PTU-induced ANCA-positive vasculitis: an innocent or a life-threatening adverse effect?

Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitides are rare, but they can be triggered by chemicals, infections and drugs; among them, antithyroid drugs are common. Autoimmune disorders, such as vasculitis, are unusual, but serious complications of antithyroid therapy. Both propylthiouracil (PTU) and methimazole may induce ANCA-associated vasculitis. PTU-induced vasculitides may have different organ involvement patterns. Herein, we report four cases with ANCA-associated vasculitis with different clinical manifestations.