As those who suffer from them know, cluster headaches are like no others. They are rated as one of the most painful headaches a person can experience. They come and go, but when a person is experiencing a cluster cycle, the headaches can be debilitating.
Researchers are not sure how cluster headaches are triggered. There are several signaling molecules known to be involved, like serotonin and calcitonin gene related peptide. And there are several brain areas known to be involved, like the trigeminal nucleus and the hypothalamus. But exactly how these signaling molecules and brain areas interact, and exactly how the triggers start a cluster headache, is not clear.
Cluster Headaches and Biological Cycles
Cluster headaches generally occur in cyclical patterns. For many people, there is a daily cycle and a yearly cycle. The daily cycles seem to be influenced by triggers, but the yearly cycles don’t.
The daily cycle refers to headaches that start at the same time each day. One person with cluster headache may have headaches every day at ten o’clock at night; another person may have headaches every day at three o’clock in the morning. In one study of over 1,000 people with cluster headache [link: https://headachejournal.onlinelibrary.wiley.com/doi/full/10.1111/j.1526-45610.2011.02028.x], over 80% of cluster headache sufferers had headaches at the same time each day. Triggers for cluster headache can cause an extra attack outside of the regular timing of the headache.
The yearly cycle refers to the fact that, for many people, the headaches come in bunches. Ninety percent of people with cluster headache will have headaches every day for weeks to months, then will have no headaches for months to years. This is where “cluster” headache gets its name. These yearly cycles also occur like clockwork for some people: many have a cluster period every spring or fall. Triggers for cluster headache have no effect in the cluster-free periods. They do not seem to bring on a cluster headache like they would during the cluster period.
Cluster Headache Triggers
It can be a challenge to pinpoint a person’s cluster headache triggers. What triggers one person’s headache may be different from another. Some things that have been identified as possible cluster headache triggers are:
- Alcohol. Alcohol is the most well-known trigger. Beer is the most common, but any type of alcohol (beer, wine, liquor) can cause an extra cluster headache in some people. Most say that the cluster headache will start within two hours of drinking alcohol.
- Nitroglycerin. This heart medication is known to trigger an extra cluster headache.
- Heat, including hot weather and hot baths.
- Exercise. For some people exercise may trigger a cluster headache. This may be related to heat, as exercise will increase body temperature.
- High altitude. For some, even plane flights can trigger an attack.
- Bright light, like sunlight.
- Weather changes.
This is not a complete list and research into what may trigger a cluster headache is ongoing.
Help in Identifying Your Triggers
A headache diary can be helpful in identifying triggers. Information about when your headaches hit and what your daily activities are may be useful for both you and your doctor. Some things to include in your diary are:
- What time your headaches occur.
- All medications you take, including over-the-counter meds and dietary supplements.
- When you drink an alcoholic beverage and how many beverages you consume at one time.
- When and how much your exercise.
- When you get overheated.
- Any plane trips.
How You Can Help
Research on the cause of cluster headaches and what triggers them, and cures for all types of debilitating headaches is ongoing. The best way you can help is by contributing to organizations that further this study. One such organization is the Will Erwin Headache Research Center. The Center funds research with the hope that triggers for cluster headaches can be more clearly identified so that those around the world can find relief from their suffering.
The Center focuses on finding a cure for all types of headaches. Donations to help fund research are always welcome. Donations go to support The Memorial Hermann Health System and The University of Texas Health Science Center at Houston (UTHealth) Medical School.