Cluster headaches are a rare type of headache. The pain they cause is severe and tends to recur in the same way each time. They occur in groups, or clusters. Each attack lasts about 1 to 3 hours on average. They may occur every other day, up to multiple times a day. Cluster periods are followed by remissions where there are no headaches. These may last months or years.

Men are affected by cluster headaches more than women. The headaches typically start around age 30.

It's not known exactly what causes cluster headaches. They seem to be related to the sudden release of histamine or serotonin in the body.

The following may trigger cluster headaches:

• Alcohol use or smoking cigarettes
• Change to a high altitude
• Bright light
• Exercise or exertion
• Heat, from either the weather or a bath
• Foods that contain nitrates, such as bacon or lunch meat
• Cocaine use

These are common symptoms of a cluster headache:

• Sudden onset of pain, generally around or behind the eye
• Pain builds to a peak in about 10 to 15 minutes
• Restlessness or agitation
• Red or watering eyes
• Nasal congestion
• Sweating on the forehead
• Eyelid drooping or swelling
• Changes in the pupil of the eye during a cluster headache

The symptoms of a cluster headache may look like other health conditions. Always see your doctor for a diagnosis.

Your doctor will diagnose cluster headaches based on your history of a pattern of near-daily headaches that come back again and again for days, weeks, or months.

Two approaches are used to treat cluster headaches:

• Stopping an attack
• Preventing future attacks

To stop or at least control an attack in progress, you may be given high-dose oxygen therapy through a face mask for 15 to 20 minutes. Your doctor may also prescribe an injection of sumatriptan to ease the severe pain of a cluster headache. Sumatriptan is a selective serotonin receptor agonist. This medicine causes blood vessels in the brain to constrict. This eases pain. Other triptans may also be tried if sumatriptan doesn't help.

The second part of cluster headache treatment is to prevent recurrent attacks by using daily medicine. Several medicines are used to prevent cluster headache attacks:

• Verapamil. A medicine that relaxes blood vessels.
• Prednisone. A steroid that reduces inflammation and swelling.
• Lithium carbonate. A medicine that restores the balance of certain brain chemicals.
• Anti-seizure medicines. Medicines that may help reduce the number of cluster headaches.
• Galcanezumab. This is a newer medicine.

A true cluster headache is not life-threatening. It does not cause permanent brain damage. But they tend to be long-term (chronic) and recurrent. They can interfere with your lifestyle or work.

To prevent a cluster headache, it's important to find out what triggers your headaches. Try not smoking and using alcohol. Keep a journal that describes what you were doing, eating, or drinking when the headache started. Bring the journal to your appointments. The journal information may help your doctor prescribe a medicine and a management plan that will help prevent cluster headaches.

Some danger signs may occur with cluster headaches that mean you should get medical care right away. These include:

• Changes in alertness.
• Loss of movement or sensation.
• Drowsiness.
• Nausea or vomiting.
• Seizure activity.
• Changes in vision.

• Cluster headaches occur in groups, or clusters, and each attack lasts about 1 to 3 hours on average.
• They may occur every other day to multiple times a day.
• Cluster periods are followed by remissions that may last months or years.
• Compared with other types of primary headaches, cluster headaches are rare.
• The pain they cause is severe, and they tend to recur in the same way each time
• Finding out headache triggers may help prevent their occurrence.
• A true cluster headache is not life-threatening and does not cause permanent brain damage.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions.