Table 3 Diagnostic criteria for chronic migraine by the ICHD-2 (2004) and by the ICHD-2R (2006)

ICHD-2 (2004)

 A. Headache fulfilling criteria C and D for migraine without aura on ≥15 days per month for >3 months

 B. Not attributed to another disorder

ICHD-2R (2006)

 A. Headache (tension-type and/or migraine) on ≥15 days per month for ≥3 months

 B. Occurring in a patient who has had at least five attacks fulfilling criteria for 1.1 Migraine without aura

 C. On ≥8 days per month for ≥3 months headache has fulfilled C.1 and/or C.2 below; that is, has fulfilled criteria for pain and associated symptoms of migraine without aura:

  1. Has at least two of a–d:

    a. Unilateral location

    b. Pulsating quality

    c. Moderate or severe pain intensity

    d. Aggravation by or causing avoidance of routine physical activity (e.g., walking or climbing stairs)

  And at least one of a or b below:

    a. Nausea and/or vomiting

    b. Photophobia and phonophobia

  2. Treated and relieved by triptan(s) or ergot before the expected development of C.1 above

 D. No medication overuse and not attributed to another causative disorder