What is a migraine?
In general, a migraine is a type of headache. However, the term migraine also includes a number of broader symptoms that occur elsewhere in the body, either before or at the same time as the headache.
- A moderate to severe throbbing headache, lasting from several hours to a few days.
- The headache may be preceded by an aura (see below).
- The pain is typically centred over one eye or temple, or the back of the head, but it may involve both sides of the head.
- Nausea and sensitivity to light and noise often accompany the headache.
- Generally, the migraine prevents you taking part in your usual activities, whether work or pleasure.
A migraine may be preceded by a group of symptoms related to your nervous system, for example, visual changes (e.g. seeing white spots or zig-zag lines in your field of vision), dizziness, feeling pins and needles or, less often, ringing in your ears. Rarely, other symptoms such as speech problems, and even weakness may occur. This group of symptoms is called an aura, and divides migraines into 2 groups: migraine with aura and migraine without aura. Most people who get migraines do not have an aura before the headache.
Who gets migraine?
Migraines tend to run in families. They can occur during childhood, affecting boys and girls equally. After puberty and in adults, migraines are 2-3 times more common in women than in men, and female hormones are thought to play a role in triggering migraines. For example, many women get migraines around the time of their period or at ovulation, when their hormone levels are fluctuating.
Up to 15 per cent of adults get migraines.
What causes migraine?
The well-known trigger factors for migraine, such as a lack of sleep or certain foods, don’t actually cause the migraine on their own, but they do aggravate it. Some experts now believe that the cause of migraine in susceptible people is a chemical signal that triggers pain sensors along the trigeminal nerve, a nerve which supplies the tissues of the cheeks, jaw and forehead. This chemical signal causes:
- inflammation of blood vessels in the head; and
- widening of blood vessels in the head.
This process irritates local nerve fibres, and sends pain signals back to the brain. It is also thought that the brain chemical serotonin plays a role in this process.
There are many well-known trigger factors for migraine including lack of sleep, stress and certain foods. Although migraine trigger factors don’t actually cause a migraine on their own, they can set off the processes that lead to a migraine developing in people who are prone to them.
A person may have several different migraine triggers. Keeping a symptom diary can be helpful for working out the possible triggers for your migraines.
Exposure to more than one trigger can produce an additive effect that is more likely to result in a migraine. For example, in women who tend to get migraines when they get their period, exposure to other triggers around this time, such as late nights and alcohol, may make a migraine more likely. At other times, alcohol on its own may not result in a migraine for this person.
It can be difficult to avoid all of your triggers, all of the time. However, an awareness of your triggers can allow you to avoid some of them, and help you manage and sometimes prevent a migraine.
|Common migraine triggers|
Stress ‘let-down’, e.g. on a weekend or holiday
Missing a meal
Lack of sleep
Long travel journeys
Overexertion when you are unfit
|Physiological||Hormone fluctuations, e.g. menstruation, menopause|
|Environmental||Certain odours, e.g. smoke or smog|
|Medications||Some medications including birth control pills, hormone replacement therapy and some angina medications|
|Alcohol||Especially red wines|
|Foods||Cured meats containing nitrates|
Monosodium glutamate (MSG)
Yoghurt and sour cream
When to see your doctor
If you get headaches that are not helped by usual over-the-counter pain medicines, see your doctor, who can prescribe medicines that may help.
2. Migraine [revised January 2007]. In: eTG complete [Internet]. Melbourne: Therapeutic Guidelines Limited; 2009 Nov. (Accessed 2010 Jan 19.)
3. National Institute of Neurological Disorders and Stroke (NINDS). NINDS Migraine information page (updated 2009, Dec 21). Available at: http://www.ninds.nih.gov/disorders/migraine/migraine.htm (Accessed 2010, Jan 21)