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Abstract

Cutaneous and mucosal disorders associated with cocaine use may closely mimic granulomatosis with polyangiitis (GPA) both clinically and serologically; misdiagnosis may risk unnecessary immunosuppression. We present a series of 3 patients with clinical and pathologic features of cocaine-associated plasma cell orificial mucositis (CAPCOM) and describe its relationship to and distinction from cocaine-induced midline destructive lesions (CIMDL).  A 47-year-old woman presented with painful, vegetative plaques of the infranasal upper lip. Indirect immunofluorescence (IIF) demonstrate a cytoplasmic antineutrophil cyctoplasmic (c-ANCA) pattern at 1:80; antigen-specific ELISA was PR3-positive and MPO-negative. Urine toxicology was positive for cocaine metabolites. In a 60-year-old woman with painful vegetative plaques affecting the nares and upper cutaneous lip, IIF was negative for ANCAs, but ELISA was positive for anti-PR3 antibodies. Anamnesis confirmed cocaine nasal insufflation. A 55-year-old man presented with vegetative plaques of the upper cutaneous lip and nasolabial folds; IIF demonstrated a c-ANCA pattern, and the patient was ultimately treated for GPA. In all patients, histopathology demonstrated consistent features: marked epidermal hyperplasia, variable intraepidermal pustules with eosinophils, and a brisk mixed dermal infiltrate with many eosinophils and plasma cells. CAPCOM is an emerging entity of increasing significance given the widespread use of cocaine and is a hypersensitivity reaction due to an unknown allergen. While CAPCOM and CIMDL are often concurrent findings, CIMDL demonstrates extensive necrosis and is due to ischemia. GPA can be misdiagnosed in patients with CAPCOM or CIMDL due to overlapping serologic findings, but is distinguished by pathologic features of vasculitis or granulomas and systemic findings.