What is erythema elevatum diutinum (EED)?
EED is a form of LCV limited to the skin. The lesions have a characteristic distribution in that they involve the skin over the extensor surface of joints (especially knuckles, knees, and buttocks) symmetrically. They start as pink/yellow papules or plaques and later become red/purple nodules. Biopsy shows LCV with fibrinoid necrosis. Direct immunofluorescence is nonspecific. EED has been associated with connective tissue diseases, infections, and paraproteinemias, especially IgA. Patients respond dramatically to dapsone or sulfapyridine, but lesions recur on discontinuation.
