A chronic autoimmune subepidermal bullous disease characterized by grouped pruritic lesions such as papules, urticarial plaques, erythema, and herpetiform vesiculae, with a predominantly symmetrical distribution on extensor surfaces of the elbows (90%), knees (30%), shoulders, buttocks, sacral region, and face of children and adults. Erosions, excoriations and hyperpigmentation usually follow. It may also appear as a consequence of gluten intolerance.

A malignant tumor arising from epithelial cells. Carcinomas that arise from glandular epithelium are called adenocarcinomas, those that arise from squamous epithelium are called squamous cell carcinomas, and those that arise from transitional epithelium are called transitional cell carcinomas (NCI Thesaurus).