Erythema elevatum diutinum: cutaneous vasculitis, impaired clot lysis, and response to phenformin.

Erythema elevatum diutinum consists of chronic, often painful, predominantly acral skin nodules and plaques, associated with an underlying cutaneous vasculitis. A patient with this disorder is described, who had an elevated sedimentation rate, positive antinuclear factor, impaired clot lysis, and dramatic fibrin deposition in skin vessel walls. A variety of treatments were without benefit in this case as in most others, but phenformin produced marked improvement for periods of 11 and 16 months on two occasions. Protection of the lesions from minor trauma is also important.