency virus and hepatitis B and C virus serologic studies; prothrombin time, partial thromboplastin time, and lupus anticoagulant; and a heparin-induced thrombocytopenia panel.

A skin biopsy adjacent to an area of necrosis on the finger showed thickened walls of dermal vessels, sparse leukocytoclastic debris, and evidence of recanalizing medium-sized vessels. Direct immunofluorescence studies were negative.

Based on the clinical history and histologic findings showing an absence of vasculitis, a diagnosis of acral necrosis associated with the PD-L1 immune checkpoint inhibitor durvalumab—a delayed immune-related event (DIRE)—was favored. The calcium channel blocker amlodipine was started at a dosage of 2.5 mg/d orally. Necrosis of the toes resolved over the course of 1 week; however, necrosis of the fingers remained unchanged. After 1 week of hospitalization, the patient was discharged at her request.

Acral necrosis following immune checkpoint inhibitor therapy has been reported as a rare and recalcitrant immune-related adverse event (AE).^1-4 However, our patient’s symptoms occurred months after treatment was discontinued, which is consistent with a DIRE.⁵ The course of acral necrosis begins with acrocyanosis (a Raynaud disease–like phenomenon) of the fingers that progresses to necrosis. A history of Raynaud disease or other autoimmune disorder generally is absent.¹ Our patient’s history indicated actively smoking at the time of presentation, similar to a case described by Khaddour et al.¹ Similarly, in a case presented by Comont et al,³ the patient also had a history of smoking. In a recent study of acute vascular events associated with immune checkpoint inhibitors, 16 of 31 patients had a history of smoking.⁶

No definitive diagnostic laboratory or pathologic findings are associated with acral necrosis following immune checkpoint inhibitor therapy. Histopathologic analysis does not demonstrate vasculitis or other overt vascular pathology.^2,3

The optimal treatment of immune checkpoint inhibitor–associated digital necrosis is unclear. Corticosteroids and discontinuation of the immune checkpoint inhibitor generally are employed,^1-4 though treatment response has been variable. Other therapies such as calcium channel blockers (as in our case), sympathectomy,¹ epoprostenol, botulinum injection, rituximab,² and alprostadil⁴ have been attempted without clear effect.

We considered a diagnosis of paraneoplastic acral vascular syndrome in our patient, which was ruled out because the syndrome typically occurs in the setting of a worsening underlying malignancy⁷; our patient’s cancer was stable to improved. Thromboangiitis obliterans was ruled out by the absence of a characteristic thrombus on biopsy, the patient’s older age, and involvement of the nose.

We report an unusual case of acral necrosis occurring as a DIRE in response to administration of an immune checkpoint inhibitor. Further description is needed to clarify the diagnostic criteria for and treatment of this rare autoimmune phenomenon.

To the Editor:

Programmed cell death protein 1 (PD-1) inhibitors have been widely used in the treatment of various cancers. Programmed cell death-ligand 1 (PD-L1) and programmed cell death-ligand 2 located on cancer cells will bind to PD-1 receptors on T cells and suppress them, which will prevent cancer cell destruction. Programmed cell death protein 1 inhibitors block the binding of PD-L1 to cancer cells, which then prevents T-cell immunosuppression.¹ However, cutaneous adverse effects have been associated with PD-1 inhibitors. Dermatitis associated with PD-1 inhibitor therapy occurs more frequently in patients with cutaneous tumors such as melanoma compared to those with head and neck cancers.² Curry et al¹ reported that treatment with an immune checkpoint blockade can lead to immune-related adverse effects, most commonly affecting the gastrointestinal tract, liver, and skin. The same report cited dermatologic toxicity as an adverse effect in approximately 39% of patients treated with anti–PD-1 and approximately 17% of anti–PD-L1.¹ The 4 main categories of dermatologic toxicities to immunotherapies in general include inflammatory disorders, immunobullous disorders, alterations of keratinocytes, and alteration of melanocytes. The most common adverse effects from the use of the PD-1 inhibitor nivolumab were skin rashes, not otherwise specified (14%–20%), pruritus (13%–18%), and vitiligo (~8%).¹ Of the cutaneous dermatitic reactions to PD-1 and PD-L1 inhibitors that were biopsied, the 2 most common were lichenoid dermatitis and spongiotic dermatitis.² Seldomly, there have been reports of keratoacanthomas (KAs) in association with anti–PD-1 therapy.³

A KA is a common skin tumor that appears most frequently as a solitary lesion and is thought to arise from the hair follicle.⁴ It resembles squamous cell carcinoma and commonly regresses within months without intervention. Exposure to UV light is a known risk factor for the development of KAs.

Eruptive KAs have been found in association with 10 cases of various cancers treated with the PD-1 inhibitors pembrolizumab and nivolumab.³ Multiple lesions on photodistributed areas of the body were reported in all 10 cases. Various treatments were used in these 10 cases—doxycycline and niacinamide, electrodesiccation and curettage, clobetasol ointment and/or intralesional triamcinolone, cryotherapy, imiquimod, or no treatment—as well as the cessation of PD-1 inhibitor therapy, with 4 cases continuing therapy and 6 cases discontinuing therapy. Nine cases regressed by 6 months; electrodesiccation and curettage of the lesions was used in the tenth case.³ We report a case of eruptive KA after 1 cycle of nivolumab therapy for metastatic melanoma.

A 79-year-old woman with stage III melanoma presented to her dermatologist after developing generalized pruritic lichenoid eruptions involving the torso, arms, and legs, as well as erosions on the lips, buccal mucosa, and palate 1 month after starting nivolumab therapy. The patient initially presented to dermatology with an irregularly shaped lesion on the left upper back 3 months prior. Biopsy results at that time revealed a diagnosis of malignant melanoma, lentigo maligna type. The lesion was 1.5-mm thick and classified as Clark level IV with a mitotic count of 6 per mm². Molecular genetic studies showed expression of PD-L1 and no expression of c-KIT. The patient underwent wide local excision, and a sentinel lymph node biopsy was positive. Positron emission tomography did not show any hypermetabolic lesions, and magnetic resonance imaging did not indicate brain metastasis. The patient underwent an axillary dissection, which did not show any residual melanoma. She was started on adjuvant immunotherapy with intravenous nivolumab 480 mg monthly and developed pruritic crusted lesions on the arms, legs, and torso 1 month later, which prompted follow-up to dermatology.

At the current presentation 4 months after the onset of lesions, physical examination revealed lichenoid patches with serous crusting that were concentrated on the torso but also affected the arms and legs. She developed erosions on the upper and lower lips, buccal mucosa, and hard and soft palates, as well as painful, erythematous, dome-shaped papules and nodules on the legs (Figure 1). Her oncologist previously had initiated treatment at the onset of the lesions with clobetasol cream and valacyclovir for the lesions, but the patient showed no improvement.

Four months after the onset of the lesions, the patient was re-referred to her dermatologist, and a biopsy was performed on the left lower leg that showed squamous cell carcinoma, KA type. Additionally, flat erythematous patches were seen on the legs that were consistent with a lichenoid drug eruption. Two weeks later, she was started on halobetasol propionate ointment 0.05% for treatment of the KAs. At 2-week follow-up, 5 months after the onset of the lesions, the patient showed no signs of improvement. An oral prednisone taper of 60 mg for 3 days, 40 mg for 3 days, and then 20 mg daily for a total of 4 weeks was started to treat the lichenoid dermatitis and eruptive KAs. At the next follow-up 6.5 months following the first eruptive KAs, she was no longer using topical or oral steroids, she did not have any new eruptive KAs, and old lesions showed regression (Figure 2). The patient still experienced postinflammatory erythema and hyperpigmentation at the location of the KAs but showed improvement of the lichenoid drug eruption.

We describe a case of eruptive KAs after use of a PD-1 inhibitor for treatment of melanoma. Our patient developed eruptive KAs after only 1 nivolumab treatment. Another report described onset of eruptive KAs after 1 month of nivolumab infusions.³ The KAs experienced by our patient took 6.5 months to regress, which is unusual compared to other case reports in which the KAs self-resolved within a few months, though one other case described lesions that persisted for 6 months.³

Our patient was treated with topical steroids and an oral steroid taper for the concomitant lichenoid drug eruption. It is unknown if the steroids affected the course of the KAs or if they spontaneously regressed on their own. Freites-Martinez et al⁵ described that regression of KAs may be related to an immune response, but corticosteroids are inherently immunosuppressive. They hypothesized that corticosteroids help to temper the heightened immune response of eruptive KAs.⁵

Our patient had oral ulcers, which may have been indicative of an oral lichenoid drug eruption, as well as skin lesions representative of a cutaneous lichenoid drug eruption. This is a favorable reaction, as lichenoid dermatitis is thought to represent successful PD-1 inhibition and therefore a better response to oncologic therapies.² Comorbid lichenoid drug eruption lesions and eruptive KAs may be suggestive of increased T-cell activity,^2,6,7 though some prior case studies have reported eruptive KAs in isolation.³

Discontinuation of immunotherapy due to development of eruptive KAs presents a challenge in the treatment of underlying malignancies such as melanoma. Immunotherapy was discontinued in 7 of 11 cases due to these cutaneous reactions.³ Similarly, our patient underwent only 1 cycle of immunotherapy before developing eruptive KAs and discontinuing PD-1 inhibitor therapy. If we are better able to treat eruptive KAs, then patients can remain on immunotherapy to treat underlying malignancies. Crow et al⁸ showed improvement in lesions when 3 patients with eruptive KAs were treated with hydroxychloroquine; the Goeckerman regimen consisting of steroids, UVB phototherapy, and crude coal tar; and Unna boots with zinc oxide and compression stockings. The above may be added to a list of possible treatments to consider for hastening the regression of eruptive KAs.

Our patient’s clinical course was similar to reports on the regressive nature of eruptive KAs within 6 months after initial eruption. Although it is likely that KAs will regress on their own, treatment modalities that speed up recovery are a future source for research.

To the Editor:

Programmed cell death protein 1 (PD-1) inhibitors have been widely used in the treatment of various cancers. Programmed cell death-ligand 1 (PD-L1) and programmed cell death-ligand 2 located on cancer cells will bind to PD-1 receptors on T cells and suppress them, which will prevent cancer cell destruction. Programmed cell death protein 1 inhibitors block the binding of PD-L1 to cancer cells, which then prevents T-cell immunosuppression.¹ However, cutaneous adverse effects have been associated with PD-1 inhibitors. Dermatitis associated with PD-1 inhibitor therapy occurs more frequently in patients with cutaneous tumors such as melanoma compared to those with head and neck cancers.² Curry et al¹ reported that treatment with an immune checkpoint blockade can lead to immune-related adverse effects, most commonly affecting the gastrointestinal tract, liver, and skin. The same report cited dermatologic toxicity as an adverse effect in approximately 39% of patients treated with anti–PD-1 and approximately 17% of anti–PD-L1.¹ The 4 main categories of dermatologic toxicities to immunotherapies in general include inflammatory disorders, immunobullous disorders, alterations of keratinocytes, and alteration of melanocytes. The most common adverse effects from the use of the PD-1 inhibitor nivolumab were skin rashes, not otherwise specified (14%–20%), pruritus (13%–18%), and vitiligo (~8%).¹ Of the cutaneous dermatitic reactions to PD-1 and PD-L1 inhibitors that were biopsied, the 2 most common were lichenoid dermatitis and spongiotic dermatitis.² Seldomly, there have been reports of keratoacanthomas (KAs) in association with anti–PD-1 therapy.³

A KA is a common skin tumor that appears most frequently as a solitary lesion and is thought to arise from the hair follicle.⁴ It resembles squamous cell carcinoma and commonly regresses within months without intervention. Exposure to UV light is a known risk factor for the development of KAs.

Eruptive KAs have been found in association with 10 cases of various cancers treated with the PD-1 inhibitors pembrolizumab and nivolumab.³ Multiple lesions on photodistributed areas of the body were reported in all 10 cases. Various treatments were used in these 10 cases—doxycycline and niacinamide, electrodesiccation and curettage, clobetasol ointment and/or intralesional triamcinolone, cryotherapy, imiquimod, or no treatment—as well as the cessation of PD-1 inhibitor therapy, with 4 cases continuing therapy and 6 cases discontinuing therapy. Nine cases regressed by 6 months; electrodesiccation and curettage of the lesions was used in the tenth case.³ We report a case of eruptive KA after 1 cycle of nivolumab therapy for metastatic melanoma.

A 79-year-old woman with stage III melanoma presented to her dermatologist after developing generalized pruritic lichenoid eruptions involving the torso, arms, and legs, as well as erosions on the lips, buccal mucosa, and palate 1 month after starting nivolumab therapy. The patient initially presented to dermatology with an irregularly shaped lesion on the left upper back 3 months prior. Biopsy results at that time revealed a diagnosis of malignant melanoma, lentigo maligna type. The lesion was 1.5-mm thick and classified as Clark level IV with a mitotic count of 6 per mm². Molecular genetic studies showed expression of PD-L1 and no expression of c-KIT. The patient underwent wide local excision, and a sentinel lymph node biopsy was positive. Positron emission tomography did not show any hypermetabolic lesions, and magnetic resonance imaging did not indicate brain metastasis. The patient underwent an axillary dissection, which did not show any residual melanoma. She was started on adjuvant immunotherapy with intravenous nivolumab 480 mg monthly and developed pruritic crusted lesions on the arms, legs, and torso 1 month later, which prompted follow-up to dermatology.

At the current presentation 4 months after the onset of lesions, physical examination revealed lichenoid patches with serous crusting that were concentrated on the torso but also affected the arms and legs. She developed erosions on the upper and lower lips, buccal mucosa, and hard and soft palates, as well as painful, erythematous, dome-shaped papules and nodules on the legs (Figure 1). Her oncologist previously had initiated treatment at the onset of the lesions with clobetasol cream and valacyclovir for the lesions, but the patient showed no improvement.

