Chronic migraine: nosographic and epidemiological issues

Excerpt

The term “chronic migraine” (CM) was officially introduced in 2004 in the second edition of the International Classification of Headache Disorders (ICHD-2), which included it in the chapter on migraine at the three-digit level (code 1.5.1) among the complications of the disorder[1]. The latest edition of the classification (ICHD-3 beta version) published in 2013 still uses the term in the chapter on migraine but moves it to the two-digit level (code 1.3), after migraine without aura (1.1) and migraine with aura (1.2)[2]. According to the ICHD-3, a diagnosis of CM must be made when a patient who has been suffering from migraine for some time has had “headache occurring on 15 or more days per month for more than 3 months, which has the features of migraine headache on at least 8 days per month”. …