Description of series of 10 patients with hypnic headache: Discussion of the diagnostic criteria.

INTRODUCTION: Hypnic headache is a rare primary headache. The diagnostic criteria of the International Headache Classification (IHS) for this condition are discussed, as they have been modified in the new edition of the 2013. PATIENTS AND METHODS: The clinical characteristics, and fulfilment of the criteria of the IHS classification in a series of 10patients diagnosed in our Headaches Clinic, are analyzed. RESULTS: The mean age of onset of symptoms was 52.1years (SD: 13.4; range: 28-69). The pain was reported as oppressive in 60% of the patients, and as sharp in 30%. The headache was described as holocranial in 60% and hemicranial in 40%. They occurred exclusively during night-time sleep in 80% of the patients. The mean duration of headache was 136.5minutes (range: 10-480). The mean number of days per month was 16.4 (range: 3-30), and 50% had less than 15 headache days per month. No patient had autonomic manifestations, 70% had phonophobia, 50% had photophobia, and 50% had both. All of them (100%) had a VAS score equal to or higher than 8. CONCLUSIONS: The criteria for hypnic headache of the new classification are best suited to the characteristics of these patients. Our results show the major changes in the criteria: pain is not always dull, headache frequency may be less than 15days a month, and it can occur in people under age 50. There may be phonophobia or photophobia only, or both. Although it does not form part of the diagnostic criteria, the pain intensity in our series was higher than described.