Takayasu's arteritis in a patient with Crohn's disease: an unexpected association during infliximab therapy.

We report a 20-year-old woman with Crohn's disease (CD) who developed anterior neck pain while being treated with the anti-tumor necrosis factor (TNF)-alpha monoclonal antibody, infliximab. She showed no symptoms suggestive of active CD except for tenderness along the left common carotid artery with marked increases in serum TNF-alpha and inflammatory reactions. Based on thickened walls of large vessels with enhancement effects on computed tomography, she was diagnosed as having associated Takayasu's arteritis (TA), which was successfully treated with corticosteroid. Even if CD is controlled by infliximab, other autoimmune disorders, such as TA, may develop as a complication.