Four months after the onset of the lesions, the patient was re-referred to her dermatologist, and a biopsy was performed on the left lower leg that showed squamous cell carcinoma, KA type. Additionally, flat erythematous patches were seen on the legs that were consistent with a lichenoid drug eruption. Two weeks later, she was started on halobetasol propionate ointment 0.05% for treatment of the KAs. At 2-week follow-up, 5 months after the onset of the lesions, the patient showed no signs of improvement. An oral prednisone taper of 60 mg for 3 days, 40 mg for 3 days, and then 20 mg daily for a total of 4 weeks was started to treat the lichenoid dermatitis and eruptive KAs. At the next follow-up 6.5 months following the first eruptive KAs, she was no longer using topical or oral steroids, she did not have any new eruptive KAs, and old lesions showed regression (Figure 2). The patient still experienced postinflammatory erythema and hyperpigmentation at the location of the KAs but showed improvement of the lichenoid drug eruption.

We describe a case of eruptive KAs after use of a PD-1 inhibitor for treatment of melanoma. Our patient developed eruptive KAs after only 1 nivolumab treatment. Another report described onset of eruptive KAs after 1 month of nivolumab infusions.³ The KAs experienced by our patient took 6.5 months to regress, which is unusual compared to other case reports in which the KAs self-resolved within a few months, though one other case described lesions that persisted for 6 months.³

Our patient was treated with topical steroids and an oral steroid taper for the concomitant lichenoid drug eruption. It is unknown if the steroids affected the course of the KAs or if they spontaneously regressed on their own. Freites-Martinez et al⁵ described that regression of KAs may be related to an immune response, but corticosteroids are inherently immunosuppressive. They hypothesized that corticosteroids help to temper the heightened immune response of eruptive KAs.⁵

Our patient had oral ulcers, which may have been indicative of an oral lichenoid drug eruption, as well as skin lesions representative of a cutaneous lichenoid drug eruption. This is a favorable reaction, as lichenoid dermatitis is thought to represent successful PD-1 inhibition and therefore a better response to oncologic therapies.² Comorbid lichenoid drug eruption lesions and eruptive KAs may be suggestive of increased T-cell activity,^2,6,7 though some prior case studies have reported eruptive KAs in isolation.³

Discontinuation of immunotherapy due to development of eruptive KAs presents a challenge in the treatment of underlying malignancies such as melanoma. Immunotherapy was discontinued in 7 of 11 cases due to these cutaneous reactions.³ Similarly, our patient underwent only 1 cycle of immunotherapy before developing eruptive KAs and discontinuing PD-1 inhibitor therapy. If we are better able to treat eruptive KAs, then patients can remain on immunotherapy to treat underlying malignancies. Crow et al⁸ showed improvement in lesions when 3 patients with eruptive KAs were treated with hydroxychloroquine; the Goeckerman regimen consisting of steroids, UVB phototherapy, and crude coal tar; and Unna boots with zinc oxide and compression stockings. The above may be added to a list of possible treatments to consider for hastening the regression of eruptive KAs.

Our patient’s clinical course was similar to reports on the regressive nature of eruptive KAs within 6 months after initial eruption. Although it is likely that KAs will regress on their own, treatment modalities that speed up recovery are a future source for research.

To the Editor:

Programmed cell death protein 1 (PD-1) inhibitors have been widely used in the treatment of various cancers. Programmed cell death-ligand 1 (PD-L1) and programmed cell death-ligand 2 located on cancer cells will bind to PD-1 receptors on T cells and suppress them, which will prevent cancer cell destruction. Programmed cell death protein 1 inhibitors block the binding of PD-L1 to cancer cells, which then prevents T-cell immunosuppression.¹ However, cutaneous adverse effects have been associated with PD-1 inhibitors. Dermatitis associated with PD-1 inhibitor therapy occurs more frequently in patients with cutaneous tumors such as melanoma compared to those with head and neck cancers.² Curry et al¹ reported that treatment with an immune checkpoint blockade can lead to immune-related adverse effects, most commonly affecting the gastrointestinal tract, liver, and skin. The same report cited dermatologic toxicity as an adverse effect in approximately 39% of patients treated with anti–PD-1 and approximately 17% of anti–PD-L1.¹ The 4 main categories of dermatologic toxicities to immunotherapies in general include inflammatory disorders, immunobullous disorders, alterations of keratinocytes, and alteration of melanocytes. The most common adverse effects from the use of the PD-1 inhibitor nivolumab were skin rashes, not otherwise specified (14%–20%), pruritus (13%–18%), and vitiligo (~8%).¹ Of the cutaneous dermatitic reactions to PD-1 and PD-L1 inhibitors that were biopsied, the 2 most common were lichenoid dermatitis and spongiotic dermatitis.² Seldomly, there have been reports of keratoacanthomas (KAs) in association with anti–PD-1 therapy.³

A KA is a common skin tumor that appears most frequently as a solitary lesion and is thought to arise from the hair follicle.⁴ It resembles squamous cell carcinoma and commonly regresses within months without intervention. Exposure to UV light is a known risk factor for the development of KAs.

Eruptive KAs have been found in association with 10 cases of various cancers treated with the PD-1 inhibitors pembrolizumab and nivolumab.³ Multiple lesions on photodistributed areas of the body were reported in all 10 cases. Various treatments were used in these 10 cases—doxycycline and niacinamide, electrodesiccation and curettage, clobetasol ointment and/or intralesional triamcinolone, cryotherapy, imiquimod, or no treatment—as well as the cessation of PD-1 inhibitor therapy, with 4 cases continuing therapy and 6 cases discontinuing therapy. Nine cases regressed by 6 months; electrodesiccation and curettage of the lesions was used in the tenth case.³ We report a case of eruptive KA after 1 cycle of nivolumab therapy for metastatic melanoma.

A 79-year-old woman with stage III melanoma presented to her dermatologist after developing generalized pruritic lichenoid eruptions involving the torso, arms, and legs, as well as erosions on the lips, buccal mucosa, and palate 1 month after starting nivolumab therapy. The patient initially presented to dermatology with an irregularly shaped lesion on the left upper back 3 months prior. Biopsy results at that time revealed a diagnosis of malignant melanoma, lentigo maligna type. The lesion was 1.5-mm thick and classified as Clark level IV with a mitotic count of 6 per mm². Molecular genetic studies showed expression of PD-L1 and no expression of c-KIT. The patient underwent wide local excision, and a sentinel lymph node biopsy was positive. Positron emission tomography did not show any hypermetabolic lesions, and magnetic resonance imaging did not indicate brain metastasis. The patient underwent an axillary dissection, which did not show any residual melanoma. She was started on adjuvant immunotherapy with intravenous nivolumab 480 mg monthly and developed pruritic crusted lesions on the arms, legs, and torso 1 month later, which prompted follow-up to dermatology.

At the current presentation 4 months after the onset of lesions, physical examination revealed lichenoid patches with serous crusting that were concentrated on the torso but also affected the arms and legs. She developed erosions on the upper and lower lips, buccal mucosa, and hard and soft palates, as well as painful, erythematous, dome-shaped papules and nodules on the legs (Figure 1). Her oncologist previously had initiated treatment at the onset of the lesions with clobetasol cream and valacyclovir for the lesions, but the patient showed no improvement.

Four months after the onset of the lesions, the patient was re-referred to her dermatologist, and a biopsy was performed on the left lower leg that showed squamous cell carcinoma, KA type. Additionally, flat erythematous patches were seen on the legs that were consistent with a lichenoid drug eruption. Two weeks later, she was started on halobetasol propionate ointment 0.05% for treatment of the KAs. At 2-week follow-up, 5 months after the onset of the lesions, the patient showed no signs of improvement. An oral prednisone taper of 60 mg for 3 days, 40 mg for 3 days, and then 20 mg daily for a total of 4 weeks was started to treat the lichenoid dermatitis and eruptive KAs. At the next follow-up 6.5 months following the first eruptive KAs, she was no longer using topical or oral steroids, she did not have any new eruptive KAs, and old lesions showed regression (Figure 2). The patient still experienced postinflammatory erythema and hyperpigmentation at the location of the KAs but showed improvement of the lichenoid drug eruption.

We describe a case of eruptive KAs after use of a PD-1 inhibitor for treatment of melanoma. Our patient developed eruptive KAs after only 1 nivolumab treatment. Another report described onset of eruptive KAs after 1 month of nivolumab infusions.³ The KAs experienced by our patient took 6.5 months to regress, which is unusual compared to other case reports in which the KAs self-resolved within a few months, though one other case described lesions that persisted for 6 months.³

Our patient was treated with topical steroids and an oral steroid taper for the concomitant lichenoid drug eruption. It is unknown if the steroids affected the course of the KAs or if they spontaneously regressed on their own. Freites-Martinez et al⁵ described that regression of KAs may be related to an immune response, but corticosteroids are inherently immunosuppressive. They hypothesized that corticosteroids help to temper the heightened immune response of eruptive KAs.⁵

Our patient had oral ulcers, which may have been indicative of an oral lichenoid drug eruption, as well as skin lesions representative of a cutaneous lichenoid drug eruption. This is a favorable reaction, as lichenoid dermatitis is thought to represent successful PD-1 inhibition and therefore a better response to oncologic therapies.² Comorbid lichenoid drug eruption lesions and eruptive KAs may be suggestive of increased T-cell activity,^2,6,7 though some prior case studies have reported eruptive KAs in isolation.³

Discontinuation of immunotherapy due to development of eruptive KAs presents a challenge in the treatment of underlying malignancies such as melanoma. Immunotherapy was discontinued in 7 of 11 cases due to these cutaneous reactions.³ Similarly, our patient underwent only 1 cycle of immunotherapy before developing eruptive KAs and discontinuing PD-1 inhibitor therapy. If we are better able to treat eruptive KAs, then patients can remain on immunotherapy to treat underlying malignancies. Crow et al⁸ showed improvement in lesions when 3 patients with eruptive KAs were treated with hydroxychloroquine; the Goeckerman regimen consisting of steroids, UVB phototherapy, and crude coal tar; and Unna boots with zinc oxide and compression stockings. The above may be added to a list of possible treatments to consider for hastening the regression of eruptive KAs.

Our patient’s clinical course was similar to reports on the regressive nature of eruptive KAs within 6 months after initial eruption. Although it is likely that KAs will regress on their own, treatment modalities that speed up recovery are a future source for research.

Inpatient dermatology consultation services are becoming increasingly prevalent in hospital institutions.^1-3 Although often underutilized as a consulting service, dermatology-related admissions cost hundreds of millions of dollars for the health care system.^1,2 Misdiagnosis, prolonged hospital stays, and incorrect treatment are common results of lack of involvement by a skin expert.^1-3 The importance of consultative inpatient dermatology cannot be understated. Accreditation Council for Graduate Medical Education requirements for proficiency in dermatology residency include exposure to inpatient dermatology, and it is our duty as residents to aid our colleagues in the management and treatment of cutaneous disease.

Although exposure to inpatient dermatology varies across residency programs, nearly every dermatology resident is bound to perform a consultation and be involved in the care of a hospitalized patient. At our program at the University of Utah (Salt Lake City), we have robust inpatient exposure, and after numerous hours spent on the forefront of inpatient dermatology, I have accrued a list of specific tips and techniques that have aided me as a resident clinician.

Pre-Rounding More Thoroughly

When I started as a postgraduate year 2 (PGY-2) on the inpatient dermatology rotation, I found myself perplexed. I had learned how to round in internal medicine but was unaccustomed to the nuances of specialty rounds. My list included calciphylaxis, small vessel vasculitis, cellulitis, stasis dermatitis, toxic epidermal necrolysis, and atypical mycobacterial infection. The first few days of service were undeniably difficult due to the daily consultations, complexity of admitted patients, and need for efficiency. I sometimes overlooked important laboratory test results, medication changes, and interdisciplinary discussions that prolonged rounding. As dermatologists, we are responsible for the largest organ of the body, and it is important to approach patients in a comprehensive manner. Pre-rounding should include reviewing interdisciplinary notes, laboratory values/results, and medications, and performing a focused skin examination with a review of systems during the encounter. Importantly, most electronic medical record systems offer an automated rounding sheet. In Epic (Epic Systems Corporation), I would use the bone marrow transplant rounding sheet, which includes laboratory test results, vitals, and medications. After printing out the rounding sheet, I would note important updates for each patient. Although pre-rounding and chart review requires time and effort, it aided me in providing elevated patient care and becoming more efficient during rounds. Over time I have come to strongly appreciate the term dermatology hospitalist. Cutaneous manifestations of systemic disease require thoughtful consideration and workup.

New Patient Consultations: Must-Ask Questions

Holding the university inpatient pager can be stressful. At the University of Utah, we often carry 5 to 10 patients on our list and receive 3 to 4 new consultations a day, sometimes right before 5 pm. When receiving new consultations, it is important to obtain the whole story from the requesting provider. Some of the questions may seem obvious, but I am frequently reminded of the inefficiencies I encountered as a first-year dermatology resident. Remember to always be kind to your consulting colleagues. Dermatology is a difficult discipline, and describing rashes is no easy task. Here is my systematic approach to questions that should be asked of the requesting provider during each new patient consultation:

• What is the patient’s name, room number, and medical record number?
• Is this patient getting admitted or admitted currently?
• Is the rash the reason for admission? (This can greatly help with triaging the urgency of evaluation.)
• Is the rash painful?
• Is this patient ill?
• How would you describe the rash?

When evaluating new patients, it is crucial to remember the morphology camps. Formulating a differential diagnosis on a complex patient can be difficult; however, remembering the morphology camps of acneiform, dermal, eczematous, erythematous, subcutaneous, vasculitic, vasculopathic, and vesiculobullous lesions can be extremely helpful. Additionally, it is crucial to perform a thorough and complete skin examination on every patient. When emphasizing the importance of this, I often am reminded of a humbling moment early in my training. Our team was consulted on a patient with cellulitis and stasis dermatitis. It was a busy day, and my examination was quick and focused on the lower and upper extremities, chest, and back. The patient improved from a cutaneous standpoint and was discharged. At follow-up the next week, one of my attending providers biopsied an atypical macule on the retroauricular region, which was found to be consistent with a stage 1A melanoma. Even on the longest and most tiring hospital days, it is important to perform a full-body skin examination on each patient. You may end up saving a life.

