Necrotizing vasculitis in a patient affected by autoimmune hyperthyroidism treated with propylthiouracil

Necrotizing vasculitis is a complex phenomenon because of an inflammation of small and larger vessels with polymorph infiltration within the vessel walls and leukocytoclasis, occurring in several autoimmune diseases. Propylthiouracil (PTU) is a medication commonly used to treat hyperthyroidism, but it is associated with various rare side effects, such as antineutrophil cytoplasm antibody-positive vasculitis. In the last decades, multiple cases of PTU causing antineutrophilic cytoplasmic antibody have been reported, some of them fatal. The present authors report the case of a 34-year-old Caucasian female affected by autoimmune hyperthyroidism treated with PTU, presenting an antineutrophil cytoplasm antibody-positive necrotizing vasculitis, with high levels of anticardiolipin antibodies that involved the upper arms and buttocks. The clinical manifestations improved after discontinuing of PTU and immunosuppressant treatment.