Polymyositis/dermatomyositis associated with dermatitis herpetiformis.

We describe 2 patients with dermatitis herpetiformis who developed polymyositis/dermatomyositis. On HLA typing, both patients were found to be HLA-B8, DR3 positive. The concurrence of these two relatively rare diseases, both associated with immunologic abnormalities, further supports the role of autoimmunity in their pathogenesis and indicates a possible common genetic basis. It also suggests that myositis may be more common in patients with dermatitis herpetiformis than in the general population.