The exact cause of cluster headaches is unknown, but abnormalities in the hypothalamus likely play a role. Cluster attacks usually occur with clocklike regularity during a 24-hour day, and the cycle of cluster periods often follows the seasons of the year.

These patterns suggest that the body's biological clock is involved. In humans, the biological clock is located in the hypothalamus, which lies deep in the center of your brain.

Abnormalities of the hypothalamus may explain the timing and cyclical nature of cluster headache. Imaging studies have detected increased activity in the hypothalamus during the course of a cluster headache.

Unlike migraine and tension headache, cluster headache generally isn't associated with triggers, such as foods, hormonal changes or stress. Some people experience an aura or nausea similar to those experienced with migraine headaches.

Once a cluster period begins, however, consumption of alcohol can quickly trigger a splitting headache. For this reason, many people with cluster headache avoid alcohol for the duration of a cluster period.

Other possible triggers include the use of medications such as nitroglycerin, a drug used to treat heart disease.

Jun. 04, 2013

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