An Organized Toolbox: What to Carry

Similar to our ophthalmology colleagues who are seen carrying around a suitcase in the hospital, I highly recommend some form of a toolbox or bag for performing inpatient biopsies (Table). Carrying around an organized bag, albeit bulky and unfashionable, has saved me numerous trips back to clinic for unexpected complications including fixing leaky vessels, closing stubborn ulcers, and coordinating sedated biopsies in the operating room.

Final Thoughts

As I near the completion of my residency journey, I hope these tips will aid budding and current dermatology residents at excelling as dermatology hospitalists during inpatient rotations. Dermatologists can make a profound impact on a variety of patients, especially when treating hospitalized patients on the clinical forefront. Our role extends beyond the skin, as cutaneous manifestations of internal disease are not uncommon.

Inpatient dermatology consultation services are becoming increasingly prevalent in hospital institutions.^1-3 Although often underutilized as a consulting service, dermatology-related admissions cost hundreds of millions of dollars for the health care system.^1,2 Misdiagnosis, prolonged hospital stays, and incorrect treatment are common results of lack of involvement by a skin expert.^1-3 The importance of consultative inpatient dermatology cannot be understated. Accreditation Council for Graduate Medical Education requirements for proficiency in dermatology residency include exposure to inpatient dermatology, and it is our duty as residents to aid our colleagues in the management and treatment of cutaneous disease.

Although exposure to inpatient dermatology varies across residency programs, nearly every dermatology resident is bound to perform a consultation and be involved in the care of a hospitalized patient. At our program at the University of Utah (Salt Lake City), we have robust inpatient exposure, and after numerous hours spent on the forefront of inpatient dermatology, I have accrued a list of specific tips and techniques that have aided me as a resident clinician.

Pre-Rounding More Thoroughly

When I started as a postgraduate year 2 (PGY-2) on the inpatient dermatology rotation, I found myself perplexed. I had learned how to round in internal medicine but was unaccustomed to the nuances of specialty rounds. My list included calciphylaxis, small vessel vasculitis, cellulitis, stasis dermatitis, toxic epidermal necrolysis, and atypical mycobacterial infection. The first few days of service were undeniably difficult due to the daily consultations, complexity of admitted patients, and need for efficiency. I sometimes overlooked important laboratory test results, medication changes, and interdisciplinary discussions that prolonged rounding. As dermatologists, we are responsible for the largest organ of the body, and it is important to approach patients in a comprehensive manner. Pre-rounding should include reviewing interdisciplinary notes, laboratory values/results, and medications, and performing a focused skin examination with a review of systems during the encounter. Importantly, most electronic medical record systems offer an automated rounding sheet. In Epic (Epic Systems Corporation), I would use the bone marrow transplant rounding sheet, which includes laboratory test results, vitals, and medications. After printing out the rounding sheet, I would note important updates for each patient. Although pre-rounding and chart review requires time and effort, it aided me in providing elevated patient care and becoming more efficient during rounds. Over time I have come to strongly appreciate the term dermatology hospitalist. Cutaneous manifestations of systemic disease require thoughtful consideration and workup.

New Patient Consultations: Must-Ask Questions

Holding the university inpatient pager can be stressful. At the University of Utah, we often carry 5 to 10 patients on our list and receive 3 to 4 new consultations a day, sometimes right before 5 pm. When receiving new consultations, it is important to obtain the whole story from the requesting provider. Some of the questions may seem obvious, but I am frequently reminded of the inefficiencies I encountered as a first-year dermatology resident. Remember to always be kind to your consulting colleagues. Dermatology is a difficult discipline, and describing rashes is no easy task. Here is my systematic approach to questions that should be asked of the requesting provider during each new patient consultation:

• What is the patient’s name, room number, and medical record number?
• Is this patient getting admitted or admitted currently?
• Is the rash the reason for admission? (This can greatly help with triaging the urgency of evaluation.)
• Is the rash painful?
• Is this patient ill?
• How would you describe the rash?

When evaluating new patients, it is crucial to remember the morphology camps. Formulating a differential diagnosis on a complex patient can be difficult; however, remembering the morphology camps of acneiform, dermal, eczematous, erythematous, subcutaneous, vasculitic, vasculopathic, and vesiculobullous lesions can be extremely helpful. Additionally, it is crucial to perform a thorough and complete skin examination on every patient. When emphasizing the importance of this, I often am reminded of a humbling moment early in my training. Our team was consulted on a patient with cellulitis and stasis dermatitis. It was a busy day, and my examination was quick and focused on the lower and upper extremities, chest, and back. The patient improved from a cutaneous standpoint and was discharged. At follow-up the next week, one of my attending providers biopsied an atypical macule on the retroauricular region, which was found to be consistent with a stage 1A melanoma. Even on the longest and most tiring hospital days, it is important to perform a full-body skin examination on each patient. You may end up saving a life.

An Organized Toolbox: What to Carry

Similar to our ophthalmology colleagues who are seen carrying around a suitcase in the hospital, I highly recommend some form of a toolbox or bag for performing inpatient biopsies (Table). Carrying around an organized bag, albeit bulky and unfashionable, has saved me numerous trips back to clinic for unexpected complications including fixing leaky vessels, closing stubborn ulcers, and coordinating sedated biopsies in the operating room.

Final Thoughts

As I near the completion of my residency journey, I hope these tips will aid budding and current dermatology residents at excelling as dermatology hospitalists during inpatient rotations. Dermatologists can make a profound impact on a variety of patients, especially when treating hospitalized patients on the clinical forefront. Our role extends beyond the skin, as cutaneous manifestations of internal disease are not uncommon.

Inpatient dermatology consultation services are becoming increasingly prevalent in hospital institutions.^1-3 Although often underutilized as a consulting service, dermatology-related admissions cost hundreds of millions of dollars for the health care system.^1,2 Misdiagnosis, prolonged hospital stays, and incorrect treatment are common results of lack of involvement by a skin expert.^1-3 The importance of consultative inpatient dermatology cannot be understated. Accreditation Council for Graduate Medical Education requirements for proficiency in dermatology residency include exposure to inpatient dermatology, and it is our duty as residents to aid our colleagues in the management and treatment of cutaneous disease.

Although exposure to inpatient dermatology varies across residency programs, nearly every dermatology resident is bound to perform a consultation and be involved in the care of a hospitalized patient. At our program at the University of Utah (Salt Lake City), we have robust inpatient exposure, and after numerous hours spent on the forefront of inpatient dermatology, I have accrued a list of specific tips and techniques that have aided me as a resident clinician.

Pre-Rounding More Thoroughly

When I started as a postgraduate year 2 (PGY-2) on the inpatient dermatology rotation, I found myself perplexed. I had learned how to round in internal medicine but was unaccustomed to the nuances of specialty rounds. My list included calciphylaxis, small vessel vasculitis, cellulitis, stasis dermatitis, toxic epidermal necrolysis, and atypical mycobacterial infection. The first few days of service were undeniably difficult due to the daily consultations, complexity of admitted patients, and need for efficiency. I sometimes overlooked important laboratory test results, medication changes, and interdisciplinary discussions that prolonged rounding. As dermatologists, we are responsible for the largest organ of the body, and it is important to approach patients in a comprehensive manner. Pre-rounding should include reviewing interdisciplinary notes, laboratory values/results, and medications, and performing a focused skin examination with a review of systems during the encounter. Importantly, most electronic medical record systems offer an automated rounding sheet. In Epic (Epic Systems Corporation), I would use the bone marrow transplant rounding sheet, which includes laboratory test results, vitals, and medications. After printing out the rounding sheet, I would note important updates for each patient. Although pre-rounding and chart review requires time and effort, it aided me in providing elevated patient care and becoming more efficient during rounds. Over time I have come to strongly appreciate the term dermatology hospitalist. Cutaneous manifestations of systemic disease require thoughtful consideration and workup.

New Patient Consultations: Must-Ask Questions

Holding the university inpatient pager can be stressful. At the University of Utah, we often carry 5 to 10 patients on our list and receive 3 to 4 new consultations a day, sometimes right before 5 pm. When receiving new consultations, it is important to obtain the whole story from the requesting provider. Some of the questions may seem obvious, but I am frequently reminded of the inefficiencies I encountered as a first-year dermatology resident. Remember to always be kind to your consulting colleagues. Dermatology is a difficult discipline, and describing rashes is no easy task. Here is my systematic approach to questions that should be asked of the requesting provider during each new patient consultation:

• What is the patient’s name, room number, and medical record number?
• Is this patient getting admitted or admitted currently?
• Is the rash the reason for admission? (This can greatly help with triaging the urgency of evaluation.)
• Is the rash painful?
• Is this patient ill?
• How would you describe the rash?

When evaluating new patients, it is crucial to remember the morphology camps. Formulating a differential diagnosis on a complex patient can be difficult; however, remembering the morphology camps of acneiform, dermal, eczematous, erythematous, subcutaneous, vasculitic, vasculopathic, and vesiculobullous lesions can be extremely helpful. Additionally, it is crucial to perform a thorough and complete skin examination on every patient. When emphasizing the importance of this, I often am reminded of a humbling moment early in my training. Our team was consulted on a patient with cellulitis and stasis dermatitis. It was a busy day, and my examination was quick and focused on the lower and upper extremities, chest, and back. The patient improved from a cutaneous standpoint and was discharged. At follow-up the next week, one of my attending providers biopsied an atypical macule on the retroauricular region, which was found to be consistent with a stage 1A melanoma. Even on the longest and most tiring hospital days, it is important to perform a full-body skin examination on each patient. You may end up saving a life.

An Organized Toolbox: What to Carry

Similar to our ophthalmology colleagues who are seen carrying around a suitcase in the hospital, I highly recommend some form of a toolbox or bag for performing inpatient biopsies (Table). Carrying around an organized bag, albeit bulky and unfashionable, has saved me numerous trips back to clinic for unexpected complications including fixing leaky vessels, closing stubborn ulcers, and coordinating sedated biopsies in the operating room.

Final Thoughts

As I near the completion of my residency journey, I hope these tips will aid budding and current dermatology residents at excelling as dermatology hospitalists during inpatient rotations. Dermatologists can make a profound impact on a variety of patients, especially when treating hospitalized patients on the clinical forefront. Our role extends beyond the skin, as cutaneous manifestations of internal disease are not uncommon.

The Diagnosis: PASH (Pyoderma Gangrenosum, Acne, Hidradenitis Suppurativa) Syndrome

Obtaining our patient’s history of hidradenitis suppurativa (HS), a hallmark sterile neutrophilic dermatosis, was key to making the correct diagnosis of PASH (pyoderma gangrenosum, acne, HS) syndrome. In our patient, the history of HS increased the consideration of pyoderma gangrenosum (PG) due to the persistent breast and leg wounds. Additionally, it was important to consider a diagnosis of PG in lesions that were not responding to broad-spectrum antimicrobial treatment. In our patient, the concurrent presentation of draining abscesses in the axillae (Figure, A) and inflammatory nodulocystic facial acne (Figure, B) were additional diagnostic clues that suggested the triad of PASH syndrome.

Although SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome also can present with cutaneous features of acne and HS, the lack of bone and joint involvement in our patient made this diagnosis less likely. Calciphylaxis can present as ulcerations on the lower extremities, but it usually presents with a livedolike pattern with overlying black eschar and is unlikely in the absence of underlying metabolic or renal disease. PAPA (pyogenic arthritis, PG, acne) syndrome is characterized by recurrent joint involvement and lacks features of HS. Lastly, our patient was immunocompetent with no risk factors for mycobacterial infection.

PASH syndrome is a rare inherited syndrome, but its constituent inflammatory conditions are ubiquitous. They share a common underlying mechanism consisting of overactivation of the innate immune systems driven by increased production of the inflammatory cytokines IL-1, IL-17, and tumor necrosis factor α, resulting in sterile neutrophilic dermatoses.¹ The diagnosis is based on the clinical presentation, as laboratory investigations are nondiagnostic. Biopsies and cultures can be performed to rule out infectious etiologies. Additionally, PASH syndrome is considered part of a larger spectrum of syndromes including PAPA and PAPASH (pyogenic arthritis, acne, PG, HS) syndromes. The absence of pyogenic arthritis distinguishes PASH syndrome from PAPA and PAPASH syndromes.² Clinically, PASH syndrome and the related sterile neutrophilic dermatoses share the characteristic of pronounced cutaneous involvement that substantially alters the patient’s quality of life. Cigarette smoking is an exacerbating factor and has a well-established association with HS.³ Therefore, smoking cessation should be encouraged in these patients to avoid exacerbation of the disease process.

Maintaining adequate immunosuppression is key to managing the underlying disease processes. Classic immunosuppressive agents such as systemic glucocorticoids and methotrexate may fail to satisfactorily control the disease.⁴ Treatment options currently are somewhat limited and are aimed at targeting the inflammatory cytokines that propagate the disease. The most consistent responses have been observed with anti–tumor necrosis factor α antagonists such as adalimumab, infliximab, and etanercept.⁵ Additionally, there is varied response to anakinra, suggesting the importance of selectively targeting IL-1β.⁶ Unfortunately, misdiagnosis for an infectious etiology is common, and antibiotics and debridement are of limited use for the underlying pathophysiology of PASH syndrome. Importantly, biopsy and debridement often are discouraged due to the risk of pathergy.⁷

Our case demonstrates the importance of maintaining a high clinical suspicion for immune-mediated lesions that are refractory to antimicrobial agents. Additionally, prior history of multiple neutrophilic dermatoses should prompt consideration for the PASH/PAPA/PAPASH disease spectrum. Early and accurate identification of neutrophilic dermatoses such as PG and HS are crucial to initiating proper cytokine-targeting treatment and achieving disease remission.

