Cluster headaches affect one side of the head (unilateral) and may involve tearing of the eyes and a stuffy nose. The headaches occur repeatedly every day at the same time for several weeks and then go away.

Cluster headaches are a fairly common form of chronic, recurrent headache. Unlike migraines, they affect men more often than women. They can affect people of any age but are most common between adolescence and middle age. There does not seem to be a pattern among families in the development of cluster headaches.

A cluster headache begins as a severe, sudden headache. No specific cause has been found for the disorder, but it appears to be related to a sudden release of histamine or serotonin by body tissues.

The onset is sudden, and it happens most commonly during the dreaming (REM) phase of sleep. Cluster headaches may occur daily for months, alternating with periods without headaches (episodic), or they can recur for a year or more without stopping (chronic). A person may experience alternating chronic and episodic phases.

Some people who experience cluster headaches are heavy smokers. Alcohol use may trigger attacks. Glare, stress, or certain foods may trigger an attack.

• Swelling under or around the eyes (usually one eye, on the same side as the head pain)
• Excessive tears (on the affected side)
• Red eye (on the affected side)
• Rhinorrhea (runny nose) or nasal congestion (typically occurs on only one side of the nose, the same side as the head pain)
• Red, flushed face
• Headache
  • Begins suddenly
  • Commonly begins 2 to 3 hours after falling asleep
  • Steady, sharp pain
  • Burning or boring pain
  • Characteristically occurs on one side of the head
  • May occur in and around one eye
  • May involve one side of the face from neck to temples
  • Pain quickly gets worse, peaking within 5 to 10 minutes
  • Peak pain may last one-half to 2 hours

Cluster headaches may be diagnosed by your health care provider based on the symptoms and a physical examination. Tests may be required to rule out other causes of the symptoms. Examination usually shows no specific neurologic effects except for Horner's syndrome (one-sided eyelid drooping or small pupil) during an attack that is not present between episodes. This can evolve into persistent Horner's syndrome.

An MRI of the head may be done to rule out other pathology.

Treatment does not cure cluster headaches. The goal of treatment is to relieve symptoms. Spontaneous remission may occur, or treatment may be required to prevent headaches.

Smoking, alcohol use, specific foods, and other factors that seem to trigger cluster headaches should be avoided.

A headache diary may be helpful to identify such triggers. When a headache occurs, record the date and the time, list any activities, substances used or consumed within the previous 24 hours, and any other factors that seem significant.

Analgesic medications do not usually relieve the pain from cluster headaches. Generally, they take too long to work -- the headache is usually gone before they take effect.

Inhalation of 100% oxygen often relieves cluster headache for some people, particularly for frequent cluster headaches that occur at night.

Combination or multiple medications may be required to control symptoms of cluster headache. Because response to medications varies, several medications may be tried before a suitable treatment is found. Response can vary over time, so a previously taken effective medication or combination of medications may not have the same effect.

Ergot preparations (containing ergotamine tartrate alone or in combination with other medications) help prevent attacks for some people. The side effects, however, may be severe.

Methysergide maleate may be helpful to relieve pain and prevent attacks. It may also have severe side effects.

Other medications may be used to treat or prevent symptoms. These include the following:

• Antihistamines
• Indomethacin
• Lithium carbonate
• Calcium channel blockers
• Propranolol
• Amitriptyline
• Verapamil
• Methysergide
• Cyproheptadine

All preventive medications should be tapered off slowly during periods of remission (no headache).

Corticosteroid medications such as prednisone may provide short-term relief of cluster headaches in some people. They are not advised for long-term use because of side effects.

Surgery on certain nerve cells near the brain may rarely be recommended if medications are ineffective.

Cluster headaches are not life-threatening and usually cause no permanent structural changes. However, they are chronic and may be painful enough to be debilitating as they are happening, and this may interfere with work or lifestyle. Occasionally, the pain may be severe enough to drive some individuals to attempt suicide. Side effects of medications or surgery may be severe.

• Interference with lifestyle
• Side effects of medications (see the specific medication)
• Permanent muscle weakness in parts of the face or head after surgery
• Decreased sensation in parts of the face or head after surgery
• Horner's syndrome (not a medical problem, but can be distressing due to cosmetic effects)

Call for an appointment with your health care provider if cluster headaches do not respond to treatment, if headaches disturb sleep, if they happen whenever you are active, or are accompanied by other symptoms.

Emergency symptoms include drowsiness, vision changes, changes in movement or sensation, seizures, changes in alertness, and nausea or vomiting.

If prone to cluster headache, stop smoking. Alcohol use and any foods that are associated with cluster headache may need to be avoided. Medications may prevent cluster headaches in some cases.