A cluster headache is an extremely painful headache that is usually situated on one side of the head, behind the eye and there is often sinus congestion on one or both sides at the same time as the headache occurs. Some people experience a cluster headache several times per day in the worst cases. The pain of a cluster headache far outweighs that of a regular headache, and it is even more painful than most migraines.

Cluster headaches are nowhere near as common as migraines. It is estimated that less than 70 in one hundred people will suffer from cluster headaches. But for the few people who do suffer from this debilitating condition, it can be life changing and have a negative effect upon every aspect of their life. Unless you know what triggers your headaches you may be hesitant to continue your regular daily life.

There are 2 types of cluster headache: Those that occur every few months (episodic) and those that occur very regularly such as several times per week or even per day (chronic). Chronic cluster headache sufferers get very little reprieve and are desperately searching for treatments.

A cluster headache generally occurs on one side of the head at any one time, but it can afflict the other side of the head in future attacks. Localized pain around the eye can lead people to believe they are suffering from severe eyestrain however the severity of the pain indicates that it is more than just eye strain causing the problem. The cause of a cluster headache is unknown but research is always being conducted to find a common thread between sufferers.

Other symptoms that can occur before and during a cluster headache include:
- Pain in the temple, teeth, nose, chin or jaw
- Drooping eyelid
- Tearing of the eye
- Flushing face
- Sinus congestion

A cluster headache may last from anywhere from 15 minutes up to several hours. they are called cluster headaches as they group together to occur several times per day or week for a period time – generally for between 1 week and 4 months at a time, they may then not occur for months or even years.