By Sally Robertson, B.Sc

Reviewed by Dr. Jennifer Logan, MD, MPH

A migraine is a common form of primary headache disorder, experienced as a recurrent throbbing headache of moderate to severe intensity. It is usually one-sided but may affect both sides of the head. Migraine sufferers may experience other symptoms, including nausea; vomiting; sensitivity to light, sounds and smells; and disturbed vision.

Symptoms can be severe enough to interfere with day-to-day life to the extent that people may take time off from work or school. Movement can make symptoms worse, particularly head movements, and sufferers often feel the need to lie still in a dark room.

The condition is inherited and involves an instability in how the brain manages incoming sensory information, which can be influenced by physiological factors such as sleep, exercise, and hunger. It is not clear exactly what causes this change in brain activity, but the change affects nerve signals, blood vessels, and chemicals in the brain.

Estimates suggest that more than 38 million adults in the United States experience migraines, and that 2 to 3 million of them suffer from chronic migraines. Migraines can start at any age, but tend to become less troublesome as a person ages.

Migraine triggers
Many factors have been suggested as migraine triggers, including hormonal, emotional, dietary, physical, medicinal, and environmental factors. The triggers are specific to each individual, and sufferers are advised to keep a diary logging daily life patterns to help identify any common factor.

Hormonal factors
Some women find that migraines develop around the time of their period, possibly due to changes in levels of the hormone estrogen. These migraines tend to occur between two days prior to the period and up to three days after it has ended.

If a woman exclusively experiences migraines around the time of their period, the migraine is referred to as pure menstrual migraine. However, the majority of females who suffer during menstruation have migraines at other times as well, in which case the condition is referred to as menstrual-related migraine.

Women often find that migraine symptoms start to improve following the menopause, although the menopause can also be a trigger or make symptoms worse in some cases.

Emotional factors
One main emotional factor associated with migraines is stress. However, some individuals report that the migraines start once they are relieved of stress. This is sometimes referred to as a “weekend headache,” where the migraine begins once a stressful working week has ended, and a person is feeling more relaxed. Emotions such as tension, shock, anxiety, and excitement can also trigger a migraine.

Physical factors
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Two important examples of physical factors that can trigger a migraine are sleep and posture. The effect of sleeping patterns influences migraine onset in different ways, depending on the individual.

Some people find that too little sleep, staying up late too often, and feeling tired are factors that trigger the headaches. Other migraine sufferers report that the opposite is the case, with sleeping in later than usual or napping over the course of the morning causes the migraine.

A good posture is very important when sitting in the same place for long periods, for example, at a computer during work hours. Poor posture can cause tension in the neck and/or shoulders, which is thought to be involved in migraine onset.

Dietary factors
In around 10% of people who experience migraines, dietary factors trigger the headaches. Missing meals or not eating enough can lead to onset, and people may find that regularly consuming small but nutritious meals helps to relieve the migraine.

Some research suggests that the tyramine in red wine and soft cheeses such as brie may induce a migraine. Some food additives may contribute to migraine onset, with sufferers commonly reporting that nitrates, aspartame and monosodium glutamate seem to be triggers.

Excessive intake of caffeine is thought to be another trigger, although some people report that suddenly cutting caffeine out of their diet can also be a trigger. People who suspect caffeine is a trigger are advised to limit themselves to no more than five caffeine-containing drinks a day and to cut down caffeine intake slowly if they do decide to eliminate it.

Environmental factors
Examples of environmental factors include high altitude, high humidity, bright or flickering lights, and loud noises. It is not yet clear whether light and sound are actually triggers or whether people are highly sensitive to them as a feature of the migraine. Sitting in front of a computer for a long time can worsen migraine, and sufferers are advised to take regular breaks from looking at monitors and to use antiglare screens.

Medicines
Some examples of medicinal triggers are sleeping tablets, hormone replacement therapy, and the combined contraceptive pill.

Avoiding triggers of migraine
One of the best ways to prevent migraines is to avoid any triggers. When a migraine sufferer is keeping a diary to help identify potential triggers or to monitor how well a migraine treatment is working, they should try to ensure they write down the following:

The date the migraine occurred
The time of day it began
The symptoms
Any medication that was taken
When the migraine ended
About one-third of people who have migraines find they experience temporary warning signs, which are referred to as “aura.” People should also make a note of these in their diaries.

Examples of warning signs include:

Vision problems including seeing flashing lights, blind spots or zig-zag patterns
Numbness or tingling sensation, which tends to start in one hand and then move up the arm into the face, lips, and tongue
Feeling off-balance or giddy
Difficulty talking
In rare cases, loss of consciousness
These warning signs usually develop over the course of about five minutes and tend to last for up to one hour. Aura symptoms are not always followed by a severe migraine; sometimes, only a mild headache or no headache at all follows.

Treatment
There is no cure for migraine, but symptoms can be relieved with over-the-counter pain killers such as paracetamol, ibuprofen, and aspirin. It is not advisable to wait until a headache becomes worse before taking the painkiller, because once it has worsened, it is often too late for the medicine to work.

If painkillers are not enough to relieve the migraine, a doctor may prescribe pain killers developed specifically for migraine called triptans, which work by reversing the brain changes that lead to migraine. They contract the blood vessels in the brain, reversing the widening that is thought to be part of the migraine process. They may be injected or taken in the form of tablets or a nasal spray.

Other drugs that can sometimes work are anti-sickness medicines, and these can be taken alongside triptans and painkillers. Again, these should be taken as soon as a migraine begins, before it worsens.

Other approaches include taking a combination medicine that includes pain killers and anti-sickness agents and acupuncture.

Several medications are also available to prevent migraines in people who experience migraines frequently.

Sources
Causes. Migraine. NHS 2019. Available at: https://www.nhs.uk/conditions/migraine/causes/

Migraine. BUPA. Available at: www.bupa.co.uk/health-information/brain-nervous-system/migraine

More than “just a headache.” The Migraine Trust. Available at: www.migrainetrust.org/…/

Migraine Statistics. Migraine.com. Available at: https://migraine.com/migraine-statistics/

Common Triggers. The Migraine Trust. Available at: www.migrainetrust.org/…/