Leg rash

The appearance and location of this rash are classic signs for necrobiosis lipoidica, a chronic granulomatous skin disease commonly associated with diabetes. The patient’s initial hemoglobin A1c was 12.4%, confirming a diagnosis of type 2 diabetes, and a punch biopsy of the lesion demonstrated a broad zone of necrobiosis in the mid to lower dermis and a chronic inflammatory infiltrate, including plasma cells.

Necrobiosis lipoidica is rare, typically affects middle-aged adults, and is more common in women than in men.¹ Although commonly associated with diabetes (hence the historical name necrobiosis lipoidica diabeticorum), a significant number of cases occur in patients without diabetes.² The pathogenesis is not fully understood. The condition first appears as asymptomatic yellow to red-brown papules and plaques, most commonly on the anterior legs. The lesions then flatten over time, forming broad, yellow-pink patches and plaques.^1,2

Generally, the diagnosis can be made clinically but, if uncertain, a punch biopsy is the preferred technique for confirmation. The differential diagnosis includes chronic cutaneous lupus erythematosus (LE), sarcoidosis, and dermatophytosis. Although the appearance of lesions associated with LE or sarcoidosis can vary, neither one manifests with the yellow coloring seen here. Dermatophytosis typically demonstrates scale and pruritus with an active border; viewing a potassium hydroxide preparation of a skin scraping is usually sufficient to make a diagnosis.

Treatment for necrobiosis lipoidica includes counseling patients to avoid trauma to the affected areas, high-potency topical corticosteroids, and photodynamic therapy.³ Often, lesions are permanent.

For this patient’s diabetes treatment, she was prescribed metformin and insulin glargine and counseled extensively on weight loss, regular exercise, and appropriate diet adjustments. The rash was treated topically with triamcinolone 0.1% cream bid. At her 4-month follow-up, the patient’s hemoglobin A1c value had dropped to 5.4%, and the rash had become less prominent and widespread. The patient was pleased with the cosmetic outcome and declined referral to a dermatologist for further treatment.

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Photo and text courtesy of Samuel Dickmann, MD, and James Medley, MD, University of Florida College of Medicine, Gainesville.

The appearance and location of this rash are classic signs for necrobiosis lipoidica, a chronic granulomatous skin disease commonly associated with diabetes. The patient’s initial hemoglobin A1c was 12.4%, confirming a diagnosis of type 2 diabetes, and a punch biopsy of the lesion demonstrated a broad zone of necrobiosis in the mid to lower dermis and a chronic inflammatory infiltrate, including plasma cells.

Necrobiosis lipoidica is rare, typically affects middle-aged adults, and is more common in women than in men.¹ Although commonly associated with diabetes (hence the historical name necrobiosis lipoidica diabeticorum), a significant number of cases occur in patients without diabetes.² The pathogenesis is not fully understood. The condition first appears as asymptomatic yellow to red-brown papules and plaques, most commonly on the anterior legs. The lesions then flatten over time, forming broad, yellow-pink patches and plaques.^1,2

Generally, the diagnosis can be made clinically but, if uncertain, a punch biopsy is the preferred technique for confirmation. The differential diagnosis includes chronic cutaneous lupus erythematosus (LE), sarcoidosis, and dermatophytosis. Although the appearance of lesions associated with LE or sarcoidosis can vary, neither one manifests with the yellow coloring seen here. Dermatophytosis typically demonstrates scale and pruritus with an active border; viewing a potassium hydroxide preparation of a skin scraping is usually sufficient to make a diagnosis.

Treatment for necrobiosis lipoidica includes counseling patients to avoid trauma to the affected areas, high-potency topical corticosteroids, and photodynamic therapy.³ Often, lesions are permanent.

For this patient’s diabetes treatment, she was prescribed metformin and insulin glargine and counseled extensively on weight loss, regular exercise, and appropriate diet adjustments. The rash was treated topically with triamcinolone 0.1% cream bid. At her 4-month follow-up, the patient’s hemoglobin A1c value had dropped to 5.4%, and the rash had become less prominent and widespread. The patient was pleased with the cosmetic outcome and declined referral to a dermatologist for further treatment.

‌

Photo and text courtesy of Samuel Dickmann, MD, and James Medley, MD, University of Florida College of Medicine, Gainesville.

The appearance and location of this rash are classic signs for necrobiosis lipoidica, a chronic granulomatous skin disease commonly associated with diabetes. The patient’s initial hemoglobin A1c was 12.4%, confirming a diagnosis of type 2 diabetes, and a punch biopsy of the lesion demonstrated a broad zone of necrobiosis in the mid to lower dermis and a chronic inflammatory infiltrate, including plasma cells.

Necrobiosis lipoidica is rare, typically affects middle-aged adults, and is more common in women than in men.¹ Although commonly associated with diabetes (hence the historical name necrobiosis lipoidica diabeticorum), a significant number of cases occur in patients without diabetes.² The pathogenesis is not fully understood. The condition first appears as asymptomatic yellow to red-brown papules and plaques, most commonly on the anterior legs. The lesions then flatten over time, forming broad, yellow-pink patches and plaques.^1,2

Generally, the diagnosis can be made clinically but, if uncertain, a punch biopsy is the preferred technique for confirmation. The differential diagnosis includes chronic cutaneous lupus erythematosus (LE), sarcoidosis, and dermatophytosis. Although the appearance of lesions associated with LE or sarcoidosis can vary, neither one manifests with the yellow coloring seen here. Dermatophytosis typically demonstrates scale and pruritus with an active border; viewing a potassium hydroxide preparation of a skin scraping is usually sufficient to make a diagnosis.

Treatment for necrobiosis lipoidica includes counseling patients to avoid trauma to the affected areas, high-potency topical corticosteroids, and photodynamic therapy.³ Often, lesions are permanent.

For this patient’s diabetes treatment, she was prescribed metformin and insulin glargine and counseled extensively on weight loss, regular exercise, and appropriate diet adjustments. The rash was treated topically with triamcinolone 0.1% cream bid. At her 4-month follow-up, the patient’s hemoglobin A1c value had dropped to 5.4%, and the rash had become less prominent and widespread. The patient was pleased with the cosmetic outcome and declined referral to a dermatologist for further treatment.

‌

Photo and text courtesy of Samuel Dickmann, MD, and James Medley, MD, University of Florida College of Medicine, Gainesville.