There are two different kinds of migraine headaches
Classic migraines start with a warning sign, called an aura. The aura often involves changes in the way you see. You may see flashing lights and colors. You may temporarily lose some of your vision, such as your side vision.
You may also feel a strange prickly or burning sensation, or have muscle weakness on one side of your body. You may have trouble communicating. You may also feel depressed, irritable and restless.
Auras last about 15 to 30 minutes. Auras may occur before or after your head pain, and sometimes the pain and aura overlap, or the pain never occurs. The head pain of classic migraines may occur on one side of your head or on both sides.
Common migraines don't start with an aura. Common migraines may start more slowly than classic migraines, last longer and interfere more with daily activities. The pain of common migraines may be on only one side of your head.
Migraine headaches seem to be caused in part by changes in the level of a body chemical called serotonin. Serotonin plays many roles in the body, and it can have an effect on the blood vessels. When serotonin levels are high, blood vessels constrict (shrink). When serotonin levels fall, the blood vessels dilate (swell). This swelling can cause pain or other problems.
Many things can affect the level of serotonin in your body, including your level of blood sugar, certain foods and changes in your estrogen level if you're a woman.
Although much about headaches still isn't understood, some researchers think migraines may be caused by functional changes in the trigeminal nerve system, a major pain pathway in your nervous system, and by imbalances in brain chemicals, including serotonin, which plays a regulatory role for pain messages going through this pathway.
During a headache, serotonin levels drop. Researchers believe this causes the trigeminal nerve to release substances called neuropeptides, which travel to your brain's outer covering (meninges). There they cause blood vessels to become dilated and inflamed. The result is headache pain.
Migraine triggers
Whatever the exact mechanism of headaches, a number of things may trigger them. Common migraine triggers include:
- Hormonal changes. Although the exact relationship between hormones and headaches isn't clear, fluctuations in estrogen seem to trigger headaches in many women with known migraines. Women with a history of migraines often report headaches immediately before or during their periods, and this corresponds to a major drop in estrogen. Others have an increased tendency to develop migraines during pregnancy or menopause. Hormonal medications, such as contraceptives and hormone replacement therapy, also may worsen migraines.
- Foods. Certain foods appear to trigger headaches in some people. Common offenders include alcohol, especially beer and red wine; aged cheeses; chocolate; fermented, pickled or marinated foods; aspartame; overuse of caffeine; monosodium glutamate — a key ingredient in some Asian foods; certain seasonings; and many canned and processed foods. Skipping meals or fasting also can trigger migraines.
- Stress. A hard week at work followed by relaxation may lead to a weekend migraine. Stress at work or home also can instigate migraines.
- Sensory stimuli. Bright lights and sun glare can produce head pain. So can unusual smells — including pleasant scents, such as perfume and flowers, and unpleasant odors, such as paint thinner and secondhand smoke.
- Changes in wake-sleep pattern. Either missing sleep or getting too much sleep may serve as a trigger for migraine attacks in some individuals.
- Physical factors. Intense physical exertion, including sexual activity, may provoke migraines.
- Changes in the environment. A change of weather, season, altitude level, barometric pressure or time zone can prompt a migraine.
- Medications. Certain medications can aggravate migraines.
