Headache refers to head pain. There are several different types of headache, including:

  • Tension
  • Migraine
  • Cluster
  • Sinus
  • Pseudomotor cerebri

While the precise cause of many headaches remains unknown, several theories exist. The causes of a headache vary depending on the type of headache.

Tension headache refers to head pain associated with stress and muscle contraction. These headaches may occur only occasionally in response to a stressful event. They may also be chronic, occurring frequently. Some tension headaches are nearly constant, with daily pain that may vary in intensity. Tension headaches occur when muscles in the neck, face, and scalp contract and produce pain. The precise cause of this muscle contraction is unknown, but stress, anxiety , depression , eyestrain, and other factors may contribute.

Migraine is a type of recurring headache that involves blood vessels, nerves, and brain chemicals. Sensations such as visual changes, called auras, may precede a migraine. The International Headache Society recently developed a new system that classifies migraines as one of two types: migraine occurring with an aura (formerly called “classic”) and migraine occurring without an aura (formerly called “common"). Migraines may occur several times a week or once every couple of years. Migraines may be so severe that they interfere with your ability to work and carry on normal activities.

An internal or external trigger sets off a process that results in migraine headaches. The exact trigger is often unknown. It is possible that the nervous system reacts to the trigger by conducting electrical activity that spreads across the brain. This electrical activity leads to the release of brain chemicals that make blood vessels swell and become inflamed. Scientists think that it is this inflammatory process that causes the pain and other symptoms of a migraine headache.

Cluster headache is a type of severe, recurring pain that is located on one side of the head. It received its name from the clustering or pattern of frequent headaches that usually occur.

There are two main types of cluster headaches. Either type of headache may convert to the other type:

  • Episodic cluster headaches —(80% of all cases) occur one or more times daily for several months. The headaches then enter a period of remission and come back months or years later.
  • Chronic cluster headaches —(20% of all cases) occur almost daily with, at most, one headache-free week during a year.

The cause of cluster headaches is unknown.

Sinus headaches are associated with inflammation of the sinuses (called sinusitis ). The sinuses are hollow cavities in the skull. Colds and allergies cause inflammation of the nasal passages and can lead to sinusitis. Allergies and viral upper respiratory infections increase nasal secretions and cause tissue lining the nasal passages to swell. This results in nasal congestion and stuffiness. The nasal passages become blocked and normal drainage cannot occur. Secretions that are trapped in the sinuses may become infected with bacteria or, rarely, fungus. The swollen tissues or infection may create pain and pressure.

Pseudomotor cerebri (also known as idiopathic intracranial hypertension) is due to increased pressure around the brain. It is believed that the pressure may be caused by the partially obstructed flow of fluids in the veins. The cause of the obstruction is unclear. This increased pressure causes daily headaches. The pressure in the brain will also increase pressure on the nerves going from the eyes to the brain and less commonly the nerves responsible for eye movements. This could result in permanent vision loss and problems with eye movements. This condition is most common in obese women of childbearing age.

More than 45 million Americans suffer from regularly occurring headaches. More than 28 million of these people experience migraines. Talk to your doctor about headaches you may be experiencing. The doctor can help you understand the cause of your particular headache and work to decrease or eliminate them.

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