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What are cluster headaches?

Cluster headaches can be extremely painful, but treatment can help.

Cluster headaches are a rare but severely painful type of headache that strikes repeatedly over the course of weeks or months and then disappears for a while—usually months or even years.

More common among men than women, cluster headaches occur nearly every day—or several times a day—and last anywhere from 30 minutes to several hours. Because cluster headaches often strike at night or early in the morning, they are sometimes called "alarm clock headaches."

A piercing pain

Cluster headaches are marked by attacks of excruciating, stabbing pain, which can be throbbing or constant. Often described as a burning or piercing sensation, the pain may be so intense that a person can't sit still and may pace around the room. Sometimes people may even try to ease the pain by banging their heads against furniture. Don't be embarrassed to tell your doctor about your attempts to ease headache pain, the American Academy of Family Physicians (AAFP) says. Talking about it could help your doctor better judge how severe your headaches are.

The pain of cluster headaches almost always strikes on one side of the head and may radiate to the forehead, temple, nose, cheek or upper gum. Other symptoms may occur on the affected side as well, such as:

  • Eye tearing or redness.
  • Swollen or droopy eyelid.
  • A runny or stuffy nose.
  • Facial flushing and sweating.

Headache triggers

The cause of cluster headaches is unknown. But experts have found that substances that cause blood vessels to swell—including nitroglycerin, smoking and even small amounts of alcohol—can trigger an attack during a "cluster period."

Stress can also bring on attacks, according to the AAFP. So during a cluster period, it's important to:

  • Try to remain calm.
  • Follow your usual routine.
  • Avoid changing your sleep pattern.  

Treatment options

Several treatments can help relieve and prevent cluster headaches, according to the AAFP. These include:

  • Medications that are taken when an attack starts to help relieve symptoms.
    Note: Oral medicines (taken by mouth) may work too slowly to relieve cluster headaches, so doctors often prescribe drugs that are taken by nasal spray, as an injection ("shot") or as a rectal suppository.
  • Oxygen. Breathing 100% oxygen through a face mask at the first sign of an attack may help ease symptoms.
  • A local anesthetic (numbing medicine) in the nose.
  • Medications that are taken daily to help reduce the frequency and severity of cluster headaches. You may need to take some of these medicines for several weeks to reach an effective dose, so it's important to take the drugs exactly as your doctor prescribes.

If you think you are having cluster headaches, be sure to see your doctor. Preventive medicines can help reduce the number of headaches during cluster periods. And when a cluster headache does occur, you can take other medicines that significantly shorten the headache and ease its severity, according to the AAFP.

Reviewed 11/1/2022

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