Collecting the History in the CDH Patients

Chronic daily headache (CDH) is a frequently used but nonspecific term that includes all the headaches which are experienced on more than 15 days per month for at least 3 months. There are numerous headache disorders, both primary and secondary, that behave like this. They represent a great challenge to medical professionals and a burden to the patient and society. The primary CDHs (for which no underlying cause is found) are the most common. Of those, chronic migraine is the leading problem encountered in specialized headache clinics, much more common than other primary CDHs of long duration (≥4 h/day). Most important primary CDHs of short duration (<4 h/day) are the trigeminal autonomic cephalalgias (TACs), i.e., chronic cluster headache. There is a host of secondary causes of CDH, and they need to be carefully diagnosed based on history, examination, and additional investigations.