Definition of Migraine:

A migraine is a common type of headache that may occur with symptoms such as nausea, vomiting, or sensitivity to light. In many people, a throbbing pain is felt only on one side of the head.

Some people who get migraines have warning symptoms, called an aura, before the actual headache begins. An aura is a group of symptoms, usually vision disturbances, that serve as a warning sign that a bad headache is coming. Most people, however, do not have such warning signs.

See also:

• Headache
• Mixed tension migraine (features of both a migraine and tension headache)

Causes, incidence, and risk factors:

A lot of people get migraines -- about 11 out of 100. The headaches tend to first appear between the ages of 10 and 46. Occasionally, migraines may occur later in life in a person with no history of such headaches. Migraines occur more often in women than men, and may run in families. Women may have fewer migraines when they are pregnant. Most women with such headaches have fewer attacks during the last two trimesters of pregnancy.

A migraine is caused by abnormal brain activity, which is triggered by stress, certain foods, environmental factors, or something else. However, the exact chain of events remains unclear.

Scientists used to believe that migraines were due to changes in blood vessels within the brain. Today, most medical experts believe the attack actually begins in the brain itself, where it involves various nerve pathways and chemicals. The changes affect blood flow in the brain and surrounding tissues.

Migraine attacks may be triggered by:

• Alcohol
• Allergic reactions
• Bright lights
• Certain odors or perfumes
• Changes in hormone levels (which can occur during a woman's menstrual cycle or with the use of birth control pills)
• Changes in sleep patterns
• Exercise
• Loud noises
• Missed meals
• Physical or emotional stress
• Smoking or exposure to smoke

Certain foods and preservatives in foods may trigger migraines in some people. Food-related triggers may include:

• Any processed, fermented, pickled, or marinated foods
• Baked goods
• Chocolate
• Dairy products
• Foods containing monosodium glutamate (MSG)
• Foods containing tyramine, which includes red wine, aged cheese, smoked fish, chicken livers, figs, and certain beans
• Fruits (avocado, banana, citrus fruit)
• Meats containing nitrates (bacon, hot dogs, salami, cured meats)
• Nuts
• Onions
• Peanut butter

This list may not be all-inclusive.

True migraine headaches are not a result of a brain tumor or other serious medical problem. However, only an experienced health care provider can determine whether your symptoms are due to a migraine or another condition.