Dermatitis herpetiformis.

Dermatitis herpetiformis (DH) is an autoimmune bullous disease, which represents the cutaneous manifestation of gluten sensitivity, in the setting of celiac disease. Although classical DH is characterized clinically by grouped, vesicles on an erythematous base, primary lesions often are absent owing to the intense, associated pruritus. Instead, many cases present only with erythematous erosions with numerous overlying excoriations. As in celiac disease, the core pathogenic mechanisms of DH are likely mediated by immunoglobulin A class autoantibodies against one of several transglutaminase enzymes. As the production of these autoantibodies is directly correlated with gastrointestinal exposure to gliadin, which is an alcohol-soluble fraction of gluten, a gluten-free diet represents the cornerstone of a DH management regimen. In cases refractory to dietary management alone, dapsone is the first-line agent for the treatment of DH, although many other agents have been anecdotally reported as effective.