Chronic daily headache (CDH) is not a formal diagnosis in the International Classification of Headache Disorders, 3rd edition (ICHD-3). Rather, it is an umbrella term used to describe a range of primary and secondary headache disorders characterized by duration and/or frequency depending on the specific headache type. For example, some long CDH subtypes (see below) must persist for 15 or more days per month for at least 3 months while shorter duration CDH subtypes- e.g., cluster or paroxysmal hemicrania- must persist for at least one year without remission or with remissions lasting less than three months.
So while not a distinct diagnosis itself, chronic daily headache encompasses a group of headache disorders marked by extremely frequent headache attacks.
- CDH has an estimated worldwide prevalence of around 4% in adults. It is 2-3 times more common in females.
- The most common headache types underlying CDH are chronic tension-type headache and chronic migraine. CDH results in substantial disability and economic costs.
The main CDH subtypes of long duration (≥4 hours per headache) are:
- Chronic migraine: evolution from episodic migraines, migraine features on ≥ 8 days/month
- Chronic tension-type headache: pressing, bilateral pain without migraine features
- Medication overuse/adaptation headache: worsening headaches due to overuse of acute medications
- Hemicrania continua: unilateral, moderate pain with cranial autonomic symptoms
- New daily persistent headache: daily headaches without characteristic features
Other shorter duration headaches (<4 hours per headache) can also be chronic, like:
- Chronic cluster headache
- Chronic paroxysmal hemicrania
- Short-lasting unilateral neuralgiform headache attacks
- Hypnic headache
- Primary stabbing headache
CDH diagnosis depends on meeting criteria for specific headache types after excluding secondary causes.
- Most patients have an unrevealing history and normal neurological exam.
- Further diagnostic testing is based on the presence of "red flags" like:
- Differential includes secondary headaches from infections, mass lesions, vascular disorders, etc. See link above for more information.
Treatment focuses on the specific CDH diagnosis and preventing medication overuse/adaptation headache.
- Chronic migraine: preventives, avoidance of triggers, acute medications, assess for medication overuse/adaptation headache.
- Chronic tension-type headache: preventives, behavioral and physical therapy
- Medication overuse/adaptation headache: Establish preventives
- Other CDH subtypes have more specific treatments e.g. indomethacin for hemicrania continua