Necrotizing vasculitis in a patient affected by autoimmune hyperthyroidism treated with propylthiouracil Angela Antonucci*, Federico Bardazzi*, Ivano Iozzo†& Annalisa Patrizi* Departments of *Dermatology and † Plastic Surgery, University of Bologna, Bologna, Italy ABSTRACT: 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 hyper- thyroidism, 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 cyto- plasmic 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. KEYWORDS: ANCA, autoimmune hyperthyroidism, necrotizing vasculitis, propylthiouracil Introduction Thioazoles have become useful drugs for the treat- ment of autoimmune hyperthyroidism, but they have rarely been associated with the development of drug-induced vasculitis (1). Antineutrophil cyto- plasm antibody (ANCA) positivity often occurs in patients treated with propylthiouracil (PTU), and it is strictly correlated with the development of vasculitis (2). Autoimmune hyperthyroidism may be itself associated with other autoimmune manifestations, and often, it can produce a hypercoagulable state (3), with high levels of anti- cardiolipin antibodies and lupus anticoagulant positivity. Case report A 34-year-old Caucasian female came to our day hospital service presenting a rapid onset of hemor- rhagic skin lesions involving both upper arms and buttocks. The lesions were asymptomatic. She had a history of autoimmune hyperthyroidism diag- nosed 5 years previously and, for 2 years, had been undergoing treatment with PTU because of an allergic reaction to methimazol. Clinical examina- tion revealed four large areas of livedo and tender, nonraised hemorrhagic areas covering the upper arms and buttocks (FIG. 1). The lesions doubled in size over the next 24 hours with areas of Address correspondence and reprint requests to: Angela Antonucci, MD, Department of Dermatology, Via Massarenti 1, 40138 Bologna, Italy, or email: av_antonucci@yahoo.it. Conflict of interest and funding sources: None. S41 Dermatologic Therapy, Vol. 23, 2010, S41–S43 Printed in the United States · All rights reserved © 2010 Wiley Periodicals, Inc. DERMATOLOGIC THERAPY ISSN 1396-0296