Cytoplasmic Pattern Anti-neutrophil Cytoplasmic Antibody (cANCA)-positive Cutaneous Leukocytoclastic Vasculitis Induced by Propylthiouracil: A Case Report

Abstract

Propylthiouracil (PTU) is a medication commonly used to treat hyperthyroidism, but it has various rare side effects such as anti-neutrophil cytoplasmic antibodies (ANCA)- associated vasculitis (AAV). In the last decades, multiple cases of PTU-induced AAV have been reported, some being fatal. While AAV is primarily related to perinuclear-staining ANCA/anti-myeloperoxidase (pANCA/anti-MPO), it can occur to a lesser extent in association with cytoplasmic staining ANCA/ proteinase 3 (cANCA/PR3). A case is presented of a 62-year-old female with a history of hyperthyroidism due to toxic multinodular goiter treated with a standard dose of PTU. Approximately 3 years after starting therapy, she noticed formation of skin ulcerations on both of her ear lobes, nose and bilateral limbs. Detailed hospital work-up detected cANCA positivity. Biopsy of the affected skin revealed leukocytoclastic vasculitis and additional tests excluded systemic vasculitis. The patient was diagnosed as PTU-induced vasculitis, a form of drug-induced vasculitis. Although clinical manifestations improved slightly after total thyroidectomy, the patient could not be saved because of the fulminant course of infected and disseminated skin ulcers. Conclusion: PTU is one of the causes of AAV. However, the presence of cANCA positivity when pANCA is negative in PTU-induced AAV is extremely rare. Here, we present a rather unusual case of PTU-induced AAV associated with cANCA.