Perinuclear antineutrophilic cytoplasmic antibody-positive cutaneous polyarteritis nodosa associated with minocycline therapy for acne vulgaris

Minocycline is an oral antibiotic widely used fur the long-term treatment o f acne vulgaris. Unusual side effects of this medication include two overla pping autoimmune syndromes: drug-induced lupus and autoimmune hepatitis. In addition, in a few patients livedo reticularis or subcutaneous nodules hav e developed in association with arthritis and serum perinuclear antineutrop hil cytoplasmic antibodies (P-ANCA) during long-term minocycline therapy. W e report the cases of two young women receiving long-term minocycline thera py (>3 years) in whom P-ANCA-positive cutaneous polyarteritis nodosa develo ped. Both patients presented with a violaceous reticulated pattern on the l ower extremities. Histologic examination of biopsy specimens from a reticul ated area and a subcutaneous nodule showed necrotizing vasculitis of medium -sized arteries in the deep dermis, consistent with the diagnosis of polyar teritis nodosa. The cutaneous lesions rapidly resolved on discontinuation o f minocycline and initiation of prednisone therapy. A high index of suspici on and testing for antineutrophil cytoplasmic antibody in addition to the s tandard antinuclear antibody panel can facilitate diagnosis of minocycline- related autoimmune disorders.