Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Migraines & Headaches Health Center

Font Size

Cluster Headache

It is possible that the main title of the report Cluster Headache is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


Disorder Subdivisions

General Discussion

Cluster headaches (CH) are an uncommon, severe form of primary neurovascular headaches. CH are the most painful form of headaches, with the pain occurring on one side of the head and behind or above the eye or at the temple most commonly. The pain has been described as searing, burning and stabbing. The age of onset of CH is most often between 20 and 40, and they are more common in men than women with a ratio of 2:1. CH attacks also include one or more cranial autonomic symptoms (CAS) on the same side of the head as the pain (ipsilaterally) such as red eye (conjunctival injection), eyelid swelling (edema), forehead and facial sweating, tearing (lacrimation), abnormally small size of the pupil (miosis), nasal congestion, runny nose (rhinorrhea), and drooping eyelid (ptosis). CH is divided into episodic and chronic. Episodic cluster headache patients usually suffer from 1 to 4 short headaches a day that can individually last between 15-120 minutes when they are having a series of attacks. These attacks (cluster periods) last for weeks or months and are separated by months or years of remission periods where the patients are pain-free. Chronic cluster headache patients suffer without remissions for 1 year or more or with remissions so brief they do not even span a month. Less than 20% of cluster headache patients have the chronic form. It is not yet clear what causes CH, but scientists have discovered a lot of recent evidence that links it to the part of the brain called the hypothalamus. There is no cure, and treatment is determined on an individual basis. However, the two most effective types of acute or symptomatic treatment, high-flow inhaled oxygen and injections of subcutaneous sumatriptan, have been proven to be effective in reducing the pain from CH.

Cluster headaches were first completely described by the London neurologist Wilfred Harris in 1926. At that time, it was believed that nearly 90% of CH patients were men, while women instead suffered with migraine headaches. Although it has been confirmed that men are more at risk for developing CH, that ratio has decreased significantly. Researchers theorize that this is because women have long been misdiagnosed with migraines instead. Treatment for migraine headaches differ in several ways from CH, so an accurate diagnosis is important.


National Headache Foundation
820 N. Orleans
Suite 411
Chicago, IL 60610-
Tel: (312)274-2650
Fax: (312)460-9049
Tel: (888)643-5552

NIH/National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
Tel: (301)496-5751
Fax: (301)402-2186
Tel: (800)352-9424
TDD: (301)468-5981

American Council for Headache Education
19 Mantua Road
Mount Royal, NJ 08061
Tel: (856)423-0043
Fax: (856)423-0082
Tel: (800)255-2243

Organization for Understanding Cluster Headaches (O.U.C.H.)
c/o Sandy Cullen P.O. Box 902
Jamestown, NC 27282
Tel: (214)783-1899

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

For a Complete Report:

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated: 5/29/2012
Copyright 1989, 1997, 1999, 2000, 2002, 2012 National Organization for Rare Disorders, Inc.

WebMD Medical Reference from the National Organization for Rare Disorders

Last Updated: May 28, 2015
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Today on WebMD

Business woman with hand on face and eyes closed
What aura looks like, triggers, and more.
woman with migraine
Get the truth about migraines.
headache in the bedroom
Keep headaches from ruining your sex life.
woman with hands on head
Test your knowledge of triggers, types, and more.
woman with migraine
drinking coffee
Migraines Headaches Basics
acupuncture needles in woman's back
Tired young man
spraying perfume
man with a headache
headache in the bedroom