The actual causes of headaches are unclear and different types of headache have many contributory factors that cause them. Tension headaches can be triggered by stress
or psychological problems such as depression
. Poor posture and deteriorating eyesight cause the scalp and neck muscles to tense leading to tension headaches. Food, strong odours, bright sunlight and the menstrual cycle
can all trigger a tension headache.
Cluster and migraine headaches are termed 'vascular headaches' meaning blood vessels dilate and swell in the tissue surrounding the head causing pain. Cluster headaches are believed to be caused by over activity in the part of the brain called the hypothalamus. This activity can be triggered by drinking alcohol or smelling solvents, petrol and perfumes. Extreme temperatures can also bring on cluster headaches. Migraine headaches are caused by the enlargement of the temporal artery and release of chemicals under the skin of the temple. The chemicals cause pain, inflammation and further enlargement of the temporal artery that magnifies the pain.
Diseases that cause secondary headaches include brain tumours, haematomas (bleeding from ruptured veins or arteries), bacterial meningitis, strokes, high blood pressure
, sinus infections, carbon monoxide poisoning, glaucoma and hypothyroidism.