The Diagnosis: PASH (Pyoderma Gangrenosum, Acne, Hidradenitis Suppurativa) Syndrome

Obtaining our patient’s history of hidradenitis suppurativa (HS), a hallmark sterile neutrophilic dermatosis, was key to making the correct diagnosis of PASH (pyoderma gangrenosum, acne, HS) syndrome. In our patient, the history of HS increased the consideration of pyoderma gangrenosum (PG) due to the persistent breast and leg wounds. Additionally, it was important to consider a diagnosis of PG in lesions that were not responding to broad-spectrum antimicrobial treatment. In our patient, the concurrent presentation of draining abscesses in the axillae (Figure, A) and inflammatory nodulocystic facial acne (Figure, B) were additional diagnostic clues that suggested the triad of PASH syndrome.

Although SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome also can present with cutaneous features of acne and HS, the lack of bone and joint involvement in our patient made this diagnosis less likely. Calciphylaxis can present as ulcerations on the lower extremities, but it usually presents with a livedolike pattern with overlying black eschar and is unlikely in the absence of underlying metabolic or renal disease. PAPA (pyogenic arthritis, PG, acne) syndrome is characterized by recurrent joint involvement and lacks features of HS. Lastly, our patient was immunocompetent with no risk factors for mycobacterial infection.

PASH syndrome is a rare inherited syndrome, but its constituent inflammatory conditions are ubiquitous. They share a common underlying mechanism consisting of overactivation of the innate immune systems driven by increased production of the inflammatory cytokines IL-1, IL-17, and tumor necrosis factor α, resulting in sterile neutrophilic dermatoses.¹ The diagnosis is based on the clinical presentation, as laboratory investigations are nondiagnostic. Biopsies and cultures can be performed to rule out infectious etiologies. Additionally, PASH syndrome is considered part of a larger spectrum of syndromes including PAPA and PAPASH (pyogenic arthritis, acne, PG, HS) syndromes. The absence of pyogenic arthritis distinguishes PASH syndrome from PAPA and PAPASH syndromes.² Clinically, PASH syndrome and the related sterile neutrophilic dermatoses share the characteristic of pronounced cutaneous involvement that substantially alters the patient’s quality of life. Cigarette smoking is an exacerbating factor and has a well-established association with HS.³ Therefore, smoking cessation should be encouraged in these patients to avoid exacerbation of the disease process.

Maintaining adequate immunosuppression is key to managing the underlying disease processes. Classic immunosuppressive agents such as systemic glucocorticoids and methotrexate may fail to satisfactorily control the disease.⁴ Treatment options currently are somewhat limited and are aimed at targeting the inflammatory cytokines that propagate the disease. The most consistent responses have been observed with anti–tumor necrosis factor α antagonists such as adalimumab, infliximab, and etanercept.⁵ Additionally, there is varied response to anakinra, suggesting the importance of selectively targeting IL-1β.⁶ Unfortunately, misdiagnosis for an infectious etiology is common, and antibiotics and debridement are of limited use for the underlying pathophysiology of PASH syndrome. Importantly, biopsy and debridement often are discouraged due to the risk of pathergy.⁷

Our case demonstrates the importance of maintaining a high clinical suspicion for immune-mediated lesions that are refractory to antimicrobial agents. Additionally, prior history of multiple neutrophilic dermatoses should prompt consideration for the PASH/PAPA/PAPASH disease spectrum. Early and accurate identification of neutrophilic dermatoses such as PG and HS are crucial to initiating proper cytokine-targeting treatment and achieving disease remission.

The Diagnosis: PASH (Pyoderma Gangrenosum, Acne, Hidradenitis Suppurativa) Syndrome

Obtaining our patient’s history of hidradenitis suppurativa (HS), a hallmark sterile neutrophilic dermatosis, was key to making the correct diagnosis of PASH (pyoderma gangrenosum, acne, HS) syndrome. In our patient, the history of HS increased the consideration of pyoderma gangrenosum (PG) due to the persistent breast and leg wounds. Additionally, it was important to consider a diagnosis of PG in lesions that were not responding to broad-spectrum antimicrobial treatment. In our patient, the concurrent presentation of draining abscesses in the axillae (Figure, A) and inflammatory nodulocystic facial acne (Figure, B) were additional diagnostic clues that suggested the triad of PASH syndrome.

Although SAPHO (synovitis, acne, pustulosis, hyperostosis, osteitis) syndrome also can present with cutaneous features of acne and HS, the lack of bone and joint involvement in our patient made this diagnosis less likely. Calciphylaxis can present as ulcerations on the lower extremities, but it usually presents with a livedolike pattern with overlying black eschar and is unlikely in the absence of underlying metabolic or renal disease. PAPA (pyogenic arthritis, PG, acne) syndrome is characterized by recurrent joint involvement and lacks features of HS. Lastly, our patient was immunocompetent with no risk factors for mycobacterial infection.

PASH syndrome is a rare inherited syndrome, but its constituent inflammatory conditions are ubiquitous. They share a common underlying mechanism consisting of overactivation of the innate immune systems driven by increased production of the inflammatory cytokines IL-1, IL-17, and tumor necrosis factor α, resulting in sterile neutrophilic dermatoses.¹ The diagnosis is based on the clinical presentation, as laboratory investigations are nondiagnostic. Biopsies and cultures can be performed to rule out infectious etiologies. Additionally, PASH syndrome is considered part of a larger spectrum of syndromes including PAPA and PAPASH (pyogenic arthritis, acne, PG, HS) syndromes. The absence of pyogenic arthritis distinguishes PASH syndrome from PAPA and PAPASH syndromes.² Clinically, PASH syndrome and the related sterile neutrophilic dermatoses share the characteristic of pronounced cutaneous involvement that substantially alters the patient’s quality of life. Cigarette smoking is an exacerbating factor and has a well-established association with HS.³ Therefore, smoking cessation should be encouraged in these patients to avoid exacerbation of the disease process.

Maintaining adequate immunosuppression is key to managing the underlying disease processes. Classic immunosuppressive agents such as systemic glucocorticoids and methotrexate may fail to satisfactorily control the disease.⁴ Treatment options currently are somewhat limited and are aimed at targeting the inflammatory cytokines that propagate the disease. The most consistent responses have been observed with anti–tumor necrosis factor α antagonists such as adalimumab, infliximab, and etanercept.⁵ Additionally, there is varied response to anakinra, suggesting the importance of selectively targeting IL-1β.⁶ Unfortunately, misdiagnosis for an infectious etiology is common, and antibiotics and debridement are of limited use for the underlying pathophysiology of PASH syndrome. Importantly, biopsy and debridement often are discouraged due to the risk of pathergy.⁷

Our case demonstrates the importance of maintaining a high clinical suspicion for immune-mediated lesions that are refractory to antimicrobial agents. Additionally, prior history of multiple neutrophilic dermatoses should prompt consideration for the PASH/PAPA/PAPASH disease spectrum. Early and accurate identification of neutrophilic dermatoses such as PG and HS are crucial to initiating proper cytokine-targeting treatment and achieving disease remission.

To the Editor:

Pemphigoid gestationis (PG), or gestational pemphigoid, is a rare autoimmune bullous disease (AIBD) occurring in 1 in 50,000 pregnancies. It is characterized by abrupt development of intensely pruritic papules and urticarial plaques, followed by an eruption of blisters.¹ We present a case of new-onset PG that erupted 10 days following SARs-CoV-2 messenger RNA (mRNA) vaccination with BNT162b2 (Pfizer-BioNTech).

A 36-year-old pregnant woman (gravida 1, para 0, aborta 0) at 37 weeks’ gestation presented to our AIBD clinic with a pruritic dermatitis of 6 weeks’ duration that developed 10 days after receiving the second dose of BNT162b2. Multiple intensely pruritic, red bumps presented first on the forearms and within days spread to the thighs, hands, and abdomen, followed by progression to the ankles, feet, and back 2 weeks later. An initial biopsy was consistent with subacute spongiotic dermatitis with rare eosinophils. She found minimal relief from diphenhydramine or topical steroids. She denied oral, nasal, ocular, or genital involvement or history of any other skin disease. The pregnancy had been otherwise uneventful.

Physical examination revealed annular edematous plaques on the trunk and buttocks; excoriated and erythematous papules on the neck, trunk, arms, and legs; and scattered vesicles along the fingers, arms, hands, abdomen, back, legs, and feet (Figure 1). The Bullous Pemphigoid Disease Area Index (BPDAI) total skin activity score was 25.3, corresponding to moderate disease activity (validated at 20–56).² The BPDAI total pruritus component score was 20. A repeat biopsy for direct immunofluorescence showed faint linear deposits of IgG and bright linear deposits of C3 along the basement membrane zone. Indirect immunofluorescence showed linear deposits of IgG localized to the blister roof of salt-split skin at a dilution of 1:40. An enzyme-linked immunosorbent assay for anti-BP180 was 62 U/mL (negative, <9 U/mL; positive, ≥9 U/mL), and anti-BP230 autoantibodies were less than 9 U/mL (negative <9 U/mL; positive, ≥9 U/mL). Given these clinical and histopathologic findings, PG was diagnosed. 

The patient was started on prednisone 20 mg and antihistamines while continuing topical steroids. Pruritus and blistering improved close to delivery. Fetal monitoring with regular biophysical profiles remained normal. The patient delivered a healthy neonate without skin lesions at 40 weeks’ gestation. The disease flared 2 days after delivery, and prednisone was increased to 40 mg and slowly tapered. Two months after delivery, the patient remained on prednisone 10 mg daily with ongoing but reduced blistering and pruritus (Figure 2). The BPDAI total skin activity and pruritus component scores remained elevated at 20.3 and 14, respectively, and anti-BP180 was 44 U/mL. After a discussion with the patient on safe systemic therapy while breastfeeding, intravenous immunoglobulin (IVIG) was initiated. The patient received 3 monthly infusions at 2 g/kg and was able to taper the prednisone to 5 mg every other day without new lesions. Four months after completion of IVIG therapy, she achieved complete remission off all therapy.

Management of PG begins with topical corticosteroids, but most patients require systemic steroid therapy.¹ Remission commonly occurs close to delivery, and 75% of patients flare post partum, though the disease typically resolves 6 months following delivery.^1,3,4 For persistent intrapartum cases requiring more than prednisone 20 mg daily, therapy can include dapsone, IVIG, azathioprine, rituximab, or plasmapheresis.^4,5 Dapsone and IVIG are compatible with breastfeeding postpartum, but if dapsone is selected, the infant must be monitored for hemolytic anemia.⁵ Pemphigoid gestationis increases the risk for a premature or small-for-gestational-age neonate, necessitating regular fetal monitoring until delivery.¹ Cutaneous lesions may affect the newborn, though this occurrence is rare and self-limiting.⁶Pemphigoid gestationis may recur in subsequent pregnancies at a rate of 33% to 55%, with earlier and more severe presentations.⁴

Clinically and histologically, PG closely resembles bullous pemphigoid (BP), but the exact pathogenesis is not fully understood. Recently, another case of what was termed pseudo-PG has been described 3 days following administration of the second dose of the Pfizer-BioNTech COVID-19 vaccine.⁷ Since the introduction of COVID-19 mRNA vaccines, cases of postvaccination BP, BP-like eruptions, and pemphigus vulgaris have been described.^8-11 Tomayko et al¹⁰ reported 12 cases of subepidermal eruptions, including BP, in which 7 patients developed blisters after the second dose of either the Pfizer-BioNTech or Moderna mRNA vaccine. Three patients who developed BP after the first dose of the vaccine and chose to receive the second dose tolerated it well, with a mild flare observed in 1 patient.¹⁰ Similarly, subsequent vaccine doses in reports of vaccine-associated AIBD resulted in increased disease activity in 21% of cases.¹² COVID-19 vaccine–associated BP, similar to drug-induced BP, seemingly displays a milder course of disease compared to the classic form of BP.^10,13 More follow-up is needed to better understand these reactions and inform appropriate discussions on the administration of booster doses. Currently, completion of the vaccination series against COVID-19 is advisable given the paucity of reports of postvaccination AIBD and the risk for COVID-19 infection, but careful discussions on a case-by-case basis are warranted related to the risk for disease exacerbation following subsequent vaccinations.

The clinical presentation and diagnostic evaluation of our patient’s rash were consistent with PG. The temporal relationship between vaccine administration and PG lesion onset suggests the mRNA vaccine triggered AIBD in our patient. Interestingly, AIBD associated with COVID-19 is not unique to only the vaccines and has been observed following infection with the virus itself.¹⁴ The high rate of vaccination against COVID-19 in contrast with the low number of reported cases of AIBD after vaccination supports the overall safety of COVID-19 vaccines but identifies a need for further understanding of the processes that lead to the development of autoimmune conditions in at-risk populations.

To the Editor:

Pemphigoid gestationis (PG), or gestational pemphigoid, is a rare autoimmune bullous disease (AIBD) occurring in 1 in 50,000 pregnancies. It is characterized by abrupt development of intensely pruritic papules and urticarial plaques, followed by an eruption of blisters.¹ We present a case of new-onset PG that erupted 10 days following SARs-CoV-2 messenger RNA (mRNA) vaccination with BNT162b2 (Pfizer-BioNTech).

A 36-year-old pregnant woman (gravida 1, para 0, aborta 0) at 37 weeks’ gestation presented to our AIBD clinic with a pruritic dermatitis of 6 weeks’ duration that developed 10 days after receiving the second dose of BNT162b2. Multiple intensely pruritic, red bumps presented first on the forearms and within days spread to the thighs, hands, and abdomen, followed by progression to the ankles, feet, and back 2 weeks later. An initial biopsy was consistent with subacute spongiotic dermatitis with rare eosinophils. She found minimal relief from diphenhydramine or topical steroids. She denied oral, nasal, ocular, or genital involvement or history of any other skin disease. The pregnancy had been otherwise uneventful.

