What Causes A Migraine?

What Causes a Migraine

A migraine is a type of headache that causes throbbing pain, usually on one side of the head. Typically, the migraine pain is accompanied by other symptoms such as nausea, vomiting, sensitivity to light, or sensitivity to sound. The causes of migraine are not fully understood, but we know that genetics and environmental factors play a role.


The current theory is that migraine is a disorder of nerves and blood vessels in the brain. Specifically, a migraine results from changes in brainstem activity and its connectivity with the trigeminal nerve, the main pain pathway involved in migraine, which affects nerve signals, chemicals (such as serotonin) and blood vessels in the brain and surrounding tissues. These changes may explain why migraines occur. The abnormal brain activity can be triggered by many things, often by incoming information which would not bother most people. This results in an exaggerated electrical and chemical response of the brain which causes a change in blood flow by narrowing the blood vessels, which in turn affects the nerves in the brain, causing pain.

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Migraine Triggers

Some factors may cause a migraine attack – these are called triggers. Migraine triggers can be internal such as sleep patterns, stress, and hormonal changes or external such as changes in weather, exposure to bright lights or consuming certain foods and drinks. No one trigger is common for everyone and a known trigger does not always trigger a migraine attack. It may help to keep a diary to track the foods you eat, your sleep patterns, weather conditions, and physical activity as well as the day and time you experience a migraine attack. Once you find what triggers may cause your migraines, try to avoid them, or learn how to manage your triggers.  

Some common triggers include:  

Hormonal changes in women. Women may experience migraine attacks related to changes in estrogen levels which cause fluctuations in serotonin levels. Migraines often increase after puberty and decrease after menopause.  

Food and drinks. Certain foods and drinks, such as aged cheese, alcoholic beverages (especially red wine), and caffeine (such as coffee and chocolate) may be responsible for triggering a migraine attack. Skipping meals and dehydration may also be triggers, since your blood sugar levels could drop if you miss a meal.

Stress. Feeling overwhelmed at work or home, anxiety, worry, and fear may trigger migraines. Your body can also be stressed if you exercise too much or do not get enough sleep. During stressful events, certain chemicals in the brain are released to cope with the situation (known as the “flight or fight” response). The release of these chemicals can trigger a migraine. Interestingly, some people report that their migraine attacks start when the stress reduces. Sometimes, this is experienced as “weekend headaches” – after a stressful week at work, migraines may be experienced during the weekend when you are more relaxed.

Sensory stimuli. Bright lights or flashing lights and loud sounds can induce a migraine attack. Some odors, usually strong ones, may trigger a migraine attack or worsen an attack that has already started. Sensitivity to sensory stimuli are common symptoms of migraine; sensitivity to light and sound are included in the criteria used to diagnose migraine. So, it is unclear if light and sound are themselves triggers, or if heightened sensitivity to them are early features in the attack, representing warning signs, but in any case, try avoiding these stimuli.

Sleep changes. Missing sleep or getting too much sleep can trigger migraines in some people. It makes sense that when your sleep schedule becomes irregular, you would be more prone to migraine, as sleep is important for normal body functions, including the brain.

Weather changes. Change in weather or barometric pressure are known to trigger migraine attacks. High humidity and heat can easily lead to dehydration, another common trigger. The weather cannot be controlled, so it is important to be aware of current and upcoming changes in weather. If you know that the current conditions are not good for your migraine, try staying inside and adjust your schedule accordingly.

Medications. Ironically, taking migraine acute medications  prescribed by your healthcare provider more than 10 days per month, may cause more migraine attacks, a phenomenon known as medication overuse headache (MOH). Limiting use of medication or using drug-free treatments may reduce the risk for developing medication overuse headache.

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Risk Factors

Some things make some people more likely than others to get migraines – these are called risk factors.

These factors include:

Family history. Migraine is known to run in families. More than 70% of people with migraine have a family history of migraine. If both parents have migraine there is a 90% chance you will also have migraine. Over half of migraine patients have a first-degree relative also affected by a similar condition.

Gender. Women are three times more likely than men to have migraines. This is explained by hormonal fluctuation of estrogen, which occur around the time of the period, during pregnancy or when going through menopause, and have been related to the contraction of blood vessels.

Age. Migraines can start at any age, though most people have their first migraine attack during adolescence. Migraine is most prevalent between the ages of 25 to 55 and generally decline after 55.

Hormonal changes. In woman, migraines typically begin around the onset of their period. Changes in severity and frequency may occur during pregnancy or menopause (generally, migraines improve after menopause).

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Resources

Dodick DW.A phase‐by‐phase review of migraine pathophysiology. Headache: The Journal of Head and Face Pain. 2018;58:4-16.

Rothrock J. The truth about triggers. Headache: The Journal of Head and Face Pain. 2008;48(3):499-500.

Pavlovic JM, Buse DC, Sollars M, et al. Trigger factors and premonitory features of migraine attacks: summary of studies. Headache: The Journal of Head and Face Pain. 2014;54(10):1670-1679.

Lipton. RB, BigalME.  Migraine: epidemiology, impact, and risk factors for progression. Headache: The Journal of Head and Face Pain  2005;45:S3-S13.

Anttila V, Wessman M, Kallela M, Palotie A. Genetics of migraine. In:Geschwind DH, Paulson HL, Klein C. eds. Handbook of Clinical Neurology. 3rd ed. Amsterdam, Netherlands: Elsevier; 2018:493-503.

Puledda F, Messina R, Goadsby PJ. An update on migraine: current understanding and future Directions. J Neurol. 2017;264:2031-2039.

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