Analgesic rebound as a cause of hemicrania continua.

Hemicrania continua is a rare unilateral headache of unknown etiology that characteristically responds to indomethacin. Most previous case reports fail to mention analgesic use by these patients or the results of analgesic avoidance. This is a case report of a 42-year-old woman with persistent unilateral headaches that ceased 3 weeks after administration of analgesics was stopped. Thus, hemicrania continua can be caused by analgesic rebound.