Levamisole-induced vasculitis is characterized by a painful, purpuric rash in a retiform or stellate pattern with or without central necrosis that commonly involves the trunk, extremities, digits, distal nose, cheeks, and ear helices. This clinical syndrome is associated with the use of levamisole-adultered cocaine. Histologic findings for levamisole-induced vasculitis are not disease specific but may include leukocytoclastic vasculitis, microvascular thrombosis, and panniculitis. Laboratory findings of levamisole-induced toxicity include agranulocytosis, neutropenia, hepatotoxicity, glomerulonephritis, pulmonary hemorrhage, and positive p-ANCA, c-ANCA tests, ANA, or lupus anticoagulant. The differential diagnosis for levamisole-induced vasculitis includes leukocytoclastic vasculitis, drug reaction, cryoglobulinemia, idiopathic thrombocytopenic purpura, granulomatosis with polyangiitis, Churg-Strauss syndrome, and polyarteritis nodosa. Levamisole-induced vasculitis typically resolves spontaneously with cessation of cocaine use however; recurrence is common following re-exposure.
Painful Retiform Purpura with Cutaneous Necrosis
