1. Headache and Migraine Triggers Slideshow Pictures
2. A Visual Guide to Migraine Headaches Slideshow Pictures
3. Take the Headaches Quiz

Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

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Medical Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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In this Article

• Headache facts
• What is a headache?
• How are headaches classified?
• What are primary headaches?
• What are secondary headaches?
• What are cranial neuralgias, facial pain, and other headaches?
• What causes tension headaches?
• What are the symptoms of tension headaches?
• How are tension headaches diagnosed?
• How are tension headaches treated?
• What causes cluster headaches?
• What are the symptoms of cluster headaches?
• How are cluster headaches diagnosed?
• How are cluster headaches treated?
• Can cluster headaches be prevented?
• What diseases cause secondary headaches?
• How are secondary headaches diagnosed?
• What are the exams and tests for secondary headaches?
• When should I seek medical care for a headache?
• Headache & Migraine Triggers - Slideshow
• A Visual Guide to Migraine Headaches - Slideshow
• Take the Headaches Quiz!
• Headaches FAQs
• Patient Comments: Headache - Causes
• Patient Comments: Headache - Nausea
• Patient Comments: Headache - Effective Treatments
• Patient Comments: Headache - Symptoms
• Patient Comments: Headache - Remedies
• Find a local Neurologist in your town
• Headache Index

Cluster headaches are so named because they tend to occur daily for periods of a week or more with long periods of time, months to years, with no headache symptoms. They occur at the same time of day, often waking the patient in the middle of the night.

The cause of cluster headaches is uncertain but may be due to a sudden release of the chemicals histamine and serotonin in the brain. The hypothalamus, an area located at the base of the brain, is responsible for the body's biologic clock and may be the location that is the source for this type of headache. When brain scans are performed on patients who are in the midst of a cluster headache, abnormal activity has been found in the hypothalamus.

Cluster headaches also:

• tend to run in families and this suggests that there may be a role for genetics;
• may be triggered by changes in sleep patterns; and
• may be triggered by medications (for example, nitroglycerin, used for heart disease).

If an individual is in a susceptible period for cluster headache, cigarette smoking, alcohol, and some foods (for example, chocolate and foods high in nitrites like smoked meats) also can be potential causes for headache.

Cluster headaches are headaches that come in groups (clusters) separated by pain-free periods of months or years. A patient may experience a headache on a daily basis for weeks or months and then be pain free for years. This type of headache affects males more frequently and often begins in adolescence but can extend to those in middle age.

• During the period in which the cluster headaches occur, pain typically occurs once or twice daily, but some patients may experience pain more than twice daily.
• Each episode of pain lasts from 30 to 90 minutes.
• Attacks tend to occur at about the same time every day and often awaken the patient at night from a sound sleep.
• The pain typically is excruciating and located around or behind one eye.
• Some patients describe the pain as feeling like a hot poker in the eye. The affected eye may become red, inflamed, and watery.
• The nose on the affected side may become congested and runny.

Unlike patients with migraine headaches, patients with cluster headaches tend to be restless. They often pace the floor, bang their heads against a wall, and patients can be driven to desperate measures including contemplating suicide.