Antithyroid Drugs Induced Vasculitis

The aim of this article is to review current information documented on antithyroid drug induced vasculitis.

MEDLINE was searched for studies between 1960 and 2009 with the key words “antithyroid drugs and vasculitis”, “antithyroid drugs and diffuse alveolar hemorrhage”, and “antithyroid drugs and glumerolonephritis”.

Ninety-two articles met the selection criteria. The data obtained showed that 15 to 46% of patients treated with propylthiouracil (PTU) developed anti-neutrophil cytoplasmic antibody (ANCA), in contrast to 0 to 3% of the patients treated with methimazole (MMI), the former being the most often reported for causing vasculitis, a disease seen most commonly in association with Graves’ disease. Signs of PTU-induced vasculitis include fever, malaise, anemia, lymphadenopathy, skin lesions, arthralgia, hematuria/proteinuria, diffuse alveolar hemorrhage (DAH), pleural effusion, and crescentic glomerulonephritis. Once PTU-induced vasculitis is determined, the simple withdrawal of PTU usually causes resolution of the symptoms within 1-4 weeks. Overall prognosis of antithyroid drug-induced vasculitis is much better than that of primary vasculitis.

Antithyroid medications such as PTU can induce (ANCA)-associated vasculitis. Its pathogenesis might be multifactorial. Diagnosis is based on the relationship between clinical vasculitis, and the antithyroid drugs prescribed, and the excluding of any other medical states that mimic vasculitis. After the diagnosis, antithyroid drugs should be discontinued immediately, and the prognosis is usually good.