What causes a migraine?
Migraines are thought to be caused by a change in blood vessels to the brain. It may also start like other headaches, with a wave of electrical activity spreading across the brain. This electrical activity is thought to give rise to auras such as tingling in face and hands and sensitivity to smell. The electrical activity also stimulates the nerves that supply sensation to the head and neck, known as the trigeminal nerve, causing localised pain. In addition, such activity heightens the sensitivity of nerve cells elsewhere in the brain, causing symptoms such as nausea and vomiting, light and sound sensitivity and pulsing sensation. The different emotional, diet-related and environmental triggers that can start a migraine include: tension and stress; tiredness, physical exhaustion, lack of sleep or oversleeping; certain foods (e.g., cheese, chocolate, citrus fruits, tomatoes), food additives (e.g., monosodium glutamate (MSG) and sodium nitrite), certain drinks (e.g., caffeine and wine); hormonal changes (e.g., before or during menstruation, during pregnancy or menopause); head trauma (e.g., sporting injury); bright or flickering lights, excessive noise, strong perfume; dehydration, and; medication (e.g., oral contraceptive pill, vasodilators).