RESUMEN
OBJECTIVE: To describe the clinical and serologic abnormalities in 6 patients who presented with retiform purpura and extensive cutaneous necrosis after exposure to levamisole-adulterated cocaine. METHODS: All patients were evaluated at San Francisco General Hospital or the University of California San Francisco Medical Center. Each underwent standard screening for substances of abuse and had urine tested for the presence of levamisole by liquid chromatography tandem mass spectrometry. Routine laboratory, autoantibody, and antiphospholipid antibody testing was performed in the hospitals' clinical or reference laboratories. Testing for atypical antineutrophil cytoplasmic antibodies (ANCAs) was performed separately using commercially available enzyme-linked immunosorbent assay kits. RESULTS: The patients were women ages 39-50 years who presented with retiform purpura and cutaneous necrosis. Skin biopsies revealed a predominantly small-vessel thrombotic vasculopathy with varying degrees of vasculitis. Four patients were neutropenic. All tested positive for lupus anticoagulant, had IgM antibodies to cardiolipin, and tested strongly positive for ANCAs in a perinuclear pattern by immunofluorescence. Each patient had antibodies to multiple components of neutrophil granules, including neutrophil elastase, lactoferrin, cathepsin G, proteinase 3, and myeloperoxidase. CONCLUSION: Rheumatologists should be aware of this distinctive form of necrotic purpura, its associated autoantibodies, and its link to levamisole-adulterated cocaine.