What are headaches?

A headache is an ache or pain occurring anywhere in the face, head or neck. Headache pain is experienced through pain-sensitive structures around the head and neck including blood vessels, nerves and muscles. Tissues including the eyes, ears and sinuses may also be involved. Headaches can range across the intensity spectrum from mild, tolerable pain to severe pain that prohibits daily activities. Headaches are one of the most commonly experienced causes of pain. They can be occasional, recurrent or chronic in frequency.

The International Classification of Headache Disorders (ICHD) is published by the International Headache Society to classify and diagnose types of headaches. According to this classification system, there are four primary types of headaches: migraines, tension-type headaches, cluster headaches and other primary headaches sensed in the cranial nerves. Different types of headaches may respond to different types of treatments as they originate from various causes and structures.


A migraine is a moderate to severe headache often accompanied by nausea, vomiting, increased sensitivity to sound, and increased sensitivity to light. The severity, duration and frequency of migraine pain vary between people.

There are four phases of a migraine, and all are not necessarily experienced. The first phase, called the prodrome, may occur hours or days before the migraine, and consists of altered mood, excessive sleepiness, stiff muscles and other symptoms. The second phase, called an aura, which may immediately precede the attack, occurs in 20 to 30 percent of migraine sufferers. An aura can be motor or sensory in nature and can include a disturbance of vision such as flashes of light or zigzag lines, or a feeling of pins and needles in the hand, arm, face and mouth. The third phase of a migraine is the pain or headache phase. The pain may occur on one side of the head or both and usually lasts from 4 hours to 3 days. The final phase of a migraine, a postdrome, may occur for some patients. It may include feelings of tiredness, weakness and cognitive difficulties. Six percent of men and 18 percent of women are estimated to experience a migraine headache in their lifetime.