A headache is pain in the head or upper neck.
There are four major types of headache: vascular, muscle contraction (tension), traction, and inflammatory.
The most common type of vascular headache is a migraine. Migraine headaches are usually characterized by severe pain on one or both sides of the head, nasuea, and, at times, disturbed vision. Women are more likely than men to have migraine headaches.
Other kinds of vascular headaches include "cluster" headaches, which cause repeated episodes of intense pain, and headaches resulting from high blood pressure. Muscle contraction headaches appear to involve the tightening or tensing of facial and neck muscles, while traction and inflammatory headaches are usually symptoms of other disorders, ranging from stroke to sinus infection. Like other types of pain, headaches can serve as warning signals of more serious disorders.
This is particularly true for headaches caused by rapidly stretching or rupturing weakened blood vessels (aneurysms), those caused by infection (infectious meningitis) as well as those resulting from diseases of the sinuses, spine, neck, ears, and teeth.