Secondary "hypnic headache".

Hypnic headache is a rare form of primary headache with attacks occurring exclusively with sleep. As it is typical of the elderly, a wide range of alternative diagnosis must be considered. We present a case report of a 54-year-old woman with unsuspected secondary hypnic headache that was relieved by anti-hypertensive therapy. We reviewed the literature to evaluate the usual diagnostic workup performed in hypnic headache patients. We suggest that 24 h ambulatory blood pressure monitoring may be included in the evaluation of nocturnal headache complaints especially in the elderly, in whom essential hypertension is a very frequent comorbidity.