Erythema elevatum diutinum: an "idiopathic" case.

Erythema elevatum diutinum (EED) is a rare condition with an unclear pathogenesis. Initially classified within neutrophilic dermatoses, it is now considered as a leukocytoclastic vasculitis accordingly to its histopathologic pattern. Several clinical presentations as well as many associated diseases are reported in the literature. We report a new case of EED in a 58-year-old man who presented with a three-month history of plaques and nodules on the extensor surfaces of hands, elbows, knees, ankles, forearms, and buttocks. Histology showed a leucocytoclastic vasculitis, suggestive of the diagnosis of EED. Screening for an associated pathology, namely a paraproteinemia or a solid cancer, was negative. Treatment with dapsone leads to amelioration within few weeks.