early 15c., from Middle French lesion, from Latin laesionem (nominative laesio) injury, from past participle stem of laedere to strike, hurt, damage, of unknown origin. Originally with reference to any sort of hurt, whether physical or not.
Most migraines last about 4 hours, but severe ones can last up to a week. How often they happen differs for everyone, but itâs common to get two to four headaches per month. Some people may get migraines every few days, while others get them once or twice a year.
Episodic cluster headaches are defined as those that occur in periods (clusters) lasting from 7 days to 1 year. Clusters are separated by headache-free intervals lasting at least 2 weeks. Clusters usually last 2 weeks to 3 months. Chronic cluster headaches are defined as those that occur for more than 1 year without remission (intervals in which headaches do not occur) or with remissions lasting less than 2 weeks.