Causes of Cluster Headache
The exact causes of cluster headaches are unknown. However, it is believed to originate from hypothalamus. Cluster headaches take place when a nerve pathway, called as trigeminal-autonomic reflex pathway is activated from the base of the brain. The activation of this trigeminal nerve takes place from the hypothalamus. Recent imaging studies have linked over-activation or stimulation of the hypothalamus to a cluster attack.
The trigeminal nerve is the chief facial nerve for sensations.

The activated trigeminal nerve causes the eye pain connected with cluster headaches. The trigeminal nerve in turn, stimulates a group of nerves to cause eye tearing & redness and nasal congestions linked to cluster attacks.
Cluster headaches are not caused by serious brain conditions like brain-tumor or aneurysm.
The cluster attacks might be triggered by-
- Alcohol
- Cigarette smoking
- High altitudes (trekking, mountaineering or air travel)
- Bright, flashy lights including sunlight
- Over-exertion
- Intense Heat (hot climate, kitchen heat or hot baths)
- Foods high in nitrites (Eg: bacon or other preserved meats)
- Certain medications
- Cocaine