Physical examination revealed annular edematous plaques on the trunk and buttocks; excoriated and erythematous papules on the neck, trunk, arms, and legs; and scattered vesicles along the fingers, arms, hands, abdomen, back, legs, and feet (Figure 1). The Bullous Pemphigoid Disease Area Index (BPDAI) total skin activity score was 25.3, corresponding to moderate disease activity (validated at 20–56).² The BPDAI total pruritus component score was 20. A repeat biopsy for direct immunofluorescence showed faint linear deposits of IgG and bright linear deposits of C3 along the basement membrane zone. Indirect immunofluorescence showed linear deposits of IgG localized to the blister roof of salt-split skin at a dilution of 1:40. An enzyme-linked immunosorbent assay for anti-BP180 was 62 U/mL (negative, <9 U/mL; positive, ≥9 U/mL), and anti-BP230 autoantibodies were less than 9 U/mL (negative <9 U/mL; positive, ≥9 U/mL). Given these clinical and histopathologic findings, PG was diagnosed. 

The patient was started on prednisone 20 mg and antihistamines while continuing topical steroids. Pruritus and blistering improved close to delivery. Fetal monitoring with regular biophysical profiles remained normal. The patient delivered a healthy neonate without skin lesions at 40 weeks’ gestation. The disease flared 2 days after delivery, and prednisone was increased to 40 mg and slowly tapered. Two months after delivery, the patient remained on prednisone 10 mg daily with ongoing but reduced blistering and pruritus (Figure 2). The BPDAI total skin activity and pruritus component scores remained elevated at 20.3 and 14, respectively, and anti-BP180 was 44 U/mL. After a discussion with the patient on safe systemic therapy while breastfeeding, intravenous immunoglobulin (IVIG) was initiated. The patient received 3 monthly infusions at 2 g/kg and was able to taper the prednisone to 5 mg every other day without new lesions. Four months after completion of IVIG therapy, she achieved complete remission off all therapy.

Management of PG begins with topical corticosteroids, but most patients require systemic steroid therapy.¹ Remission commonly occurs close to delivery, and 75% of patients flare post partum, though the disease typically resolves 6 months following delivery.^1,3,4 For persistent intrapartum cases requiring more than prednisone 20 mg daily, therapy can include dapsone, IVIG, azathioprine, rituximab, or plasmapheresis.^4,5 Dapsone and IVIG are compatible with breastfeeding postpartum, but if dapsone is selected, the infant must be monitored for hemolytic anemia.⁵ Pemphigoid gestationis increases the risk for a premature or small-for-gestational-age neonate, necessitating regular fetal monitoring until delivery.¹ Cutaneous lesions may affect the newborn, though this occurrence is rare and self-limiting.⁶Pemphigoid gestationis may recur in subsequent pregnancies at a rate of 33% to 55%, with earlier and more severe presentations.⁴

Clinically and histologically, PG closely resembles bullous pemphigoid (BP), but the exact pathogenesis is not fully understood. Recently, another case of what was termed pseudo-PG has been described 3 days following administration of the second dose of the Pfizer-BioNTech COVID-19 vaccine.⁷ Since the introduction of COVID-19 mRNA vaccines, cases of postvaccination BP, BP-like eruptions, and pemphigus vulgaris have been described.^8-11 Tomayko et al¹⁰ reported 12 cases of subepidermal eruptions, including BP, in which 7 patients developed blisters after the second dose of either the Pfizer-BioNTech or Moderna mRNA vaccine. Three patients who developed BP after the first dose of the vaccine and chose to receive the second dose tolerated it well, with a mild flare observed in 1 patient.¹⁰ Similarly, subsequent vaccine doses in reports of vaccine-associated AIBD resulted in increased disease activity in 21% of cases.¹² COVID-19 vaccine–associated BP, similar to drug-induced BP, seemingly displays a milder course of disease compared to the classic form of BP.^10,13 More follow-up is needed to better understand these reactions and inform appropriate discussions on the administration of booster doses. Currently, completion of the vaccination series against COVID-19 is advisable given the paucity of reports of postvaccination AIBD and the risk for COVID-19 infection, but careful discussions on a case-by-case basis are warranted related to the risk for disease exacerbation following subsequent vaccinations.

The clinical presentation and diagnostic evaluation of our patient’s rash were consistent with PG. The temporal relationship between vaccine administration and PG lesion onset suggests the mRNA vaccine triggered AIBD in our patient. Interestingly, AIBD associated with COVID-19 is not unique to only the vaccines and has been observed following infection with the virus itself.¹⁴ The high rate of vaccination against COVID-19 in contrast with the low number of reported cases of AIBD after vaccination supports the overall safety of COVID-19 vaccines but identifies a need for further understanding of the processes that lead to the development of autoimmune conditions in at-risk populations.

To the Editor:

Pemphigoid gestationis (PG), or gestational pemphigoid, is a rare autoimmune bullous disease (AIBD) occurring in 1 in 50,000 pregnancies. It is characterized by abrupt development of intensely pruritic papules and urticarial plaques, followed by an eruption of blisters.¹ We present a case of new-onset PG that erupted 10 days following SARs-CoV-2 messenger RNA (mRNA) vaccination with BNT162b2 (Pfizer-BioNTech).

A 36-year-old pregnant woman (gravida 1, para 0, aborta 0) at 37 weeks’ gestation presented to our AIBD clinic with a pruritic dermatitis of 6 weeks’ duration that developed 10 days after receiving the second dose of BNT162b2. Multiple intensely pruritic, red bumps presented first on the forearms and within days spread to the thighs, hands, and abdomen, followed by progression to the ankles, feet, and back 2 weeks later. An initial biopsy was consistent with subacute spongiotic dermatitis with rare eosinophils. She found minimal relief from diphenhydramine or topical steroids. She denied oral, nasal, ocular, or genital involvement or history of any other skin disease. The pregnancy had been otherwise uneventful.

Physical examination revealed annular edematous plaques on the trunk and buttocks; excoriated and erythematous papules on the neck, trunk, arms, and legs; and scattered vesicles along the fingers, arms, hands, abdomen, back, legs, and feet (Figure 1). The Bullous Pemphigoid Disease Area Index (BPDAI) total skin activity score was 25.3, corresponding to moderate disease activity (validated at 20–56).² The BPDAI total pruritus component score was 20. A repeat biopsy for direct immunofluorescence showed faint linear deposits of IgG and bright linear deposits of C3 along the basement membrane zone. Indirect immunofluorescence showed linear deposits of IgG localized to the blister roof of salt-split skin at a dilution of 1:40. An enzyme-linked immunosorbent assay for anti-BP180 was 62 U/mL (negative, <9 U/mL; positive, ≥9 U/mL), and anti-BP230 autoantibodies were less than 9 U/mL (negative <9 U/mL; positive, ≥9 U/mL). Given these clinical and histopathologic findings, PG was diagnosed. 

The patient was started on prednisone 20 mg and antihistamines while continuing topical steroids. Pruritus and blistering improved close to delivery. Fetal monitoring with regular biophysical profiles remained normal. The patient delivered a healthy neonate without skin lesions at 40 weeks’ gestation. The disease flared 2 days after delivery, and prednisone was increased to 40 mg and slowly tapered. Two months after delivery, the patient remained on prednisone 10 mg daily with ongoing but reduced blistering and pruritus (Figure 2). The BPDAI total skin activity and pruritus component scores remained elevated at 20.3 and 14, respectively, and anti-BP180 was 44 U/mL. After a discussion with the patient on safe systemic therapy while breastfeeding, intravenous immunoglobulin (IVIG) was initiated. The patient received 3 monthly infusions at 2 g/kg and was able to taper the prednisone to 5 mg every other day without new lesions. Four months after completion of IVIG therapy, she achieved complete remission off all therapy.

Management of PG begins with topical corticosteroids, but most patients require systemic steroid therapy.¹ Remission commonly occurs close to delivery, and 75% of patients flare post partum, though the disease typically resolves 6 months following delivery.^1,3,4 For persistent intrapartum cases requiring more than prednisone 20 mg daily, therapy can include dapsone, IVIG, azathioprine, rituximab, or plasmapheresis.^4,5 Dapsone and IVIG are compatible with breastfeeding postpartum, but if dapsone is selected, the infant must be monitored for hemolytic anemia.⁵ Pemphigoid gestationis increases the risk for a premature or small-for-gestational-age neonate, necessitating regular fetal monitoring until delivery.¹ Cutaneous lesions may affect the newborn, though this occurrence is rare and self-limiting.⁶Pemphigoid gestationis may recur in subsequent pregnancies at a rate of 33% to 55%, with earlier and more severe presentations.⁴

Clinically and histologically, PG closely resembles bullous pemphigoid (BP), but the exact pathogenesis is not fully understood. Recently, another case of what was termed pseudo-PG has been described 3 days following administration of the second dose of the Pfizer-BioNTech COVID-19 vaccine.⁷ Since the introduction of COVID-19 mRNA vaccines, cases of postvaccination BP, BP-like eruptions, and pemphigus vulgaris have been described.^8-11 Tomayko et al¹⁰ reported 12 cases of subepidermal eruptions, including BP, in which 7 patients developed blisters after the second dose of either the Pfizer-BioNTech or Moderna mRNA vaccine. Three patients who developed BP after the first dose of the vaccine and chose to receive the second dose tolerated it well, with a mild flare observed in 1 patient.¹⁰ Similarly, subsequent vaccine doses in reports of vaccine-associated AIBD resulted in increased disease activity in 21% of cases.¹² COVID-19 vaccine–associated BP, similar to drug-induced BP, seemingly displays a milder course of disease compared to the classic form of BP.^10,13 More follow-up is needed to better understand these reactions and inform appropriate discussions on the administration of booster doses. Currently, completion of the vaccination series against COVID-19 is advisable given the paucity of reports of postvaccination AIBD and the risk for COVID-19 infection, but careful discussions on a case-by-case basis are warranted related to the risk for disease exacerbation following subsequent vaccinations.

The clinical presentation and diagnostic evaluation of our patient’s rash were consistent with PG. The temporal relationship between vaccine administration and PG lesion onset suggests the mRNA vaccine triggered AIBD in our patient. Interestingly, AIBD associated with COVID-19 is not unique to only the vaccines and has been observed following infection with the virus itself.¹⁴ The high rate of vaccination against COVID-19 in contrast with the low number of reported cases of AIBD after vaccination supports the overall safety of COVID-19 vaccines but identifies a need for further understanding of the processes that lead to the development of autoimmune conditions in at-risk populations.

The Diagnosis: Prurigo Pigmentosa 

Histopathology of the punch biopsy revealed subcorneal collections of neutrophils flanked by a spongiotic epidermis with neutrophil and eosinophil exocytosis. Rare dyskeratotic keratinocytes were identified at the dermoepidermal junction, and grampositive bacterial organisms were seen in a follicular infundibulum with purulent inflammation. The dermis demonstrated a mildly dense superficial perivascular and interstitial infiltrate composed of lymphocytes, histiocytes, scattered neutrophils, and eosinophils (Figure).

Given the combination of clinical and histologic findings, a diagnosis of prurigo pigmentosa (PP) was rendered and a urinalysis was ordered, which confirmed ketonuria. The patient was started on minocycline 100 mg twice daily and was advised to reintroduce carbohydrates into her diet. Resolution of the inflammatory component of the rash was achieved at 3-week follow-up, with residual reticulated postinflammatory hyperpigmentation.

Prurigo pigmentosa is a rare, albeit globally underrecognized, inflammatory dermatosis characterized by pruritic, symmetric, erythematous papules and plaques on the chest, back, neck, and rarely the arms and forehead that subsequently involute, leaving reticular postinflammatory hyperpigmentation.1 Prurigo pigmentosa is predominant in females (2.6:1 ratio). The mean age at presentation is 24.4 years, and it most commonly has been documented among populations in Asian countries, though it is unclear if a genetic predilection exists, as reports of PP are increasing globally with improved clinical awareness.^1,2

The etiology of PP remains unknown; however, associations are well documented between PP and a ketogenic state secondary to uncontrolled diabetes, a low-carbohydrate diet, anorexia nervosa, or bariatric surgery.³ It is theorized that high serum ketones lead to perivascular ketone deposition, which induces neutrophil migration and chemotaxis,⁴ as substantiated by evidence of rash resolution with correction of the ketogenic state and improvement after administration of tetracyclines, a drug class known for neutrophil chemotaxis inhibition.⁵ Improvement of PP via these treatment mechanisms suggests that ketone bodies may play a role in the pathogenesis of PP.

Interestingly, Kafle et al⁶ reported that patients with PP commonly have bacterial colonies and associated inflammatory sequelae at the level of the hair follicles, which suggests that follicular involvement plays a role in the pathogenesis of PP. These findings are consistent with our patient’s histopathology consisting of gram-positive organisms and purulent inflammation at the infundibulum. The histopathologic features of PP are stage specific.¹ Early stages are characterized by a superficial perivascular infiltrate of neutrophils that then spread to dermal papillae. Neutrophils then quickly sweep through the epidermis, causing spongiosis, ballooning, necrotic keratocytes, and consequent surface epithelium abscess formation. Over time, the dermal infiltrate assumes a lichenoid pattern as eosinophils and lymphocytes invade and predominate over neutrophils. Eventually, melanophages appear in the dermis as the epidermis undergoes hyperplasia, parakeratosis, and hyperpigmentation.¹ The histologic differential diagnosis for PP is broad and varies based on the stage-specific progression of clinical and histopathologic findings.

Similar to PP, subacute cutaneous lupus erythematosus has a female predominance and resolves with subsequent dyspigmentation; however, it initially is characterized by annular plaques with central clearing or papulosquamous lesions restricted to sun-exposed skin. Photosensitivity is a prominent feature, and roughly 50% of patients meet diagnostic criteria for systemic lupus erythematosus.⁷ Histopathology shows interface changes with increased dermal mucin and a perivascular lymphoplasmacytic inflammatory infiltrate.

