Cluster headache is a type of severe, recurring pain that is located on one side of the head. It received its name from the clustering, or pattern, of frequent headaches that usually occur.

There are 2 main types of cluster headaches:

  • Episodic—These occur one or more times daily for multiple weeks. The headaches then go away and come back months or years later.
  • Chronic—These occur almost daily with headache-free periods lasting less than a month.
  • Either type of headache may switch to the other type.


    The cause of cluster headaches is not known. It is thought that there is abnormal activation of the area of the brain that is responsible for regulating temperature, blood pressure, hormone release, and sleep. The pain is thought to be caused by a combination of widening of the blood vessels and inflammation of the nerves of the face.

    Other possible causes include:

  • Alcohol use disorder
  • Changes in barometric pressure
  • Changes in sleep pattern
  • Tobacco use disorder
  • Medications, such as nitroglycerin
  • Risk Factors

    Men aged 20-50 years are more likely to get cluster headaches. Other factors that may increase your chance of cluster headaches include:

  • Prior head surgery or head injury
  • Family history of cluster headaches
  • Symptoms

    Cluster headaches may cause:

  • Stabbing, penetrating, burning, or explosive head pain that:     
  • Begins suddenly
  • Is on one side of the head, but not both
  • Often starts around the eye and spreads to the same side of the head
  • Causes facial flushing
  • Can occur daily or almost every day for multiple weeks
  • Can occur 1-8 times per day
  • Lasts 15 minutes to 3 hours
  • Often occurs at about the same time each day
  • May increase in intensity over time
  • May start within 2 hours of going to sleep
  • Can awaken you from sleep
  • Causes an aura—This can include visual disturbance, visual spots, or the inability to move one side of the body.
  • Restlessness and agitation
  • Nausea
  • During the headache, other symptoms may occur on the affected side, including:

  • Stuffy or runny nose
  • Redness or watering of the eye on one side
  • Droopy eyelid
  • Constriction of the pupil of the eye
  • Facial swelling and flushing, sweating
  • Sensitivity to light and noise
  • Symptoms of a Cluster Headache

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    The doctor will ask about your symptoms and medical history. A physical and neurological exam will be done. A neurological exam may include examining:

  • Mental status
  • Cranial nerve functioning
  • Motor and sensory functioning
  • Reflexes
  • Coordination
  • Walking
  • The doctor will ask about the frequency and pattern of your headaches. To help provide answers, you may consider keeping a diary of:

  • When your headaches started and ended
  • What you were doing at the time
  • What you tried to relieve the pain
  • Imaging tests to evaluate the brain include:

  • MRI scan
  • CT scan
  • Treatment

    Treatment aims to reduce the frequency of headaches and relieving pain.

    Lifestyle Changes and Self-care

  • Maintain the same sleep routine. Avoid afternoon naps or sleeping in, which may bring on more headaches.
  • Do not drink alcoholic beverages. Even a small amount of alcohol can trigger a headache during a cluster period.
  • Learn stress management techniques. Stress can bring on a headache.
  • Do not smoke. Tobacco may interfere with medications.
  • Find out what your headache triggers are and take steps to avoid them.
  • Medication

    Medications used to treat migraines often relieve sudden attacks of cluster headaches. These drugs must be taken at the first sign of a headache. Other medications may also be prescribed.

    In some cases, the headache does not last long enough for medications to be helpful. Sometimes, the medications just delay an attack, rather than stop an attack.

    Painkillers, especially opioids, may not be effective during an acute attack.

    Other medications may be given to prevent or reduce the frequency of headaches.

    Oxygen Therapy

    Breathing 100% oxygen for 10-15 minutes often relieves cluster headache pain. This is often viewed as the first-line therapy for cluster headache. The oxygen appears to decrease blood flow to the affected area of the brain. People under age 50 who have episodic cluster headaches seem to benefit most from oxygen therapy.

    Oxygen therapy can be expensive. There are also risks with this therapy.


    As a last resort, some doctors may recommend cutting or destroying a facial nerve to eliminate pain.


    To help reduce your chance of cluster headaches:

  • Maintain a regular sleep routine.
  • Talk to your doctor about how to quit smoking.
  • Avoid alcohol, opioid pain relievers, bright sunlight, and emotional stress.
  • Get moderate physical exercise.
  • Practice relaxation techniques.
  • Take your medication as directed.