What are cluster headaches?

Dr. Geoffrey P. Colby, MD
Cluster headache is a miserable disorder that affects both men and women, but usually men. Cluster headaches involve one side of the face, usually in the area around the eye. The episodes can last 30 minutes and up to two hours, and they often come in waves. There are multiple episodes over a period of days or weeks, and then they'll go away for a long period of time. The headaches are often accompanied by redness of the eye, tearing and stuffy nose.
"Cluster headaches," as the name suggests, are headaches that typically occur in groupings over several weeks. They are usually only on one side and can hurt behind the eye, above the eye or in the temporal area. They can last 15 to 180 minutes, occurring up to 8 times a day, every other day or anything in between. They must involve either reddening of the eye, watering of the eye, a stuffy or runny nose, forehead or facial swelling, dilated eye, droopy eye or even swelling of the eyelid, all on the same side usually affected by the pain of the headache.

Cluster headaches are one-sided headaches with stabbing pain through the eye accompanied by eyelid drooping, eye tearing and/or nasal stuffiness/runniness that usually last from 15 minutes to 3 hours. Headaches typically come in "clusters" of attacks happening a few times a day for several weeks in a row. In between clusters the person does not experience any headaches at all. These in-between periods can range from months to years. Cluster headache is thought to come from a part of the brain that is in charge of circadian rhythms called the hypothalamus. Exactly how it creates the pain is unclear.

Cluster headaches are rare. They occur in less than 1 percent of the population, and most cluster headache sufferers are men. Cluster headaches include these symptoms: extremely severe one-sided pain around an eye; pain that lasts from 15 minutes to 3 hours; headaches recur with a frequency ranging from once every other day to 8 times per day. Additional symptoms are typical in cluster headache attacks. Doctors prescribe a variety of prescription medications for treating and preventing cluster headaches.

Cluster headache, although rare, is among the most painful of all headaches. A typical cluster headache begins suddenly, often waking the person from sleep, most commonly between midnight and 2 a.m. The pain is intense, sharp, and penetrating, and it usually occurs behind one eye, which may be teary and bloodshot. The eyelid may droop, and the nostril on that side may first be stuffy and then runny. During a single attack, the symptoms will occur in either the left or right side, but never in both.

Unlike a person with a migraine headache—who tends to lie quietly in bed—someone having a cluster headache attack is likely to pace the floor. The pain is so excruciating that it's tempting to bang your head against a wall. After an hour or two, the pain and other symptoms usually recede, sometimes just as suddenly as they came on. But they tend to recur at the same time day after day.

About 10 times as many men as women have cluster headache. About 90% of those have the episodic form: clusters of one or two headaches a day over a period of two to eight weeks, alternating with headache-free stretches. Usually, the remission time between cluster periods lasts six to 12 months, but it can be as short as a few weeks or as long as several years. The other 10% of people with cluster headache have attacks that continue for at least a year without any remission, which is known as chronic cluster headache.

When given by injection, sumatriptan (Imitrex) relieves about 75% of cluster headache attacks within 15 minutes. The next most effective treatment is inhaling pure oxygen, administered in an emergency room or at home from a portable tank, which can be prescribed by a doctor. If there's no improvement after 15 minutes of inhaling, further oxygen therapy probably won't help.

Cluster headache is the most severe form of primary headache. This involves sudden, extremely painful headaches that occur in "clusters," usually at the same time of the day and night for several weeks. This headache strikes one side of the head, often behind or around one eye, and may be preceded by a migraine-like aura and nausea. The pain usually peaks 5 to 10 minutes after onset and continues at that intensity for up to 3 hours. The nose and eye on the affected side of the face may get red, swollen, and teary. Some people will experience restlessness and agitation, changes in heart rate and blood pressure, and sensitivity to light, sound, or smell. Cluster headaches often wake people from sleep.

Cluster headaches generally begin between the ages of 20 and 50 but may start at any age, occur more often in men than in women, and are more common in smokers than in nonsmokers. The attacks are usually less frequent and shorter than migraines. It is common to have 1 to 3 cluster headaches a day with 2 cluster periods a year, separated by months of freedom from the symptoms. The cluster periods often appear seasonally, usually in the spring and fall, and may be mistaken for allergies. A small group of people develop a chronic form of the disorder, which is characterized by bouts of headaches that can go on for years with only brief periods (1 month or less) of remission. Cluster headaches occur more often at night than during the day, suggesting they could be caused by irregularities in the body's sleep-wake cycle. Alcohol (especially red wine) and smoking can provoke attacks. Studies show a connection between cluster headache and prior head trauma. An increased familial risk of these headaches suggests that there may be a genetic cause.

Treatment options include oxygen therapy, in which pure oxygen is breathed through a mask to reduce blood flow to the brain and triptan drugs. Certain antipsychotic drugs, calcium-channel blockers, and anticonvulsants can reduce pain severity and frequency of attacks. In extreme cases, electrical stimulation of the occipital nerve to prevent nerve signaling or surgical procedures that destroy or cut certain facial nerves may provide relief.

This answer is based on source information from the National Institute of Neurological Disorders and Stroke.

Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
The pain of a cluster headache is often described as an ice pick in the head because of its concentrated stabbing feeling. The name comes from the fact that the headache occurs in a cluster of days over several weeks. The pain is often followed by a runny nose or fever, so they are often known as “histamine headaches." Cluster headaches are common in the winter due to temperature changes.
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Steven A. Meyers, MD
Diagnostic Radiology

Cluster headache is an uncommon headache type that affects men more than women. It is characterized by very severe pain in or behind one eye. The pain typically develops very quickly but when compared to migraine lasts a relatively shorter period of time, 15 to 180 minutes. The attacks also include combinations of eye tearing, eye redness, and a stuffy or runny nose all on the same side as the pain.

These headaches are called cluster headaches because typically they occur in clusters. The headaches may occur daily for several weeks and then they disappear for months or even years at a time.

Angela Lowery
Family Medicine

Cluster headaches are the most painful type of headache. There is intense pain in or around the eye. It is sometimes called the alarm clock headache because it awakens you in the middle of the night.

Cluster headaches, which more commonly affect men, cause headaches that cause pain behind one eye. Cluster headaches do not run in families. While migraines usually concentrate pain on one side of the head or the other, cluster headaches typically cause pain behind one eye or the other.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.