The Cluster Headache: Just Like Clockwork

Like the ringing of an alarm clock, a cluster headache announces itself every morning or night.

If you suffer from cluster headaches, you know that timing is everything. These headaches--called "cluster" because of their pattern of striking in groups or clusters--hit at the same time of day for a period of weeks or months, then vanish as suddenly and as mysteriously as they appeared.

The pain of cluster headaches can be very intense. Most sufferers cannot sit still and will often pace during an acute attack. Often described as having a burning or piercing quality, the pain may be throbbing or constant. The scalp may be tender. Cluster headaches occur more often in men than in women.

Cluster headaches, which are generated by swelling of blood vessels in the head, generally reach their full force within five to 10 minutes after onset. The attacks are usually very similar, varying only slightly from one attack to another.

Malfunction is the trigger

Researchers now believe that cluster headaches, as well as migraines, are triggered by a malfunction of neurotransmitters--in particular, serotonin--which control the action of the blood vessels in the head and neck.

Although the pain of a cluster headache starts suddenly, people usually have a bit of warning that one is on the way. That warning is often a feeling of discomfort or a mild, one-sided burning sensation. Most cluster headaches last only 30 to 45 minutes, but some range from a few minutes to several hours. The headache will disappear only to recur later that day; most sufferers get one to four headaches per day during a cluster period.

Because they occur so regularly, generally at the same time each day, they have been dubbed "alarm clock headaches."

The headache periods can last weeks or months and then disappear completely for months or years. The cluster headache sufferer has pain-free intervals between episodes. Many cluster headaches occur in the spring or autumn. Because of this, cluster headaches are often mistakenly associated with allergies or business stress. The seasonal relationship is unique for each sufferer. In about 20 percent of cluster sufferers, the attacks may be chronic--they are present throughout the year and do not occur in groups, thus making the control of these headaches more difficult.

One-sided pain

The pain of cluster headaches is almost always on one side only and, during a series, the pain remains on the same side. When a new series starts, it can occur on the opposite side. The pain is found behind the eye or in the eye region and may radiate to the forehead, temple, nose, cheek, or upper gum on the affected side. The affected eye may become swollen or droop. The pupil of the eye may contract, and the nostril on the affected side of the head is often congested. Excessive sweating also may occur, and the face may become flushed on the affected side. Unlike migraines, cluster headaches are not associated with gastrointestinal disturbances or sensitivity to light.

During a series, even small amounts of alcohol can bring on an attack. Other substances that cause blood vessel swelling, such as nitroglycerin or histamine, also can provoke an acute attack during a series. Smoking can increase the severity of cluster headaches during a cluster period. During these series, the sufferer's blood vessels seem to change and become more susceptible to the action of these substances. The blood vessels are not as sensitive to these substances during headache-free periods.

For some people, cluster headaches never disappear. These are known as chronic cluster headaches, and people who have this form of cluster headaches don't respond to conventional forms of cluster therapy.

If you get cluster headaches, your doctor will prescribe medicine to cut short the length of the cluster period and decrease the severity of the headaches. The medication prescribed helps regulate the chemistry in the brain.