Causes of Cluster Headaches
While it's not known exactly why cluster headaches occur, certain factors are known to increase your risk of developing this type of headache. For example, having a family history of cluster headaches can put you at a higher risk. There is also a possibility that cluster headaches are caused by irregularities in the body's circadian rhythms.
What Causes Cluster Headaches?The exact cause or causes of cluster headaches are not known. Cluster headaches have not been linked to hormones or foods, as migraines have (see Migraine Triggers or Migraine Food Triggers).
Research studies have, however, turned up several clues regarding possible causes. The tendency of cluster headaches to occur during the same time(s) from day to day, and more often at night than during the daylight hours, suggests they could be caused by irregularities in the body's circadian rhythms, which are controlled by the brain and a family of hormones that regulate the sleep-wake cycle.
Also, despite not knowing the underlying cause, researchers do know that two parts of the body are involved in cluster headaches -- the trigeminal nerve and the autonomic nervous system. The trigeminal nerve supplies sensation to the face. When stimulated, it can cause pain in and around the eye. The autonomic nervous system controls a number of bodily functions, including heart rate, digestion, and body temperature. Stimulating the autonomic nervous system causes other cluster headache symptoms, including eye tearing and nasal discharge.
Cluster Headache Risk FactorsWhile not specific cluster headache causes, there are certain factors that can increase a person's risk for developing this type of headache. Specific cluster headache risk factors include:
- Family history of cluster headaches (up to a 14-fold increased risk)
- Hazel eyes
- Disruption of normal sleep patterns
- Certain medications (such as nitroglycerin)
- Being a heavy smoker or drinker.
Paradoxically, both nicotine (which constricts arteries) and alcohol (which dilates them) trigger cluster headaches. In fact, alcohol can bring on a cluster headache in more than 50 percent of people who experience cluster headaches; this sensitivity to alcohol stops when the cluster headache ends. The exact connection between nicotine, alcohol, and cluster headaches is unknown.