Report of eight new cases of hypnic headache and mini-review of the literature.

Hypnic headache is a rare condition first described by Raskin in 1988. This headache is not included in the first edition of the International Headache Society classification (IHC 1st Edition). We describe eight new Italian hypnic headache cases and consider our findings in the light of literature data. Our cases do not completely fulfil the diagnostic criteria for the syndrome proposed in 1997 by Goadsby and Lipton: four of our patients reported an attack duration longer than 60 minutes (ranging from 3 to 10 hours) and five reported unilateral pain. These data are in line with an analysis of all 61 cases published in the literature to date, which reveals a pain duration of over 60 minutes in 45.9% of the cases and unilateral attacks in 36%. Hypnic headache will be included in the fourth chapter (Other Primary Headaches) of the revised edition of the above-mentioned classification (IHC 2nd Edition).