This type of migraine usually peaks in one hour and last several hours. The precipitating events for migraine headaches are different for each patient. Some migraines are precipitated by stress, excitement, bright lights, menstruation, alcohol, certain foods, fatigue, irregular sleep, or missed meals. For other patients, there is no known precipitating event. The exact etiology of migraine headaches is not known.
Evidence suggests that neuralgic, vascular, and chemical factor are involved.
The prodromal phase is associated with vasoconstriction and decreased blood flow. The headache phase is associated with vasodilatation and increased blood flow. This stretching of the blood vessels causes pain. Serotonin is thought to play an important role in migraines. It constricts blood vessels, which stimulates pain receptors.