Causes of migraine

Migraine is not a disorder of the mind, but rather is related to changes in blood vessels throughout the brain. The exact mechanisms that cause migraines are not known and, indeed, may be numerous.

• One theory is that a trigger or combination of triggers causes the blood vessels in the brain to get larger (dilate); this is accompanied by swelling (inflammation) of the tissue surrounding the brain, and this causes migraine pain.

A number of factors have been shown to start a migraine attack. These are known as ‘trigger factors’. The following are some of the more common trigger factors for migraine, although not all of them will necessarily apply to all sufferers.

• Alcohol, e.g. red wine and beer
• Environmental factors, such as changes in the weather, altitude or time zones
• Specific foods/drinks:
  • foods containing monosodium glutamate
  • certain cheeses and dairy products
  • fermented and pickled foods
  • citrus fruits (e.g. oranges, grapefruit and lemons)
  • bananas
  • figs and raisins
  • processed meats (e.g. deli sandwich meats, hotdogs)
  • saccharin or aspartame 
  • yeast-containing products (e.g. bread and doughnuts)
  • nuts and peanuts
• Stress
• Strong smells (e.g. perfumes) and fumes, tobacco smoke
• Bright or flashing lights
• Too much or too little sleep
• Hunger or fasting
• Excessive activity, especially if you are not fit.

Many women notice that their migraine attacks get worse during their monthly menstrual period. Birth control pills and other forms of oestrogen therapy may make the attack worse. In fact, oestrogen appears to be an important migraine trigger in women as the frequency and nature of migraine attacks can change during puberty, pregnancy and menopause.

Certain medicines have been shown to make the migraine attack worse. These include antibiotics (e.g. tetracycline), medications for acid-related disorders (e.g. cimetidine), medications for the management of angina (e.g. nifedipine and nitroglycerin), and some pain medicines. If you are taking any medicines, you should check with your healthcare provider whether they could be affecting your migraine. Do not stop taking any medicine without first discussing it with your doctor.

Migraine may be hereditary. If one parent suffers from migraine, there is a 40% (four out of every ten) chance that their children will suffer from migraine. If both parents suffer from migraine, the risk increases to 75% (just over 7 out of every 10).