​Cluster Headache

Cluster headaches are a neurological disorder (that is, a disorder related to the brain) that causes repeated, severe headaches, usually around one side of the head and the eye. You may experience an episode between once to thrice daily during the cluster period, that is, a period of time during which these headaches are active. This period may last from two weeks up to three months. You are likely to suffer from cluster headaches at the same time each year, such as the spring or fall.

A cluster headache is strong enough to awaken you from sleep. Nocturnal attacks (attacks which happen at night) can be more severe than daytime attacks. Cluster headaches can even be more intense than migraines but they do not last as long. During the remission period, the headaches may disappear completely for months or years, but recur without any warning.

The exact cause of cluster headaches is unknown but they occur when a nerve pathway in the brain (known as the trigeminal-autonomic reflex pathway) is activated. This is the main nerve of the face responsible for sensations.

Unlike migraine and tension headache, cluster headache generally isn't associated with triggers such as stress. These are the rarest form of headaches, but men are more likely to develop it than women.