A headache or cephalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is notsensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the pain-sensitive structures around the brain. Several areas of the head and neck have thesepain-sensitive structures, which are divided in two categories: within the cranium (blood vessels, meninges, and the cranial nerves) and outside the cranium (the periosteum of the skull, muscles, nerves, arteriesand veins, subcutaneous tissues, eyes, ears, sinuses and mucous membranes).
There are a number of different classification systems for headaches. The most well-recognized is that ofthe International Headache Society. Treatment of a headache depends on the underlying etiology or cause, but commonly involvesanalgesics.
The most common types of headache are the "primaryheadache disorders", such tension-type headache and migraine. They have typical features; migraine, for example, tends to be pulsating in character, affecting one side of the head, associated with nausea,disabling in severity, and usually lasts between 3 hours and 3 days. Rarer primary headache disorders are trigeminal neuralgia (a shooting face pain),cluster headache (severe pains that occur togetherin bouts), and hemicrania continua (a continuous headache on one side of the head).
Headaches may be caused by problems elsewhere in the head or neck. Some of these are not harmful,such as cervicogenic headache (pain arising from the neck muscles). Medication overuse headache may occur in those using excessive painkillers for headaches, parodoxically causing worsening headaches.A number of characteristics make it more likely that the headache is due to potentially dangerous secondary causes; some of these may be life-threatening or cause long-term damage. A number of...