Papular pityriasis rosea can present as a pruritic papular rash on the back and chest; however, it most commonly is associated with a herald patch and typically follows a flulike prodrome.⁸ Biopsy reveals mounds of parakeratosis with mild spongiosis, perivascular inflammation, and extravasated erythrocytes.

Galli-Galli disease can present as a pruritic rash with follicular papules under the breasts and other flexural areas but histopathologically shows elongated rete ridges with dermal melanosis and acantholysis.⁹

Hailey-Hailey disease commonly presents in the third decade of life and can manifest as painful, pruritic, vesicular lesions on erythematous skin distributed on the back, neck, and inframammary region, as seen in our case; however, it is histopathologically associated with widespread epidermal acantholysis unlike the findings seen in our patient.¹⁰

First-line treatment of PP includes antibiotics such as minocycline, doxycycline, and dapsone due to their anti-inflammatory properties and ability to inhibit neutrophil chemotaxis. In patients with nutritional deficiencies or ketosis, reintroduction of carbohydrates alone has been effective.^5,11

Prurigo pigmentosa is an underrecognized inflammatory dermatosis with a complex stage-dependent clinicopathologic presentation. Clinicians should be aware of the etiologic and histopathologic patterns of this unique dermatosis. Rash presentation in the context of a low-carbohydrate diet should prompt biopsy as well as treatment with antibiotics and dietary reintroduction of carbohydrates.

The Diagnosis: Prurigo Pigmentosa 

Histopathology of the punch biopsy revealed subcorneal collections of neutrophils flanked by a spongiotic epidermis with neutrophil and eosinophil exocytosis. Rare dyskeratotic keratinocytes were identified at the dermoepidermal junction, and grampositive bacterial organisms were seen in a follicular infundibulum with purulent inflammation. The dermis demonstrated a mildly dense superficial perivascular and interstitial infiltrate composed of lymphocytes, histiocytes, scattered neutrophils, and eosinophils (Figure).

Given the combination of clinical and histologic findings, a diagnosis of prurigo pigmentosa (PP) was rendered and a urinalysis was ordered, which confirmed ketonuria. The patient was started on minocycline 100 mg twice daily and was advised to reintroduce carbohydrates into her diet. Resolution of the inflammatory component of the rash was achieved at 3-week follow-up, with residual reticulated postinflammatory hyperpigmentation.

Prurigo pigmentosa is a rare, albeit globally underrecognized, inflammatory dermatosis characterized by pruritic, symmetric, erythematous papules and plaques on the chest, back, neck, and rarely the arms and forehead that subsequently involute, leaving reticular postinflammatory hyperpigmentation.1 Prurigo pigmentosa is predominant in females (2.6:1 ratio). The mean age at presentation is 24.4 years, and it most commonly has been documented among populations in Asian countries, though it is unclear if a genetic predilection exists, as reports of PP are increasing globally with improved clinical awareness.^1,2

The etiology of PP remains unknown; however, associations are well documented between PP and a ketogenic state secondary to uncontrolled diabetes, a low-carbohydrate diet, anorexia nervosa, or bariatric surgery.³ It is theorized that high serum ketones lead to perivascular ketone deposition, which induces neutrophil migration and chemotaxis,⁴ as substantiated by evidence of rash resolution with correction of the ketogenic state and improvement after administration of tetracyclines, a drug class known for neutrophil chemotaxis inhibition.⁵ Improvement of PP via these treatment mechanisms suggests that ketone bodies may play a role in the pathogenesis of PP.

Interestingly, Kafle et al⁶ reported that patients with PP commonly have bacterial colonies and associated inflammatory sequelae at the level of the hair follicles, which suggests that follicular involvement plays a role in the pathogenesis of PP. These findings are consistent with our patient’s histopathology consisting of gram-positive organisms and purulent inflammation at the infundibulum. The histopathologic features of PP are stage specific.¹ Early stages are characterized by a superficial perivascular infiltrate of neutrophils that then spread to dermal papillae. Neutrophils then quickly sweep through the epidermis, causing spongiosis, ballooning, necrotic keratocytes, and consequent surface epithelium abscess formation. Over time, the dermal infiltrate assumes a lichenoid pattern as eosinophils and lymphocytes invade and predominate over neutrophils. Eventually, melanophages appear in the dermis as the epidermis undergoes hyperplasia, parakeratosis, and hyperpigmentation.¹ The histologic differential diagnosis for PP is broad and varies based on the stage-specific progression of clinical and histopathologic findings.

Similar to PP, subacute cutaneous lupus erythematosus has a female predominance and resolves with subsequent dyspigmentation; however, it initially is characterized by annular plaques with central clearing or papulosquamous lesions restricted to sun-exposed skin. Photosensitivity is a prominent feature, and roughly 50% of patients meet diagnostic criteria for systemic lupus erythematosus.⁷ Histopathology shows interface changes with increased dermal mucin and a perivascular lymphoplasmacytic inflammatory infiltrate.

Papular pityriasis rosea can present as a pruritic papular rash on the back and chest; however, it most commonly is associated with a herald patch and typically follows a flulike prodrome.⁸ Biopsy reveals mounds of parakeratosis with mild spongiosis, perivascular inflammation, and extravasated erythrocytes.

Galli-Galli disease can present as a pruritic rash with follicular papules under the breasts and other flexural areas but histopathologically shows elongated rete ridges with dermal melanosis and acantholysis.⁹

Hailey-Hailey disease commonly presents in the third decade of life and can manifest as painful, pruritic, vesicular lesions on erythematous skin distributed on the back, neck, and inframammary region, as seen in our case; however, it is histopathologically associated with widespread epidermal acantholysis unlike the findings seen in our patient.¹⁰

First-line treatment of PP includes antibiotics such as minocycline, doxycycline, and dapsone due to their anti-inflammatory properties and ability to inhibit neutrophil chemotaxis. In patients with nutritional deficiencies or ketosis, reintroduction of carbohydrates alone has been effective.^5,11

Prurigo pigmentosa is an underrecognized inflammatory dermatosis with a complex stage-dependent clinicopathologic presentation. Clinicians should be aware of the etiologic and histopathologic patterns of this unique dermatosis. Rash presentation in the context of a low-carbohydrate diet should prompt biopsy as well as treatment with antibiotics and dietary reintroduction of carbohydrates.

The Diagnosis: Prurigo Pigmentosa 

Histopathology of the punch biopsy revealed subcorneal collections of neutrophils flanked by a spongiotic epidermis with neutrophil and eosinophil exocytosis. Rare dyskeratotic keratinocytes were identified at the dermoepidermal junction, and grampositive bacterial organisms were seen in a follicular infundibulum with purulent inflammation. The dermis demonstrated a mildly dense superficial perivascular and interstitial infiltrate composed of lymphocytes, histiocytes, scattered neutrophils, and eosinophils (Figure).

Given the combination of clinical and histologic findings, a diagnosis of prurigo pigmentosa (PP) was rendered and a urinalysis was ordered, which confirmed ketonuria. The patient was started on minocycline 100 mg twice daily and was advised to reintroduce carbohydrates into her diet. Resolution of the inflammatory component of the rash was achieved at 3-week follow-up, with residual reticulated postinflammatory hyperpigmentation.

Prurigo pigmentosa is a rare, albeit globally underrecognized, inflammatory dermatosis characterized by pruritic, symmetric, erythematous papules and plaques on the chest, back, neck, and rarely the arms and forehead that subsequently involute, leaving reticular postinflammatory hyperpigmentation.1 Prurigo pigmentosa is predominant in females (2.6:1 ratio). The mean age at presentation is 24.4 years, and it most commonly has been documented among populations in Asian countries, though it is unclear if a genetic predilection exists, as reports of PP are increasing globally with improved clinical awareness.^1,2

The etiology of PP remains unknown; however, associations are well documented between PP and a ketogenic state secondary to uncontrolled diabetes, a low-carbohydrate diet, anorexia nervosa, or bariatric surgery.³ It is theorized that high serum ketones lead to perivascular ketone deposition, which induces neutrophil migration and chemotaxis,⁴ as substantiated by evidence of rash resolution with correction of the ketogenic state and improvement after administration of tetracyclines, a drug class known for neutrophil chemotaxis inhibition.⁵ Improvement of PP via these treatment mechanisms suggests that ketone bodies may play a role in the pathogenesis of PP.

Interestingly, Kafle et al⁶ reported that patients with PP commonly have bacterial colonies and associated inflammatory sequelae at the level of the hair follicles, which suggests that follicular involvement plays a role in the pathogenesis of PP. These findings are consistent with our patient’s histopathology consisting of gram-positive organisms and purulent inflammation at the infundibulum. The histopathologic features of PP are stage specific.¹ Early stages are characterized by a superficial perivascular infiltrate of neutrophils that then spread to dermal papillae. Neutrophils then quickly sweep through the epidermis, causing spongiosis, ballooning, necrotic keratocytes, and consequent surface epithelium abscess formation. Over time, the dermal infiltrate assumes a lichenoid pattern as eosinophils and lymphocytes invade and predominate over neutrophils. Eventually, melanophages appear in the dermis as the epidermis undergoes hyperplasia, parakeratosis, and hyperpigmentation.¹ The histologic differential diagnosis for PP is broad and varies based on the stage-specific progression of clinical and histopathologic findings.

Similar to PP, subacute cutaneous lupus erythematosus has a female predominance and resolves with subsequent dyspigmentation; however, it initially is characterized by annular plaques with central clearing or papulosquamous lesions restricted to sun-exposed skin. Photosensitivity is a prominent feature, and roughly 50% of patients meet diagnostic criteria for systemic lupus erythematosus.⁷ Histopathology shows interface changes with increased dermal mucin and a perivascular lymphoplasmacytic inflammatory infiltrate.

Papular pityriasis rosea can present as a pruritic papular rash on the back and chest; however, it most commonly is associated with a herald patch and typically follows a flulike prodrome.⁸ Biopsy reveals mounds of parakeratosis with mild spongiosis, perivascular inflammation, and extravasated erythrocytes.

Galli-Galli disease can present as a pruritic rash with follicular papules under the breasts and other flexural areas but histopathologically shows elongated rete ridges with dermal melanosis and acantholysis.⁹

Hailey-Hailey disease commonly presents in the third decade of life and can manifest as painful, pruritic, vesicular lesions on erythematous skin distributed on the back, neck, and inframammary region, as seen in our case; however, it is histopathologically associated with widespread epidermal acantholysis unlike the findings seen in our patient.¹⁰

First-line treatment of PP includes antibiotics such as minocycline, doxycycline, and dapsone due to their anti-inflammatory properties and ability to inhibit neutrophil chemotaxis. In patients with nutritional deficiencies or ketosis, reintroduction of carbohydrates alone has been effective.^5,11

Prurigo pigmentosa is an underrecognized inflammatory dermatosis with a complex stage-dependent clinicopathologic presentation. Clinicians should be aware of the etiologic and histopathologic patterns of this unique dermatosis. Rash presentation in the context of a low-carbohydrate diet should prompt biopsy as well as treatment with antibiotics and dietary reintroduction of carbohydrates.

To the Editor:

Miliarial gout is a rare intradermal manifestation of tophaceous gout. It was first described in 2007 when a patient presented with multiple small papules with a red base containing a white- to cream-colored substance,¹ which has rarely been reported,^1-6 according to a PubMed search of articles indexed for MEDLINE from 2007 to 2023 using the term miliarial gout. We describe a case of miliarial gout in a patient with a history of gout, uric acid levels within reference range, and immunocompromised status due to a prior orthotopic heart transplant.

A 59-year-old man presented with innumerable subcutaneous, firm, popcornlike clustered papules on the posterior surfaces of the upper arms and thighs of 5 years’ duration (Figure 1). The involved areas were sometimes painful on manipulation, but the patient was otherwise asymptomatic. His medical history was notable for tophaceous gout of more than 10 years’ duration, calcinosis cutis, adrenal insufficiency, essential hypertension, and an orthotopic heart transplant 2 years prior to the current presentation. At the current presentation he was taking tacrolimus, colchicine, febuxostat, and low-dose prednisone. The patient denied any other skin changes such as ulceration or bullae. In addition to the innumerable subcutaneous papules, he had much larger firm deep nodules bilaterally on the elbow (Figure 2). A complete blood cell count with differential and comprehensive metabolic panel results were within reference range. A 4-mm punch biopsy of the right posterior arm revealed dermal deposits consistent with gout on hematoxylin and eosin staining (Figure 3) but no calcium deposits on von Kossa staining, consistent with miliarial gout.

He was treated with 0.6 mg of colchicine daily, 80 mg of febuxostat twice daily, and 2.5 mg of prednisone daily. Unfortunately, the patient had difficulty affording his medications and therefore experienced frequent flares.

Gout is caused by inflammation that occurs from deposition of monosodium urate crystals in tissues, most commonly occurring in the skin and joints. Gout affects8.3 million individuals and is one of the most common rheumatic diseases of adulthood. The classic presentation of the acute form is monoarticular with associated swelling, erythema, and pain. The chronic form (also known as tophaceous gout) affects soft tissue and presents with smooth or multilobulated nodules.² Miliarial gout is a rare variant of chronic tophaceous gout, and the diagnosis is based on atypical location, size, and distribution of tophi deposition.

In the updated American College of Rheumatology criteria for gout published in 2020, tophi are defined as draining or chalklike subcutaneous nodules that typically are located in joints, ears, olecranon bursae, finger pads, and tendons.³ The term miliarial gout, which is not universally defined, is used to describe the morphology and distribution of tophi deposition in areas outside of the typical locations defined by the American College of Rheumatology criteria. Miliarial refers to the small, multilobulated, and disseminated presentation of tophi. The involvement of atypical locations distinguishes miliarial gout from chronic tophaceous gout.

The cause of tophi deposition in atypical locations is unknown. It is thought that patients with a history of sustained hyperuricemia have a much greater burden of urate crystal deposition, which can lead to involvement of atypical locations. Our patient had innumerable, discrete, 1- to 5-mm, multilobulated tophi located on the posterior upper arms and thighs even though his uric acid levels were within reference range over the last 5 years.

