A case of propylthiouracil-induced pyoderma gangrenosum associated with antineutrophil cytoplasmic antibody.

A 27-year-old woman who had been receiving propylthiouracil for 2 years for Graves' disease presented with painful ulceration on the lower limbs which had first appeared 2 weeks previously. Well-circumscribed hemorrhagic ulcerations with ragged borders were noted on both legs. Skin biopsy demonstrated a florid neutrophilic infiltrate and evidence of leukocytoclasis around small blood vessels in the papillary dermis compatible with the diagnosis of pyoderma gangrenosum. A highly positive perinuclear pattern of antineutrophil cytoplasmic antibody with specificities for IgM myeloperoxidase was observed. The authors think that propylthiouracil is associated with the occurrence of pyoderma gangrenosum in this patient.