Pyoderma gangrenosum with secondary pyarthrosis following propylthiouracil.

The association of pyoderma gangrenosum and arthritio symptoms is well documented. We present a rarely reported variant of this in a 44-year-old woman with pyoderma gangrenosum and bilateral large purulent effusions of her knees. She had no evidence of underlying rheumatoin arthritis or a specific seronegative apondyloarthropathy, Of note she had a history of Graves' disease for which she had been treated with propylthiauracil for 5 years and on investigation at this presentation had a markedly elevated perinuclear antineutrophil cytoplasm antibody (P-ANCA) level with specificities for IgM myeloperoxidase, IgG elastase and IgG lactoferrin. We believe this patient had pyoderns gaogrenosuan with secondary sterile pyarthrosis and a P-ANCA precipitated by propylthiouracil.