Cluster headache (CH) is a neurological disorder characterized by recurrent, severe headaches on one side of the head, typically around the eye. There are often accompanying autonomic symptoms during the headache such as eye watering, nasal congestion and swelling around the eye, typically confined to the side of the head with the pain.
The cause of cluster headaches is unknown. Cluster headache belongs to a group of primary headache disorders, classified as the trigeminal autonomic cephalalgias or (TACs). Cluster headache is named after the demonstrated grouping of headache attacks occurring together (cluster). Individuals typically experience repeated attacks of excruciatingly severe unilateral headache pain. Cluster headache attacks often occur periodically; spontaneous remissions may interrupt active periods of pain, though about 10–15% of chronic CH never remit
While there is no known cure, cluster headaches can sometimes be prevented and acute attacks treated. Recommended treatments for acute attacks include oxygen or a fast acting triptan. Primary recommended prevention is verapamil. Steroids may be used as a transitional treatment and may prevent attack recurrence until preventative treatments take effect. The condition affects approximately 0.1% of the general population at some point in time and 0.05% in any given year. Men are affected about four times more often than women