Cluster headaches are a series of relatively short but extremely painful headaches every day for weeks or months at a time. You tend to get them at the same time each year, such as the spring or fall. Because of their seasonal nature, people often mistake cluster headaches for symptoms of allergies or business stress.
We don't know what causes them, but we do know that a nerve in your face is involved, creating intense pain around one of your eyes. It's so bad that most people can't sit still and will often pace during an attack. Cluster headaches can be more severe than a migraine, but they usually don't last as long.
These are the least common type of headaches, affecting less than 1 in 1,000 people. Men get them more than women do. You usually start getting them before you're age 30. Cluster headaches may disappear completely (go into remission) for months or years, but they can come back without any warning.
You get a cluster headache when a specific nerve pathway in the base of your brain is activated. That signal seems to come from a deeper part of the brain called the hypothalamus, where the "internal biological clock" that controls your sleep and wake cycles lives.
The nerve that's affected, the trigeminal nerve, is responsible for sensations such as heat or pain in your face. It's near your eye, and it branches up to your forehead, across your cheek, down your jaw line, and above your ear on the same side, too.
Cluster headaches generally reach their full force quickly -- within 5 or 10 minutes.
The pain is almost always one-sided, and it stays on the same side during a period, the time when you're getting daily attacks. (When a new headache period starts, it might switch to the opposite side, but that's rare.) It's often described as having a burning or piercing quality. It may be throbbing or constant.
A cluster headache lasts a short time -- usually 30 to 90 minutes, but maybe as little as 15 minutes or as long as 3 hours -- then disappears. You'll get one to three of these headaches a day.
Attacks appear to be linked to the circadian rhythm, your body's 24-hour clock. They happen so regularly, generally at the same time each day, that they've been called "alarm clock headaches." One will often wake you up an hour or two after you go to bed. Nighttime attacks can be more severe than the daytime ones.
Most people will get daily headaches for 2 weeks to 3 months; in between these periods, they'll be pain-free for at least 2 weeks. About 2 of every 10 people with cluster headaches have less than 14 headache-free days per year.
Cluster headaches don't make you queasy or throw up. But it's possible for someone with cluster headaches to also get migraines, which can have those symptoms.
Although the pain starts suddenly, you may catch a few subtle cues of the oncoming headache on the affected side:
- Discomfort or a mild burning sensation
- Swollen or drooping eye
- Smaller pupil in the eye
- Eye redness or watering
- Runny or congested nose
- Red, warm face
You may begin to sweat a lot, or light may bother you.
Cluster headaches are more common in people who smoke or are heavy drinkers. During a cluster period, you'll be more sensitive to alcohol and nicotine -- just a bit of alcohol can trigger a headache. But drinking won't trigger one during headache-free periods.
The most successful ways to treat the pain are a shot of sumatriptan (Imitrex) and breathing oxygen through a face mask for 20 minutes. Other drugs used for migraines called triptans may work. Prescription medicines based on the ergot fungus and lidocaine nasal spray might also help.
You should take preventive medicine, unless your headache periods last less than 2 weeks. Your doctor can prescribe medication to shorten the length of the cluster as well as lessen the severity of your attacks, including:
- Divalproex sodium (Depakote)
- Ergotamine tartrate (Cafergot, Ergomar)
- Prednisone, for a short time
- Verapamil (Calan, Covera, Isoptin, Verelan)
When nothing else has worked, surgery may be an option for people who don't get a break from cluster headaches. Most of the procedures involve blocking the trigeminal nerve.