Abstract
Chronic migraine (CM) is one of the most disabling diseases, and it is commonly misdiagnosed and mistreated. Despite the importance of a timely and accurate diagnosis for the effective management of CM, recent surveys have shown that only 20-25% of individuals with CM receive a correct diagnosis. The obvious consequences of misdiagnosed CM are prolongation of symptoms and their associated effects on disability and health-related quality of life. Additionally, mistreatment of CM can lead to acute medication overuse headache with escalation of headache and end organ damage. Ideally, a diagnosis of CM should be made in the primary care setting, based on a thorough medical history including detailed descriptions of headaches occurring earlier in life as well as current headaches, and the range of headaches (not just the worst headaches). In our experience, it is often equally informative to ask the patient about the number of headache-free days (HFDs) and no accompanying symptoms (i.e., crystal-clear days) to quantify headache days and accurately estimate headache frequency/impact. Headache frequency is important, as this count is one key means of diagnosing CM, which requires ≥ 15 headache days/month, noting that these do not need to be migraine days. A headache day is defined as more than 4 h a day of headache. Comorbidities are common in CM and may affect the treatment choice and increase disability. Every CM patient should be offered a preventive migraine treatment. In this commentary, we provide practical insights and tips for diagnosing CM and cover issues of medication overuse, patient communication, diagnostic testing, and when to make a referral. Our key message to physicians for a patient who comes to the clinic with frequent disabling headaches having features of migraine is to assume CM until proven otherwise.