The trigeminal nerve pathway carries nerve signals from the head and face to the brain. When a migraine is triggered, the trigeminal nerve releases neuropeptides causing inflammation and dilation of the blood vessels. Subsequently, trigeminal nerve endings stimulate the release of more neuropeptides and a vicious cycle is begun. Serotonin regulates pain messages via the trigeminal pathway. Three out of four migraineurs are women and migraine is considered a hereditary disease.
Migraines are generally of two types, known as classic and common.
Typically, migraines are biased to one side of the head and often the pain is localized. Common migraine is considered any migraine not preceded by an aura or other symptomatic warning to the patient. Migraines often start in the teen years but are more likely to occur for the first time between 20 and 40 years of age. Frequency may be one a year or as often as once a week. Medications such as birth control pills, certain blood pressure medications, certain antidepressants, and hormone replacement therapy can cause migraine by their use, or by starting or stopping their use.