Quinidine-induced vasculitis.

Four patients developed nonthrombocytopenic purpura two to three weeks after initiation of quinidine therapy. The skin lesions disappeared and did not recur after cessation of quinidine therapy. Histologic examination revealed leukocytoclastic vasculitis with deposition of C3, IgA, and/or IgM in the small dermal vessels. Since quinidine purpura is usually associated with thrombocytopenia, the possibility of leukocytoclastic vasculitis as an additional cause of purpura is stressed.