Headache

Migraine is a serious type of headache characterized by episodic attacks. It usually presents as a throbbing or pulsating pain on one side of the head and may include other symptoms such as nausea, vomiting, and sensitivity to light, sound, or smells. The exact triggers of migraines are still not well understood. However, it is known to be a complex brain condition involving the expansion and narrowing of blood vessels due to disturbances between nerve pathways and blood circulation in the brain. Genetics also appear to play a role in the development of migraines.

Cluster headaches are another type of episodic headache. Although less common, they are extremely painful and considered a severe form of migraine. The pain is localized around one eye, which may become red, swollen, and watery. Other symptoms can include a runny nose and sweating on the forehead or face. Cluster headache episodes can last for weeks, or in some cases, months. Individual attacks generally last no more than three hours, with pain so intense that sufferers often feel the need to move around to cope with it. 

The exact cause of cluster headaches remains unknown. Because the pain centers behind the eye, where the trigeminal nerve (the fifth cranial nerve) is located, it is believed that this nerve may play a significant role in the condition.