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 disorder of large arteries, in particular the aorta, characterized by an accumulation of basophilic ground substance in the media with cyst-like lesions associated with degenerative changes of collagen, elastin and the vascular smooth muscle cells.
Dermatitis herpetiformis and SLE were diagnosed in a 15-year-old girl with Marfan's syndrome who died of cardiac tamponade secondary to cystic medial necrosis of the ascending aorta.