Dermatitis herpetiformis

Case history

A 39-year-old man presents with a 1-year history of pruritic papules, erythema, and scratching lesions on the extensor aspects of his upper and lower limbs. He occasionally reports mild abdominal bloating but is otherwise healthy. Following a clinical diagnosis of prurigo subacuta, he was repeatedly treated with antihistamines and topical corticosteroids, together with short cycles of systemic corticosteroids, without significant improvement. His sister has a diagnosis of coeliac disease and he has been following a partial gluten-free diet for a few weeks without significant improvement. Serological screening for coeliac disease reveals the presence of immunoglobulin A (IgA) anti-tissue transglutaminase antibodies (36.4 UI/mL). A biopsy of lesional skin for histopathology shows perivascular lymphocytic infiltrate and the presence of scattered neutrophil granulocytes at the dermal papillae, while a biopsy on perilesional skin for direct immunofluorescence microscopy reveals granular IgA deposits at the tips of dermal papillae and along the dermal-epidermal junction.

Other presentations

Dermatitis herpetiformis usually affects adults; however, the disease may less commonly start in childhood.[4]Antiga E, Verdelli A, Calabrò A, et al. Clinical and immunopathological features of 159 patients with dermatitis herpetiformis: an Italian experience. G Ital Dermatol Venereol. 2013 Apr;148(2):163-9. http://www.ncbi.nlm.nih.gov/pubmed/23588141?tool=bestpractice.com Dermatitis herpetiformis typically presents with grouped vesicles and small blisters occurring on the elbows, knees, and buttocks, but it may also present with atypical cutaneous manifestations, including hyperkeratotic lesions of palms and soles, leukocytoclastic vasculitis-like lesions, prurigo-like lesions, and other lesions that can mimic other more common pruritic skin diseases such as atopic dermatitis. Sometimes, only itching and scratching lesions are present. Some patients present with gastrointestinal symptoms, although the majority do not show signs of bowel involvement.

Asian patients, particularly from Japan (where the condition is more rarely seen than in western countries), more often have atypical presentations of dermatitis herpetiformis, with sparing of the typical sites (such as elbows, knees, shoulders, and scalp), frequent involvement of the extremities, lack of association with coeliac disease, and absence of coeliac-specific autoantibodies (e.g., immunoglobulin A-tissue transglutaminase and endomysial antibody).