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/antimyeloperoxidase (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. 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

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