A cluster headache is a severe form of headache. It causes debilitating pain that can interfere with a person’s daily life and sleep cycle.

The sharp, penetrating or burning pain associated with a cluster headache usually involves only one side of the head. This pain is most often felt in or around an eye or in the temple. Many times the head pain is accompanied by drooping of the eyelid and nasal congestion on the same side as the pain. 

One of the most painful types of headache, cluster headaches often develop within minutes. Although they offer little warning before they develop, they often occur in cyclical patterns (clusters).  They usually occur at the same time every day. In some people they occur consistently at multiple times every day. These episodes may continue for weeks or months in phases known as cluster periods.

Each individual headache episode may last an average of 45 to 90 minutes. The time between headaches within the same cluster period may last anywhere from a few hours to an entire day. Cluster periods are often followed by periods without headache. This remission period may last for months or years.

Cluster headaches that occur daily for one week to one year, followed by a remission period lasting weeks to years before the development of another cluster period, are known as episodic. Cluster headaches occurring daily for more than a year, with no remission or with pain-free phases lasting less than two weeks, may be described as chronic.

Although the exact cause of cluster headaches remains unknown, researchers have identified a number of factors believed to trigger the headaches including smoking and use of alcohol. Age and sex also appear to play a role. The majority of patients with this condition are men between the ages of 20 and 50.

To diagnose this condition, physicians will review a patient’s medical history and perform a physical examination. Imaging tests such as MRI or CAT scan may be ordered to rule out other potential causes of the head pain.

Cluster headaches cannot be cured. However, a number of treatment methods are used to relieve symptoms, shorten the headache period and prevent future episodes. Treatments include headache medications and, in some cases, surgery.