Even thinking about this headache's name nearly gives you a headache. Cluster headaches seem to come out of nowhere and cause excruciating pain, usually on one side of the head. They feel most intense around the temple area and create an unsettling sense of pressure directly on your eye.
Cluster headaches are rare, and they usually last about an hour. "Cluster" refers not to the location of the headache pains, but to the period of days, weeks or months over which the headaches will occur. After you've suffered through a cluster of them, they'll often suddenly go away for months or even years.
Researchers are getting closer to understanding cluster headaches, and they know the hypothalamus -- the area of your brain that controls your autonomic nervous system and regulates hormones, sleep, libido, breathing and other automatic body processes -- becomes active when they occur, but they don't know why. When the hypothalamus acts up during these episodes, it stimulates a nerve pathway along the base of the brain, causing eye pain. Blood vessels on the surface of the brain swell, causing the squeezing sensation.
If you get cluster headaches, cut out drinking and smoking to give yourself a better shot at a cluster-headache-free existence. Interestingly, oxygen therapy -- breathing pressurized oxygen through a mask for a few minutes -- can help shrink swollen blood vessels. Extreme cases may call for surgery to block the trigeminal nerve, which triggers the pressure in your eye.
On the next page: a thousand curses upon this dreaded type of headache.