A disorder resulting in a severe unilateral headache , that may be associated with tearing, nasal congestion and eye injection. It occurs in clusters, happening repeatedly every day at the same time for possibly several weeks and then remitting. Unlike migraines , they affect men more often than women. They occur anytime, most commonly from adolescence to middle age. There does not seem to be a pattern among families in the development of cluster headaches.
Cluster headaches occur as a severe, sudden headache.
No specific cause has been found for the disorder, but it appears to be related to a release of histamine, serotonin , or similar substances from body tissues. A person may experience alternating chronic and episodic phases. Some people who experience cluster headaches are heavy smokers. Alcohol use may trigger attacks. In some people, glare, stress , or certain foods may trigger an attack.