[Coexistance of cluster headache and hemicrania continua: a case report].

We reported a 36-year-old man, who suffered from cluster headache (CH) associated with hemicrania continua (HC). The continuous, dull or pressure-type headache appeared on the same side of the CH during the third month of a prolonged cluster period, and fluctuated in the severity of pain. This headache was aggravated when the CH was ameliorated by the administration of lithium carbonate. This converse relationship between CH and HC persisted during an on-off trial of the lithium carbonate, and the HC was exacerbated again after the complete cessation of CH. Retrobulbar pain and nasal congestion were present as components of HC similarly to CH, but they subsided gradually and the pressure-type vascular headache over the temporal area predominated later. The continuous headache lasted more than 3 months, and responded significantly to the indomethacin at a dose of 75mg/d. The clinical course of this patient suggests that HC and CH have a common pathomechanism including hyperactivation of the trigemino-vascular reflex, and may be different in the involvement of other central pathway of pain generation. Indomethacin may deserve consideration for the treatment of continuous headache that appears during an atypical course of other primary headaches.