Cluster headaches are a rare form of headache notable for their extreme pain and their pattern of occurring in "clusters," usually at the same time(s) of the day for several weeks.
A cluster headache usually begins suddenly with excruciating pain on one side of the head, often behind or around one eye. In some individuals, it may be preceded by a migraine-like "aura." The pain usually peaks over the next 5 to 10 minutes, and then continues at that intensity for up to an hour or two before going away.
People with cluster headaches describe the pain as piercing and unbearable. The nose and the eye on the affected side of the face may also get red, swollen, and runny, and some people will experience nausea, restlessness and agitation, or sensitivities to light, sound, or smell. Most affected individuals have one to three cluster headaches a day and two cluster periods a year, separated by periods of freedom from symptoms.
A small group of people develop a chronic form of the disorder, characterized by bouts of cluster headaches that can go on for years with only brief periods (2 weeks or less) of remission.
Cluster headaches generally begin between the ages of 20 and 50, although the syndrome can also start in childhood or late in life. Males are much more likely than females to develop cluster headaches. Alcohol (especially red wine) provokes attacks in more than half of those with cluster headaches, but has no effect once the cluster period ends. Cluster headaches are also strongly associated with cigarette smoking.
Scientists aren't sure what causes the disorder. 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.
There are headache medications available to lessen the pain of a cluster headache and suppress future attacks:
- Oxygen inhalation and triptan drugs (such as those used to treat migraine) administered as a tablet, nasal spray, or injection can provide quick relief from acute cluster headache pain.
- Lidocaine nasal spray, which numbs the nose and nostrils, may also be effective.
- Ergotamine and corticosteroids such as prednisone and dexamethasone may be prescribed to break the cluster cycle and then tapered off once headaches end.
- Verapamil may be used preventively to decrease the frequency and pain level of attacks.
- Lithium, valproic acid, and topiramate are sometimes also used to prevent cluster headaches
Reference: National Institute of Neurological Diseases and Stroke (NINDS)