Definition and Prevalence
Chronic daily headache is diagnosed based on the presence of headaches occurring for 15 or more days per month, over a period of three consecutive months, without any underlying organic pathology. These headaches last for more than 4 hours per day. This disorder predominantly affects adolescents and adults but can also occur before puberty. It affects up to 4% of young women and up to 2% of young men, with similar prevalence rates reported in studies from Asia, Europe, and the United States (Kavuk et al., 2003).
Classification
Silberstein et al. (1996) defined four categories of chronic daily headache based on symptoms:
- Transformed or chronic migraine
- Chronic tension-type headache
- New daily persistent headache
- Hemicrania continua
Many adolescents with chronic daily headache have a history of episodic migraine, which may transform into chronic migraine gradually over weeks to months or abruptly within hours (Mack, 2004). Approximately a quarter of adolescents with chronic daily headache have no significant past headache history, with new daily persistent headache often triggered by an infection like mononucleosis or a minor head injury (Mack, 2004).
Symptomatology
Patients with chronic daily headache typically experience at least two types of headaches:
- Severe Intermittent Headaches: These are migrainelike, often described as throbbing, severe, crushing, knife-like, or hatchet-like, and are usually pancephalic or frontal in location. Associated symptoms include nausea, photophobia, phonophobia, and osmophobia. Sleep may help alleviate pain, but headaches often persist upon awakening. These severe headaches occur multiple times a week.
- Continuous Headache: Present 24/7, this headache waxes and wanes in severity, often worsening in the morning or at the end of the school day. The pain is similar to that of severe headaches but less intense, and may also have features of a tension-type headache, described as band-like or crushing.