Miliarial gout is a rare entity.¹ In 2007, Shukla et al¹ coined the term miliarial gout when reporting the first known presentation of a patient with multiple tiny papules containing a white or creamlike substance scattered on an erythematous base. Other cases of miliarial gout have commonly involved the metacarpophalangeal joints of the hands, knees, abdomen, extensor forearms, and thighs.⁵ Similarly, our patient had disease involvement of the posterior upper arms and thighs. Furthermore, miliarial gout has been associated with carpal tunnel syndrome; monosodium urate crystal deposition in this space can lead to a clinical diagnosis of this condition.⁶

With a history of orthotopic heart transplant, it is possible that our patient’s immunocompromised status could have increased his susceptibility for the miliarial form of chronic tophaceous gout. Gout reportedly is the most common inflammatory arthritis in transplant recipients, with the highest prevalence following renal and heart transplantation.⁷ Pretransplant hyperuricemia is correlated with higher probabilities of posttransplant gout.⁸ In patients with a heart transplant, hyperuricemia may be due to diuretic use. Additionally, the presence of a gout diagnosis before transplant nearly triples the likelihood of posttransplant gout, which often is more severe than de novo gout, as seen in our patient. Calcineurin inhibitors, including tacrolimus, also can predispose patients to hyperuricemia and more severe forms of gout in the posttransplant phase by limiting fractional urate excretion within the first 3 months of therapy.⁷ Treatment with oral steroids, as in our patient, also has been identified as a potential inciting factor for the development of cutaneous tophaceous gout.⁹

Treatment with allopurinol and colchicine has been effective in patients with miliarial gout. Obesity and long-term treatment with furosemide (which our patient was not taking) are considered risk factors for the deposition of dermal and hypodermal urates.⁹ Our patient had a body mass index of 35 (≥30 indicates obesity); therefore, he also should be counseled on lifestyle modifications for optimal disease control.

To the Editor:

Miliarial gout is a rare intradermal manifestation of tophaceous gout. It was first described in 2007 when a patient presented with multiple small papules with a red base containing a white- to cream-colored substance,¹ which has rarely been reported,^1-6 according to a PubMed search of articles indexed for MEDLINE from 2007 to 2023 using the term miliarial gout. We describe a case of miliarial gout in a patient with a history of gout, uric acid levels within reference range, and immunocompromised status due to a prior orthotopic heart transplant.

A 59-year-old man presented with innumerable subcutaneous, firm, popcornlike clustered papules on the posterior surfaces of the upper arms and thighs of 5 years’ duration (Figure 1). The involved areas were sometimes painful on manipulation, but the patient was otherwise asymptomatic. His medical history was notable for tophaceous gout of more than 10 years’ duration, calcinosis cutis, adrenal insufficiency, essential hypertension, and an orthotopic heart transplant 2 years prior to the current presentation. At the current presentation he was taking tacrolimus, colchicine, febuxostat, and low-dose prednisone. The patient denied any other skin changes such as ulceration or bullae. In addition to the innumerable subcutaneous papules, he had much larger firm deep nodules bilaterally on the elbow (Figure 2). A complete blood cell count with differential and comprehensive metabolic panel results were within reference range. A 4-mm punch biopsy of the right posterior arm revealed dermal deposits consistent with gout on hematoxylin and eosin staining (Figure 3) but no calcium deposits on von Kossa staining, consistent with miliarial gout.

He was treated with 0.6 mg of colchicine daily, 80 mg of febuxostat twice daily, and 2.5 mg of prednisone daily. Unfortunately, the patient had difficulty affording his medications and therefore experienced frequent flares.

Gout is caused by inflammation that occurs from deposition of monosodium urate crystals in tissues, most commonly occurring in the skin and joints. Gout affects8.3 million individuals and is one of the most common rheumatic diseases of adulthood. The classic presentation of the acute form is monoarticular with associated swelling, erythema, and pain. The chronic form (also known as tophaceous gout) affects soft tissue and presents with smooth or multilobulated nodules.² Miliarial gout is a rare variant of chronic tophaceous gout, and the diagnosis is based on atypical location, size, and distribution of tophi deposition.

In the updated American College of Rheumatology criteria for gout published in 2020, tophi are defined as draining or chalklike subcutaneous nodules that typically are located in joints, ears, olecranon bursae, finger pads, and tendons.³ The term miliarial gout, which is not universally defined, is used to describe the morphology and distribution of tophi deposition in areas outside of the typical locations defined by the American College of Rheumatology criteria. Miliarial refers to the small, multilobulated, and disseminated presentation of tophi. The involvement of atypical locations distinguishes miliarial gout from chronic tophaceous gout.

The cause of tophi deposition in atypical locations is unknown. It is thought that patients with a history of sustained hyperuricemia have a much greater burden of urate crystal deposition, which can lead to involvement of atypical locations. Our patient had innumerable, discrete, 1- to 5-mm, multilobulated tophi located on the posterior upper arms and thighs even though his uric acid levels were within reference range over the last 5 years.

Miliarial gout is a rare entity.¹ In 2007, Shukla et al¹ coined the term miliarial gout when reporting the first known presentation of a patient with multiple tiny papules containing a white or creamlike substance scattered on an erythematous base. Other cases of miliarial gout have commonly involved the metacarpophalangeal joints of the hands, knees, abdomen, extensor forearms, and thighs.⁵ Similarly, our patient had disease involvement of the posterior upper arms and thighs. Furthermore, miliarial gout has been associated with carpal tunnel syndrome; monosodium urate crystal deposition in this space can lead to a clinical diagnosis of this condition.⁶

With a history of orthotopic heart transplant, it is possible that our patient’s immunocompromised status could have increased his susceptibility for the miliarial form of chronic tophaceous gout. Gout reportedly is the most common inflammatory arthritis in transplant recipients, with the highest prevalence following renal and heart transplantation.⁷ Pretransplant hyperuricemia is correlated with higher probabilities of posttransplant gout.⁸ In patients with a heart transplant, hyperuricemia may be due to diuretic use. Additionally, the presence of a gout diagnosis before transplant nearly triples the likelihood of posttransplant gout, which often is more severe than de novo gout, as seen in our patient. Calcineurin inhibitors, including tacrolimus, also can predispose patients to hyperuricemia and more severe forms of gout in the posttransplant phase by limiting fractional urate excretion within the first 3 months of therapy.⁷ Treatment with oral steroids, as in our patient, also has been identified as a potential inciting factor for the development of cutaneous tophaceous gout.⁹

Treatment with allopurinol and colchicine has been effective in patients with miliarial gout. Obesity and long-term treatment with furosemide (which our patient was not taking) are considered risk factors for the deposition of dermal and hypodermal urates.⁹ Our patient had a body mass index of 35 (≥30 indicates obesity); therefore, he also should be counseled on lifestyle modifications for optimal disease control.

To the Editor:

Miliarial gout is a rare intradermal manifestation of tophaceous gout. It was first described in 2007 when a patient presented with multiple small papules with a red base containing a white- to cream-colored substance,¹ which has rarely been reported,^1-6 according to a PubMed search of articles indexed for MEDLINE from 2007 to 2023 using the term miliarial gout. We describe a case of miliarial gout in a patient with a history of gout, uric acid levels within reference range, and immunocompromised status due to a prior orthotopic heart transplant.

A 59-year-old man presented with innumerable subcutaneous, firm, popcornlike clustered papules on the posterior surfaces of the upper arms and thighs of 5 years’ duration (Figure 1). The involved areas were sometimes painful on manipulation, but the patient was otherwise asymptomatic. His medical history was notable for tophaceous gout of more than 10 years’ duration, calcinosis cutis, adrenal insufficiency, essential hypertension, and an orthotopic heart transplant 2 years prior to the current presentation. At the current presentation he was taking tacrolimus, colchicine, febuxostat, and low-dose prednisone. The patient denied any other skin changes such as ulceration or bullae. In addition to the innumerable subcutaneous papules, he had much larger firm deep nodules bilaterally on the elbow (Figure 2). A complete blood cell count with differential and comprehensive metabolic panel results were within reference range. A 4-mm punch biopsy of the right posterior arm revealed dermal deposits consistent with gout on hematoxylin and eosin staining (Figure 3) but no calcium deposits on von Kossa staining, consistent with miliarial gout.

He was treated with 0.6 mg of colchicine daily, 80 mg of febuxostat twice daily, and 2.5 mg of prednisone daily. Unfortunately, the patient had difficulty affording his medications and therefore experienced frequent flares.

Gout is caused by inflammation that occurs from deposition of monosodium urate crystals in tissues, most commonly occurring in the skin and joints. Gout affects8.3 million individuals and is one of the most common rheumatic diseases of adulthood. The classic presentation of the acute form is monoarticular with associated swelling, erythema, and pain. The chronic form (also known as tophaceous gout) affects soft tissue and presents with smooth or multilobulated nodules.² Miliarial gout is a rare variant of chronic tophaceous gout, and the diagnosis is based on atypical location, size, and distribution of tophi deposition.

In the updated American College of Rheumatology criteria for gout published in 2020, tophi are defined as draining or chalklike subcutaneous nodules that typically are located in joints, ears, olecranon bursae, finger pads, and tendons.³ The term miliarial gout, which is not universally defined, is used to describe the morphology and distribution of tophi deposition in areas outside of the typical locations defined by the American College of Rheumatology criteria. Miliarial refers to the small, multilobulated, and disseminated presentation of tophi. The involvement of atypical locations distinguishes miliarial gout from chronic tophaceous gout.

The cause of tophi deposition in atypical locations is unknown. It is thought that patients with a history of sustained hyperuricemia have a much greater burden of urate crystal deposition, which can lead to involvement of atypical locations. Our patient had innumerable, discrete, 1- to 5-mm, multilobulated tophi located on the posterior upper arms and thighs even though his uric acid levels were within reference range over the last 5 years.

Miliarial gout is a rare entity.¹ In 2007, Shukla et al¹ coined the term miliarial gout when reporting the first known presentation of a patient with multiple tiny papules containing a white or creamlike substance scattered on an erythematous base. Other cases of miliarial gout have commonly involved the metacarpophalangeal joints of the hands, knees, abdomen, extensor forearms, and thighs.⁵ Similarly, our patient had disease involvement of the posterior upper arms and thighs. Furthermore, miliarial gout has been associated with carpal tunnel syndrome; monosodium urate crystal deposition in this space can lead to a clinical diagnosis of this condition.⁶

With a history of orthotopic heart transplant, it is possible that our patient’s immunocompromised status could have increased his susceptibility for the miliarial form of chronic tophaceous gout. Gout reportedly is the most common inflammatory arthritis in transplant recipients, with the highest prevalence following renal and heart transplantation.⁷ Pretransplant hyperuricemia is correlated with higher probabilities of posttransplant gout.⁸ In patients with a heart transplant, hyperuricemia may be due to diuretic use. Additionally, the presence of a gout diagnosis before transplant nearly triples the likelihood of posttransplant gout, which often is more severe than de novo gout, as seen in our patient. Calcineurin inhibitors, including tacrolimus, also can predispose patients to hyperuricemia and more severe forms of gout in the posttransplant phase by limiting fractional urate excretion within the first 3 months of therapy.⁷ Treatment with oral steroids, as in our patient, also has been identified as a potential inciting factor for the development of cutaneous tophaceous gout.⁹

Treatment with allopurinol and colchicine has been effective in patients with miliarial gout. Obesity and long-term treatment with furosemide (which our patient was not taking) are considered risk factors for the deposition of dermal and hypodermal urates.⁹ Our patient had a body mass index of 35 (≥30 indicates obesity); therefore, he also should be counseled on lifestyle modifications for optimal disease control.

The Diagnosis: Pleomorphic Lipoma

Pleomorphic lipoma is a rare, benign, adipocytic neoplasm that presents in the subcutaneous tissues of the upper shoulder, back, or neck. It predominantly affects men aged 50 to 70 years. Most lesions are situated in the subcutaneous tissues; few cases of intramuscular and retroperitoneal tumors have been reported.¹ Clinically, pleomorphic lipomas present as painless, well-circumscribed lesions of the subcutaneous tissue that often resemble a lipoma or occasionally may be mistaken for liposarcoma. Histopathologic examination of ordinary lipomas reveals uniform mature adipocytes. However, pleomorphic lipomas consist of a mixture of multinucleated floretlike giant cells, variable-sized adipocytes, and fibrous tissue (ropy collagen bundles) with some myxoid and spindled areas.^1,2 The most characteristic histologic feature of pleomorphic lipoma is multinucleated floretlike giant cells. The nuclei of these giant cells appear hyperchromatic, enlarged, and disposed to the periphery of the cell in a circular pattern. Additionally, tumors frequently contain excess mature dense collagen bundles that are strongly refractile in polarized light. Numerous mast cells are present. Atypical lipoblasts and capillary networks commonly are not visible in pleomorphic lipoma.³ The spindle cells express CD34 on immunohistochemistry. Loss of Rb-1 expression is typical.⁴

Dermatofibrosarcoma protuberans is a slow-growing soft tissue sarcoma that commonly begins as a pink or violet plaque on the trunk or upper limbs. Involvement of the head or neck accounts for only 10% to 15% of cases.⁵ This tumor has low metastatic potential but is highly infiltrative of surrounding tissues. It is associated with a translocation between chromosomes 22 and 17, leading to the fusion of the platelet-derived growth factor subunit β, PDGFB, and collagen type 1α1, COL1A1, genes.⁵ Clinically, patients often report that the lesion was present for several years prior to presentation with general stability in size and shape. Eventually, untreated lesions progress to become nodules or tumors and may even bleed or ulcerate. Histology reveals a storiform spindle cell proliferation throughout the dermis with infiltration into subcutaneous fat, commonly appearing in a honeycomblike pattern (Figure 1). Numerous histologic variants exist, including myxoid, sclerosing, pigmented (Bednar tumor), myoid, atrophic, or fibrosarcomatous dermatofibrosarcoma protuberans, as well as a giant cell fibroblastoma variant.⁶ These tumor subtypes can exist independently or in association with one another, creating hybrid lesions that can closely mimic other entities such as pleomorphic lipoma. The spindle cells stain positively for CD34. Treatment of these tumors involves complete surgical excision or Mohs micrographic surgery; however, recurrence is common for tumors involving the head or neck.⁵

