Headache, Cluster - Cluster headache, also known as histamine headache, is a specific vascular headache syndrome. Attacks usually are severe and unilateral and typically are located at the temple and periorbital region. Each headache is brief in duration, typically lasting a few moments to 2 hours. Cluster refers to a grouping of headaches, usually over a period of several weeks.

At one time or another, almost everyone has had a headache. Some headaches are only moderately painful, while others are severe and disabling. No matter what kind of headache you have, you'd rather be without it.

In most cases headache pain, even severe headache pain, is not the result of any underlying disease. In fact, the vast majority of headaches are primary headaches - headaches that aren't caused by a specific medical condition. These include migraines, tension-type headaches and cluster headaches.

Screening and diagnosis

Cluster headaches have a characteristic type of pain and pattern of attacks. A diagnosis depends on your description of the attacks, including your pain, the location and severity of your headaches, and associated symptoms. The frequency and duration of your headaches also are important factors.

If you have chronic or recurrent headaches, your doctor may try to pinpoint the type and cause of your headache using certain approaches.

Examinations and tests

• Neurologic examination. A neurologic examination may help your doctor detect physical signs of a cluster headache. Sometimes the pupil of your eye may appear smaller or your eyelid may droop, even between attacks.

• Imaging tests. If you have unusual or complicated headaches or an abnormal neurologic exam, you may undergo other diagnostic testing to rule out other serious causes of head pain, such as a tumor or aneurysm. Two common brain-imaging tests are computerized tomography (CT) and magnetic resonance imaging (MRI) scans. A CT scan uses a series of computer-directed X-rays to provide a comprehensive view of your brain. An MRI doesn't use X-rays. Instead, it combines magnetism, radio waves and computer technology to produce clear images of your brain.

Headache tracking
One of the most helpful things you can do is keep a headache journal for at least a 2-month period. Each time you get a headache, jot down the following information:

• A description of the pain

• The severity of the pain

• The location of the pain

• The duration of the pain

• Any medications you're taking

A headache journal can offer valuable clues that may help your doctor diagnose your particular kind of headache and discover possible headache triggers.