Overview of Cluster Headaches


Migraine headachesA cluster headache occurs on one side of the head and may involve a stuffy nose and tearing of the eyes. Cluster headache attacks occur in clusters, which means the patient has them regularly for a period of time.

These attacks are separated by pain-free periods, which can last anywhere from one month to one year. According to the World Health Organization, cluster headache is a primary headache disorder, affecting around 1 in 1,000 adults and 6 men to each 1 woman.

Cause and Triggers of Cluster Headaches

Experts are not sure of the exact cause of cluster headaches. However, they believe these headaches are related to either a sudden release of histamine in the body during an allergy response, or from the release of serotonin, which is a chemical made by brain nerve cells. In addition, men are more affected with cluster headaches than women. The identified triggers for cluster headaches include:

  • Alcohol
  • Cigarette smoking
  • High altitudes (hiking and air travel)
  • Heat (hot baths, weather, cooking)
  • Exertion and physical activity
  • Sunlight and bright indoor lights
  • Street drugs, such as cocaine and methamphetamine
  • Certain medications
  • Foods high in nitrites (preserved meats)

Symptoms of Cluster Headaches

A cluster headache starts as a sudden, severe pain, which occurs usually 2 to 3 hours after the patient falls asleep. The pain can be Headache-stock-picture2sharp, burning, and steady, felt on one side of the face (neck to temple), and involve the eye. In addition, the headaches tend to occur during the same time each day. Associated symptoms include:

  • Excessive tearing
  • Swelling around or under the eye(s)
  • Runny and/or stuffy nose on the painful side of the head
  • A red, flushed face
  • A red eye(s)

Diagnosing Cluster Headaches

To diagnose cluster headaches, and rule out other conditions, the doctor will conduct a medical history and physical examination. In addition, certain laboratory and diagnostic tests are used, including:

  • Complete blood count (CBC)
  • Sedimentation rate (ESR)
  • Sinus x-rays
  • Computerized tomography (CT)
  • Magnetic resonance imaging (MRI)

Treatments for Cluster Headaches

  • Occipital nerve block (ONB) – The occipital nerve lies on the top of the scalp. The ONB involves an injection of an anesthetic into the back of the head. This provides several weeks of pain relief.

Occipital Nerve Block

  • Sphenopalatine ganglion block – This procedure involves an injection of a numbing agent (lidocaine) through the nostril or cheek. The area targeted is the sphenopalatine ganglion, which is the group of nerves at the base of the brain near the back of the throat. Studies show that this procedure is effective for acute and chronic head and face pain.


  • Oxygen – Inhalation of 100 percent oxygen through a mask has been proven to help relieve the pain of cluster headache.


  • Injectable medicines – Sumatriptan (Imitrex) is an injectable drug used to abort the headache. Octreotide (Sandostatin) is a synthetic brain hormone used for cluster headache.


  • Prevention – To prevent cluster headaches, several medications are used. These include calcium channel blockers (Verelan and Calan), corticosteroids (prednisone), ergotamine, melatonin, and lithium carbonate.



World Health Organization (2012). Headache disorders. Retrieved from: http://www.who.int/mediacentre/factsheets/fs277/en/

Rozen TD & Fishman RS (2012). Cluster headache in the United States of America: demographics, clinical characteristics, triggers, suicidality, and personal burden. Headache, 52(1), 99-113. doi: 10.1111/j.1526-4610.2011.02028.x.