Pain in the head is caused by dilation of cerebral arteries or muscle contractions or a reaction to drugs. Headaches are one of the most common types of pain afflicting many people around the world and can range from mild to moderate to severe.

Common types of headaches:

• Cluster headache, histamine headache: a painful recurring headache associated with the release of histamine from cells.

• Hemicrania, megrim, migraine, sick headache: a severe recurring vascular headache; occurs more frequently in women than men.

• Sick headache: a headache accompanied by nausea.

• Sinus headache: a headache resulting from congestion or infection in the paranasal sinuses.

• Tension headache: a headache located at the back of the head; usually caused by body tension resulting from overwork or psychological stress.