Superficial angiomyxoma is a slow-growing papule that most commonly appears on the trunk, head, or neck in middle-aged adults. Occasionally, patients with Carney complex also can develop lesions on the external ear or breast.⁷ Histologically, superficial angiomyxoma is a hypocellular tumor characterized by abundant myxoid stroma, thin blood vessels, and small spindled and stellate cells with minimal cytoplasm (Figure 2).⁸ Superficial angiomyxoma and pleomorphic lipoma present differently on histology; superficial angiomyxoma is not associated with nuclear atypia or pleomorphism, whereas pleomorphic lipoma characteristically contains multinucleated floretlike giant cells and pleomorphism. Frequently, there also is loss of normal PRKAR1A gene expression, which is responsible for protein kinase A regulatory subunit 1-alpha expression.⁸

Multinucleate cell angiohistiocytoma is a rare benign proliferation that presents with numerous red-violet asymptomatic papules that commonly appear on the upper and lower extremities of women aged 40 to 70 years. Lesions feature both a fibrohistiocytic and vascular component.9 Histologic examination commonly shows multinucleated cells with angular outlining in the superficial dermis accompanied by fibrosis and ectatic small-caliber vessels (Figure 3). Although both pleomorphic lipoma and multinucleate cell angiohistiocytoma have similar-appearing multinucleated giant cells, the latter has a proliferation of narrow vessels in thick collagen bundles and lacks an adipocytic component, which distinguishes it from the former.¹⁰ Multinucleate cell angiohistiocytoma also is characterized by a substantial number of factor XIIIa–positive fibrohistiocytic interstitial cells and vascular hyperplasia.⁹

Nodular fasciitis is a benign lesion involving the rapid proliferation of myofibroblasts and fibroblasts in the subcutaneous tissue and most commonly is encountered on the extremities or head and neck regions. Many cases appear at sites of prior trauma, especially in patients aged 20 to 40 years. However, in infants and children the lesions typically are found in the head and neck regions.¹¹ Clinically, lesions present as subcutaneous nodules. Histology reveals an infiltrative and poorly circumscribed proliferation of spindled myofibroblasts associated with myxoid stroma and dense collagen depositions. The spindled cells are loosely associated, rendering a tissue culture–like appearance (Figure 4). It also is common to see erythrocyte extravasation adjacent to myxoid stroma.¹¹ Positive stains include vimentin, smooth muscle actin, and CD68, though immunohistochemistry often is not necessary for diagnosis.¹² There often is abundant mitotic activity in nodular fasciitis, especially in early lesions, and the differential diagnosis includes sarcoma. Although nodular fasciitis is mitotically active, it does not show atypical mitotic figures. Nodular fasciitis commonly harbors a gene translocation of the MYH9 gene’s promoter region to the USP6 gene’s coding region.¹³

The Diagnosis: Pleomorphic Lipoma

Pleomorphic lipoma is a rare, benign, adipocytic neoplasm that presents in the subcutaneous tissues of the upper shoulder, back, or neck. It predominantly affects men aged 50 to 70 years. Most lesions are situated in the subcutaneous tissues; few cases of intramuscular and retroperitoneal tumors have been reported.¹ Clinically, pleomorphic lipomas present as painless, well-circumscribed lesions of the subcutaneous tissue that often resemble a lipoma or occasionally may be mistaken for liposarcoma. Histopathologic examination of ordinary lipomas reveals uniform mature adipocytes. However, pleomorphic lipomas consist of a mixture of multinucleated floretlike giant cells, variable-sized adipocytes, and fibrous tissue (ropy collagen bundles) with some myxoid and spindled areas.^1,2 The most characteristic histologic feature of pleomorphic lipoma is multinucleated floretlike giant cells. The nuclei of these giant cells appear hyperchromatic, enlarged, and disposed to the periphery of the cell in a circular pattern. Additionally, tumors frequently contain excess mature dense collagen bundles that are strongly refractile in polarized light. Numerous mast cells are present. Atypical lipoblasts and capillary networks commonly are not visible in pleomorphic lipoma.³ The spindle cells express CD34 on immunohistochemistry. Loss of Rb-1 expression is typical.⁴

Dermatofibrosarcoma protuberans is a slow-growing soft tissue sarcoma that commonly begins as a pink or violet plaque on the trunk or upper limbs. Involvement of the head or neck accounts for only 10% to 15% of cases.⁵ This tumor has low metastatic potential but is highly infiltrative of surrounding tissues. It is associated with a translocation between chromosomes 22 and 17, leading to the fusion of the platelet-derived growth factor subunit β, PDGFB, and collagen type 1α1, COL1A1, genes.⁵ Clinically, patients often report that the lesion was present for several years prior to presentation with general stability in size and shape. Eventually, untreated lesions progress to become nodules or tumors and may even bleed or ulcerate. Histology reveals a storiform spindle cell proliferation throughout the dermis with infiltration into subcutaneous fat, commonly appearing in a honeycomblike pattern (Figure 1). Numerous histologic variants exist, including myxoid, sclerosing, pigmented (Bednar tumor), myoid, atrophic, or fibrosarcomatous dermatofibrosarcoma protuberans, as well as a giant cell fibroblastoma variant.⁶ These tumor subtypes can exist independently or in association with one another, creating hybrid lesions that can closely mimic other entities such as pleomorphic lipoma. The spindle cells stain positively for CD34. Treatment of these tumors involves complete surgical excision or Mohs micrographic surgery; however, recurrence is common for tumors involving the head or neck.⁵

Superficial angiomyxoma is a slow-growing papule that most commonly appears on the trunk, head, or neck in middle-aged adults. Occasionally, patients with Carney complex also can develop lesions on the external ear or breast.⁷ Histologically, superficial angiomyxoma is a hypocellular tumor characterized by abundant myxoid stroma, thin blood vessels, and small spindled and stellate cells with minimal cytoplasm (Figure 2).⁸ Superficial angiomyxoma and pleomorphic lipoma present differently on histology; superficial angiomyxoma is not associated with nuclear atypia or pleomorphism, whereas pleomorphic lipoma characteristically contains multinucleated floretlike giant cells and pleomorphism. Frequently, there also is loss of normal PRKAR1A gene expression, which is responsible for protein kinase A regulatory subunit 1-alpha expression.⁸

Multinucleate cell angiohistiocytoma is a rare benign proliferation that presents with numerous red-violet asymptomatic papules that commonly appear on the upper and lower extremities of women aged 40 to 70 years. Lesions feature both a fibrohistiocytic and vascular component.9 Histologic examination commonly shows multinucleated cells with angular outlining in the superficial dermis accompanied by fibrosis and ectatic small-caliber vessels (Figure 3). Although both pleomorphic lipoma and multinucleate cell angiohistiocytoma have similar-appearing multinucleated giant cells, the latter has a proliferation of narrow vessels in thick collagen bundles and lacks an adipocytic component, which distinguishes it from the former.¹⁰ Multinucleate cell angiohistiocytoma also is characterized by a substantial number of factor XIIIa–positive fibrohistiocytic interstitial cells and vascular hyperplasia.⁹

Nodular fasciitis is a benign lesion involving the rapid proliferation of myofibroblasts and fibroblasts in the subcutaneous tissue and most commonly is encountered on the extremities or head and neck regions. Many cases appear at sites of prior trauma, especially in patients aged 20 to 40 years. However, in infants and children the lesions typically are found in the head and neck regions.¹¹ Clinically, lesions present as subcutaneous nodules. Histology reveals an infiltrative and poorly circumscribed proliferation of spindled myofibroblasts associated with myxoid stroma and dense collagen depositions. The spindled cells are loosely associated, rendering a tissue culture–like appearance (Figure 4). It also is common to see erythrocyte extravasation adjacent to myxoid stroma.¹¹ Positive stains include vimentin, smooth muscle actin, and CD68, though immunohistochemistry often is not necessary for diagnosis.¹² There often is abundant mitotic activity in nodular fasciitis, especially in early lesions, and the differential diagnosis includes sarcoma. Although nodular fasciitis is mitotically active, it does not show atypical mitotic figures. Nodular fasciitis commonly harbors a gene translocation of the MYH9 gene’s promoter region to the USP6 gene’s coding region.¹³

The Diagnosis: Pleomorphic Lipoma

Pleomorphic lipoma is a rare, benign, adipocytic neoplasm that presents in the subcutaneous tissues of the upper shoulder, back, or neck. It predominantly affects men aged 50 to 70 years. Most lesions are situated in the subcutaneous tissues; few cases of intramuscular and retroperitoneal tumors have been reported.¹ Clinically, pleomorphic lipomas present as painless, well-circumscribed lesions of the subcutaneous tissue that often resemble a lipoma or occasionally may be mistaken for liposarcoma. Histopathologic examination of ordinary lipomas reveals uniform mature adipocytes. However, pleomorphic lipomas consist of a mixture of multinucleated floretlike giant cells, variable-sized adipocytes, and fibrous tissue (ropy collagen bundles) with some myxoid and spindled areas.^1,2 The most characteristic histologic feature of pleomorphic lipoma is multinucleated floretlike giant cells. The nuclei of these giant cells appear hyperchromatic, enlarged, and disposed to the periphery of the cell in a circular pattern. Additionally, tumors frequently contain excess mature dense collagen bundles that are strongly refractile in polarized light. Numerous mast cells are present. Atypical lipoblasts and capillary networks commonly are not visible in pleomorphic lipoma.³ The spindle cells express CD34 on immunohistochemistry. Loss of Rb-1 expression is typical.⁴

Dermatofibrosarcoma protuberans is a slow-growing soft tissue sarcoma that commonly begins as a pink or violet plaque on the trunk or upper limbs. Involvement of the head or neck accounts for only 10% to 15% of cases.⁵ This tumor has low metastatic potential but is highly infiltrative of surrounding tissues. It is associated with a translocation between chromosomes 22 and 17, leading to the fusion of the platelet-derived growth factor subunit β, PDGFB, and collagen type 1α1, COL1A1, genes.⁵ Clinically, patients often report that the lesion was present for several years prior to presentation with general stability in size and shape. Eventually, untreated lesions progress to become nodules or tumors and may even bleed or ulcerate. Histology reveals a storiform spindle cell proliferation throughout the dermis with infiltration into subcutaneous fat, commonly appearing in a honeycomblike pattern (Figure 1). Numerous histologic variants exist, including myxoid, sclerosing, pigmented (Bednar tumor), myoid, atrophic, or fibrosarcomatous dermatofibrosarcoma protuberans, as well as a giant cell fibroblastoma variant.⁶ These tumor subtypes can exist independently or in association with one another, creating hybrid lesions that can closely mimic other entities such as pleomorphic lipoma. The spindle cells stain positively for CD34. Treatment of these tumors involves complete surgical excision or Mohs micrographic surgery; however, recurrence is common for tumors involving the head or neck.⁵

Superficial angiomyxoma is a slow-growing papule that most commonly appears on the trunk, head, or neck in middle-aged adults. Occasionally, patients with Carney complex also can develop lesions on the external ear or breast.⁷ Histologically, superficial angiomyxoma is a hypocellular tumor characterized by abundant myxoid stroma, thin blood vessels, and small spindled and stellate cells with minimal cytoplasm (Figure 2).⁸ Superficial angiomyxoma and pleomorphic lipoma present differently on histology; superficial angiomyxoma is not associated with nuclear atypia or pleomorphism, whereas pleomorphic lipoma characteristically contains multinucleated floretlike giant cells and pleomorphism. Frequently, there also is loss of normal PRKAR1A gene expression, which is responsible for protein kinase A regulatory subunit 1-alpha expression.⁸

Multinucleate cell angiohistiocytoma is a rare benign proliferation that presents with numerous red-violet asymptomatic papules that commonly appear on the upper and lower extremities of women aged 40 to 70 years. Lesions feature both a fibrohistiocytic and vascular component.9 Histologic examination commonly shows multinucleated cells with angular outlining in the superficial dermis accompanied by fibrosis and ectatic small-caliber vessels (Figure 3). Although both pleomorphic lipoma and multinucleate cell angiohistiocytoma have similar-appearing multinucleated giant cells, the latter has a proliferation of narrow vessels in thick collagen bundles and lacks an adipocytic component, which distinguishes it from the former.¹⁰ Multinucleate cell angiohistiocytoma also is characterized by a substantial number of factor XIIIa–positive fibrohistiocytic interstitial cells and vascular hyperplasia.⁹

Nodular fasciitis is a benign lesion involving the rapid proliferation of myofibroblasts and fibroblasts in the subcutaneous tissue and most commonly is encountered on the extremities or head and neck regions. Many cases appear at sites of prior trauma, especially in patients aged 20 to 40 years. However, in infants and children the lesions typically are found in the head and neck regions.¹¹ Clinically, lesions present as subcutaneous nodules. Histology reveals an infiltrative and poorly circumscribed proliferation of spindled myofibroblasts associated with myxoid stroma and dense collagen depositions. The spindled cells are loosely associated, rendering a tissue culture–like appearance (Figure 4). It also is common to see erythrocyte extravasation adjacent to myxoid stroma.¹¹ Positive stains include vimentin, smooth muscle actin, and CD68, though immunohistochemistry often is not necessary for diagnosis.¹² There often is abundant mitotic activity in nodular fasciitis, especially in early lesions, and the differential diagnosis includes sarcoma. Although nodular fasciitis is mitotically active, it does not show atypical mitotic figures. Nodular fasciitis commonly harbors a gene translocation of the MYH9 gene’s promoter region to the USP6 gene’s coding region.¹³