A migraine headache is typically a pulsating or throbbing pain that ranges from moderate to severe. It can affect one or both sides of the head. It is worsened by physical activity, light, sounds, or odors and is accompanied by nausea, vomiting, and sensitivity to sounds, light, and/or odors.
Although migraines can start at any age, they usually begin during puberty or young adulthood. In most people, migraines recur periodically (fewer than 15 days a month). After age 50, headaches usually become significantly less severe or resolve entirely. Migraines are 3 times more common among women. In the United States, about 18% of women and 6% of men have a migraine at some time each year.
Migraines may become chronic. That is, they occur 15 or more days a month. Chronic migraines often develop in people who overuse drugs to treat migraines.
Migraines tend to run in families. More than half the people who have migraines have close relatives who also have them.
Migraines occur in people whose nervous system is more sensitive than that of other people. In these people, nerve cells in the brain are easily stimulated, producing electrical activity. As electrical activity spreads over the brain, various functions, such as vision, sensation, balance, muscle coordination, and speech are temporarily disturbed. These disturbances cause the symptoms that occur before the headache (called the aura). The headache occurs when the 5th cranial (trigeminal) nerve is stimulated. This nerve sends impulses (including pain impulses) from the eyes, scalp, forehead, upper eyelids, mouth, and jaw to the brain. When stimulated, the nerve may release substances that cause painful inflammation in the blood vessels of the brain (cerebral blood vessels) and the layers of tissues that cover the brain (meninges). The inflammation accounts for the throbbing headache, nausea, vomiting, and sensitivity to light and sound.
A rare subtype of migraine called familial hemiplegic migraine is associated with genetic defects on chromosome 1, 2, or 19. The role of genes in the more common forms of migraine is under study.
Estrogen, the main female hormone, appears to trigger migraines, possibly explaining why migraines are more common among women. Migraines can probably be triggered when estrogen levels increase or fluctuate. During puberty (when estrogen levels increase), migraines become much more common among girls than among boys. Some women have migraines just before, during, or just after menstrual periods. Migraines often occur less often and become less severe in the last two trimesters of pregnancy when estrogen levels are relatively stable, and they worsen after childbirth when estrogen levels decrease rapidly. As menopause approaches (when estrogen levels are fluctuating), migraines become particularly difficult to control. Oral contraceptives (which contain estrogen) and estrogen therapy may make migraines worse and may increase the risk of stroke in women who have migraines with an aura.
Other triggers include the following:
Head injuries, neck pain, or a problem with the joint of the jaw (temporomandibular joint disorder) sometimes trigger or worsen migraines.
In a migraine, pulsating or throbbing pain is usually felt on one side of the head, but it may occur on both sides. The pain may be moderate but is often severe and incapacitating. Physical activity, bright light, loud noises, and certain odors may make the headache worse. This increased sensitivity makes many people retreat to a dark, quiet room, lie down, and sleep if possible. Migraines often subside during sleep. The headache is frequently accompanied by nausea, sometimes with vomiting and sensitivity to light, sounds, and/or odors. Severe attacks can be incapacitating, disrupting daily routines and work.
People often have sensations warning them that an attack is about to begin. These sensations, called the prodrome, may include mood changes, loss of appetite, and nausea.
In about 25% of people, migraines are preceded by an aura. The aura involves temporary, reversible disturbances in vision, sensation, balance, muscle coordination, or speech. People may see jagged, shimmering, or flashing lights or develop a blind spot with flickering edges. Less commonly, people experience tingling sensations, loss of balance, weakness in an arm or a leg, or difficulty talking. The aura lasts minutes to an hour before and may continue after the headache begins. Some people experience an aura but have only a mild or no headache. These mild headaches may be similar to tension-type headaches.
Migraine attacks may last for hours to a few days (typically 4 hours to 3 days). Usually, they subside during sleep. They may occur frequently for a long time, then disappear for many weeks, months, or even years.
Doctors diagnose migraines when symptoms are typical and results of a physical examination (which includes a neurologic examination—see Symptoms and Diagnosis of Brain, Spinal Cord, and Nerve Disorders: Physical Examination) are normal.
No procedure can confirm the diagnosis. If headaches have developed recently or if certain warning signs are present (see Headaches: Warning signs), computed tomography (CT) or magnetic resonance imaging (MRI) of the head and sometimes a spinal tap (lumbar puncture) may be done to exclude other disorders. If people who are known to have migraines develop a headache that is similar to their previous migraines, doctors rarely do tests. However, if the headache is different, particularly if warning signs are present, a doctor's examination and often tests are needed.
When treatment does not prevent people from having frequent or incapacitating migraines, taking drugs every day to prevent migraine attacks can help (see Table: Headaches: Drugs Used to Treat Migraines). Taking preventive drugs may help people who are taking other migraine drugs too often and need to reduce their use.
Beta-blockers, such as propranolol, are often used. The anticonvulsants topiramate and divalproex and the tricyclic antidepressant amitriptyline are also effective. The choice of a preventive drug is based on the side effects of the drug and on other disorders present. For example, people who are overweight may be given topiramate, which can promote weight loss. People with depression or insomnia may be given amitriptyline (an antidepressant—see Mood Disorders: Drugs Used to Treat Depression).
Migraines cannot be cured, but they can be controlled.
Doctors encourage people to keep a headache diary. In it, people write down the number and timing of attacks, possible triggers, and their response to treatment. With this information, triggers may be identified and eliminated when possible, and doctors can better plan and adjust treatment. Behavioral interventions (such as relaxation, biofeedback, and stress management) are used to control migraine attacks, especially when stress is a trigger or when people are taking too many drugs to control the migraines.
Some drugs stop a migraine from progressing. Some are taken to control the pain. Others are taken to prevent migraines.
When migraines are or become severe, drugs that can stop (abort) the migraine from progressing are used. They are taken as soon as people sense a migraine is starting. They include the following:
Because triptans and dihydroergotamine may cause blood vessels to narrow (constrict), they are not recommended for people who have angina, coronary artery disease, or uncontrolled high blood pressure. If older people or people with risk factors for coronary artery disease need to take these drugs, they must be monitored closely.
If migraines are usually accompanied by nausea, an antiemetic may also be taken. Antiemetics (such as prochlorperazine), taken alone, may stop mild or moderate migraines from progressing.
For less severe migraines, analgesics with or without caffeine can help control the pain. They can be taken as needed during a migraine, with or instead of a triptan.
Overuse of analgesics, caffeine (in analgesic preparations or in caffeinated beverages), or triptans can lead to daily, more severe migraines. Such headaches, called medication overuse headaches, occur when these drugs are taken more than 2 to 3 days each week. Missing or reducing a dose or taking it late may trigger or worsen a migraine.
When other treatments are ineffective in people with severe migraines, opioids may be needed (see Pain: Treatment of Pain). Opioids are a last resort.
Last full review/revision May 2012 by Stephen D. Silberstein, MD