Chronic: marked by long duration, by frequent recurrence over a long time, and often by slowly progressing seriousness; not acute. By International Headache Society criteria, Migraines and other headache disorders are termed chronic when they occur 15 or more days per month.
Migraines and many headache disorders can be chronic or episodic.
You can read more about both chronic and episodic forms of Migraines and Headaches in our section on:
For more terms, see our Migraine and Headache Glossary.
Medical review by John Claude Krusz, PhD, MD.