Hemicrania continua: diagnostic criteria and nosologic status.

Proposals for the diagnostic criteria for hemicrania continua (HC) and also for the nosological status of HC are set forth. The clinical constellation of symptoms and signs making up HC consists of: unilaterality without side shift; absolute indomethacin effect; and long-lasting repetitive attacks of varying duration, eventually with a chronic pattern, the pain being mild to severe. For the typical clinical picture of HC, including a positive 'indotest', we propose the term hemicrania continua vera. More or less analogous, but 'indotest-negative' clinical pictures have provisionally been termed hemicrania generis incerti (of undetermined nature). At the present level of knowledge, the diagnosis of hemicrania generis incerti should be made mostly by exclusion. HC may possibly best be classified along with chronic paroxysmal hemicrania (CPH) as this is the only other headache absolutely responsive to indomethacin. The bond between these two headaches on the one hand and cluster headache on the other should, at most, be a loose one. Interrelationships of these four classifiable headaches are briefly discussed.