A 25-year-old woman comes to the physician with a rash on her buttocks. The lesions began 10 days ago and are associated with intense itching and burning. She has attempted treatment with cool compresses and calamine lotion without relief. The patient has had occasional diarrhea and unintentional weight loss over the past few months. Her medical history is otherwise unremarkable. Her temperature is 37.1 C (98.8 F), blood pressure is 117/76 mm Hg, pulse is 82/min, and respirations are 14/min. The skin lesions are shown in the image below. Which of the following is the most likely diagnosis of this patient's rash?

Question

A 25-year-old woman comes to the physician with a rash on her buttocks.  The lesions began 10 days ago and are associated with intense itching and burning.  She has attempted treatment with cool compresses and calamine lotion without relief.  The patient has had occasional diarrhea and unintentional weight loss over the past few months.  Her medical history is otherwise unremarkable.  Her temperature is 37.1 C (98.8 F), blood pressure is 117/76 mm Hg, pulse is 82/min, and respirations are 14/min.  The skin lesions are shown in the image below.  Which of the following is the most likely diagnosis of this patient's rash?

Quizplus · Accepted Answer

Dermatitis herpetiformis (DH) causes intensely pruritic erythematous papules, vesicles, and bullae that occur symmetrically in grouped ("herpetiform") clusters on the extensor surfaces of the elbows, knees, back, and buttocks. DH represents an autoimmune dermal reaction due to dietary gluten and is commonly associated with celiac disease (the likely cause of this patient's diarrhea and weight loss), although it may precede the gastrointestinal manifestations. Skin biopsy in DH shows subepidermal microabscesses (blisters) at the tips of the dermal papillae; immunofluorescence studies show deposits of anti-epidermal transglutaminase IgA in the dermis. Initial treatment includes dapsone, which has anti-inflammatory and immunomodulatory properties and provides rapid relief of symptoms. Long-term management requires a gluten-free diet. microabscesses immunofluorescence (Choice A) Bullous pemphigoid is an autoimmune disease that most commonly affects individuals age >60. Patients have a variable prodrome of eczematous or urticarial lesions and subsequently develop tense bullae and plaques affecting the flexural areas, groin, or axilla. (Choice C) Erythema multiforme is an inflammatory disorder characterized by erythematous papules and plaques that evolve into target lesions. plaques (Choice D) Reactivation of herpes zoster causes erythematous vesicles and ulcers in a dermatomal distribution, and bilateral symptoms are rare. (Choice E) Pemphigus vulgaris is an autoimmune disorder characterized by painful, flaccid bullae, mucosal erosions, and separation of the epidermis from the dermis on light friction. The roof of the bullous lesions is fragile and rapidly desquamates, leaving raw ulcers. mucosal erosions ulcers (Choice F) Psoriasis is a chronic inflammatory disorder that primarily affects the extensor surfaces of the elbows and knees. Lesions appear as red, sharply demarcated, scaling papules that coalesce to form oval plaques. plaques Educational objective: Dermatitis herpetiformis is an autoimmune dermal reaction due to dietary gluten and is commonly associated with celiac disease. It presents with clusters of pruritic papules and vesicles on the elbows, knees, back, and buttocks. Management includes dapsone and a gluten-free diet. References: The diagnosis and treatment of dermatitis herpetiformis. (http://www.ncbi.nlm.nih.gov/pubmed/25999753)

A 25-Year-Old Woman Comes to the Physician with a Rash