What causes a headache?
Most headaches are caused by tension in muscles, dehydration, lack of sleep, stress, skipped meals or illness. Migraines are a separate condition linked to changes in the brain and nerves.
The brain itself has no pain receptors. Headache pain comes from nerves in the blood vessels, muscles and tissues around the head and neck. Tension-type headaches, the most common kind, often feel like a tight band around the head and are linked to stress, poor posture and muscle strain.
Migraines usually cause throbbing pain on one side of the head, often with nausea and sensitivity to light and sound. Some people see visual disturbances called an aura beforehand. Cluster headaches are rarer but extremely painful, occurring in clusters around one eye. Caffeine withdrawal and overusing pain medicine can also cause headaches.
When to get help
Most headaches are not dangerous and can be eased with rest, water, food and over-the-counter pain relief. A sudden, extremely severe headache, or one with fever, stiff neck, confusion, weakness or after a head injury, needs urgent medical attention.
Did You Know?
So-called brain freeze, the sharp headache from eating ice cream quickly, happens when cold triggers rapid changes in blood vessels in the roof of the mouth.
This answer is general information, not medical advice. For a personal health question, talk to a doctor.