Dermatitis herpetiformis is an autoimmune condition characterized by pruritic, recurrent papulovesicular lesions. The lesions characteristically are bilateral and symmetric herpetiform vesicles which involve the extensor surfaces, elbows, knees, upper back and buttocks.
Biopsy specimens show neutrophils and fibrin in the dermal papillae along with edematous changes. Papillary microabscesses form and eventually progress to subepidermal vesicles. The gold standard for diagnosis is demonstration of granular IgA in the dermal papillae on direct immunofluorescence from specimens of normal skin taken at the periphery of the lesions.
Persons of European descent are most often affected and there is an association with gluten-sensitive enteropathy (celiac disease). There is also an association with thyroiditis, hypothyroidism, gastrointestinal lymphomas, non-Hodgkin's lymphomas, and pernicious anemia.
A gluten-free diet may result in resolution of symptoms if celiac disease is the underlying etiology. Further therapy may be offered in the form of dapsone (25-400 mg/day in divided doses) plus or minus cimetidine, which helps reduce its adverse hematologic effects, in more refractory cases. Other potential therapies include sulfapyridine, colchicine, cyclosporine, and prednisone.