Primary headache diagnosis among chronic daily headache patients.

Chronic daily headache (CDH) refers to a group of non-paroxysmal daily or near-daily headaches with peculiar characteristics that are highly prevalent in populations of neurological clinics and not uncommon among non-patient populations. Most of the patients with CDH had, as primary diagnosis, episodic migraine, which, with the time, presented a progressive frequency, pattern modification and loss of specific migraine characteristics. Other CDH patients had chronic tension-type headache, new daily persistent headache and hemicrania continua, which evolved thru the time to the daily or near-daily presentation. The objective of this study was to determine the primary headache diagnosis among a population of chronic daily headache patients attending a tertiary center for headache treatment. During a 5-year period 651 consecutive chronic daily headache patients attending a private subspecialty center were studied prospectively. The criteria adopted were those proposed by Silberstein et al (1994, revised 1996). Five hundred seventy four patients (88.1%) had episodic migraine as primary headache before turning into daily presentation, 52 (8%) had chronic tension-type headache, 14 (2.2%) had hemicrania continua and 11 patients (1.7%) had new daily persistent headache. CDH is quite frequent in patients from clinic-based studies suggesting a high degree of disability. Emphasis on education of patients suffering from frequent primary headaches with regard to measures that are able to decrease suffering and disability as well as better medical education directed to more efficient ways to handle these patients are necessary to improve outcome of such a prevalent condition.