Hemicrania continua changed to chronic paroxysmal hemicrania after treatment with cyclooxygenase-2 inhibitor.

Remission of hemicrania continua (HC) and transformation from HC to chronic paroxysmal hemicrania (CPH) are unusual. We report a patient with left-sided HC who, after a period of remission, presented as CPH. The continuous HC headache disappeared completely after initiating treatment with cyclooxygenase (COX)-2 inhibitor, but reappeared on the same side after 14 months remission with paroxysmal, frequent, intense and short-lasting headache attacks accompanied by ipsilateral cranial autonomic symptoms. This happened shortly after the treatment was discontinued because of withdrawal of the COX-2 inhibitor from the market. The response to indomethacin was prompt, and the patient became completely free from her paroxysmal headache with a dose of 50 mg 2 times daily. This case questions a possible modification effect on the course of HC by use of COX-2 inhibitor, as well as further supporting that some aspects of the pathophysiology of HC may resemble those of CPH, and may argue for common biological mechanisms in HC and CPH.