Chronic migraine is a neurological disorder defined by 15 or more headache days per month for at least three months, with at least eight days meeting criteria for migraine (or responding to migraine-specific medication before all features fully develop).
A migraine-type headache typically has two or more of the following characteristics:
- One-sided location
- Pulsating or throbbing quality
- Moderate to severe intensity
- Worsening with routine physical activity
Migraines are usually accompanied by nausea and/or vomiting, or sensitivity to light and sound.
Unlike episodic migraine, chronic migraine can dominate most of the month—significantly affecting work, family life, sleep, and mood. Accurate diagnosis also includes evaluating for contributing factors such as medication-overuse headache, sleep disorders, hormonal cycles, stress, dehydration, missed meals, weather changes, and prolonged screen strain.
For prevention, one evidence-based option is onabotulinumtoxinA (BOTOX®), administered on a fixed schedule to reduce headache frequency, severity, and disability.