herpetiformis

Dermatitis herpetiformis is a chronic, intensely pruritic vesiculopapular eruption characterized by grouped vesicles and wheals, typically on extensor surfaces such as the elbows, knees, buttocks, shoulders, and scalp. The rash often appears in symmetrical clusters and is accompanied by severe itch and burning. Onset typically occurs in adolescence to middle age, and the condition frequently follows a relapsing course. Dermatitis herpetiformis is the cutaneous manifestation most strongly associated with gluten sensitivity and celiac disease.

Pathophysiology and associations: Dermatitis herpetiformis arises from an autoimmune process in which IgA antibodies are deposited in the dermal papillae. This leads to the formation of subepidermal vesicles and pruritus. The condition is strongly linked to celiac disease and gluten sensitivity, with genetic predisposition commonly involving HLA-DQ2 or DQ8. Many patients have or will develop intestinal involvement consistent with celiac disease.

Diagnosis: Diagnosis is supported by skin biopsy with direct immunofluorescence showing granular IgA deposits at the tips of dermal papillae. Serologic testing may reveal positive antibodies to tissue transglutaminase (tTG) or endomysial antibodies, and intestinal biopsy can show enteropathy consistent with celiac disease.

Treatment and prognosis: Dapsone provides rapid relief of itching and lesions, but does not address the underlying gluten sensitivity. A strict gluten-free diet is essential for long-term control and may allow reduction or discontinuation of dapsone over time. Regular monitoring for adverse effects of dapsone (such as hematologic or metabolic complications) and for associated celiac disease is recommended. With adherence to a gluten-free diet, the skin disease often improves and may remit, though flares can occur with gluten exposure.