[Dermatitis herpetiformis: a review].

BACKGROUND

Dermatitis herpetiformis (DH) is a rare auto-immune bullous disease characterized by its almost constant association to gluten sensitivity.

OBJECTIVE

Review of literature about epidemiology, physiopathology, clinical data and treatment of DH.

METHODS

Research on Medline and Embase database without any time limit until April 2010. Because of the lack of randomized therapeutic trials in DH, retrospective series and case reports have been analyzed.

RESULTS

DH is related to auto-antibodies against epidermal transglutaminase, which belongs to the same family as tissue transglutaminase, the auto-antigen of celiac disease. Physiopathology is complex, occurring in HLA DQ2 or DQ8 predisposed patients, and implies gluten, immunological reaction in the intestinal wall then in the skin. DH and celiac disease may be encountered in the same family. DH is characterized by a very pruritic microvesicular eruption typically located on elbows, knees and buttocks. Digestive manifestations of celiac disease occur in 15% of cases. Direct immunofluorescence is necessary to confirm the diagnosis, showing granular IgA±C3 deposits in the papillary dermis. Circulating IgA and IgG antiendomysium and antitransglutaminase antibodies are detected in almost all patients at the acute phase and follow the clinical course of the disease. Gastro-intestinal endoscopy with multiple duodenal biopsies shows partial or complete villous atrophy in two thirds of cases, intraepithelial lymphocyte infiltrate in the other cases. Other auto-immune diseases may be associated in 10-20% of cases. The main long-term risk is the occurrence of T or B nodal or intestinal tract lymphoma in 2% of cases (relative risk close to 6 in several studies, but not admitted by all authors), especially if adherence to gluten-free diet is not strict. Treatment is based on dapsone, which is quickly efficient on cutaneous manifestations, but not on the digestive involvement and on strict and definitive gluten-free diet, which cures villous atrophy and reduces the risk of lymphoma.

CONCLUSION

DH is associated to a gluten enteropathy and its physiopathology is better known. Even if the risk of secondary lymphoma seems little, most of the authors recommend a definitive gluten-free diet.