Cluster Headaches Fast Facts

Cluster headaches are excruciating headaches that occur in attacks that usually last 1-3 hours. The attacks frequently occur, sometimes multiple times a day.

Periods of frequent headaches may be followed by periods of remission that last months or years.

Cluster headaches do not cause permanent brain damage, but their frequent, extreme pain can cause significant impairment of a person’s daily functioning.

The headaches are most common in young adults but can affect anyone.

United Brain Association

The headaches are most common in young adults but can affect anyone.

What is Cluster Headaches?

Cluster headaches are severe chronic headaches that occur in groups or clusters. The pain associated with cluster headaches is more severe than any other type of headache. They are relatively rare, affecting only about 1 in 1,000 people.

Cluster headache attacks vary in length, but a particular headache can last anywhere from 15 minutes to an hour or more. During active periods, the attacks may occur several times a day or be as infrequent as every other day.

Some people experience periods of remission following periods of frequent headaches. These remission periods may last for months or years. However, about 20% of people with cluster headaches experience chronic, ongoing headaches without remission.


The experience of a cluster headache attack varies from person to person. Still, a typical pattern involves pain concentrated on one side of the head, usually behind the eye, that builds in intensity over just a few minutes. Symptoms of an attack can include:

  • Burning, piercing, or “boring” pain
  • Pain on one side of the head
  • Pain centered behind or near the eye
  • Pain that comes on suddenly and builds quickly
  • Red, watering eyes
  • Dropping or swelling of the eyelid
  • Sweating
  • Nasal congestion
  • Agitation or restlessness

What Causes Cluster Headaches?

Scientists don’t know precisely what causes cluster headaches, but research indicates that they are neurological, meaning that some brain function or brain chemistry problem is the root cause. Cluster headaches may also run in families, which suggests that there might be a genetic component that is inherited.

Although the exact mechanisms in the brain that cause cluster headaches are still unknown, there seem to be environmental or physiological triggers that can sometimes bring on an attack. These triggers vary from person to person, but common triggers include:

  • Smoking
  • Alcohol consumption
  • Poor sleep habits
  • Change in altitude
  • Exposure to bright light
  • Exposure to heat
  • Chemical food additives. Some people seem sensitive to nitrates found in bacon and other processed meats.
  • Exercise or exertion
  • Change of seasons
  • Sleep apnea

Is Cluster Headaches Hereditary?

Some people with cluster headaches have a family history of the disorder, strongly suggesting that there is a genetic component to the headaches. Researchers haven’t yet figured out exactly which genes may increase the risk of developing cluster headaches, but studies suggest that genes may play a role in 3-7% of cases of the disorder.

How Is Cluster Headaches Detected?

A key to effectively treating a cluster headache attack is recognizing when an attack is beginning. Treatments can be effective when administered while the attack is in progress.

Because the symptoms of cluster headaches can be similar to those of other severe, potentially life-threatening neurological conditions, it is essential to seek medical treatment if you or a loved one experiences any of the symptoms of the disorder.

How Is Cluster Headaches Diagnosed?

To diagnose cluster headaches, doctors look for a pattern of symptoms, risk factors, and family history. Because the symptoms of migraines often closely resemble the signs of other severe neurological problems, your doctor will likely focus on ruling out those other problems before moving on to treatment for cluster headaches.

Diagnostic steps may include:

  • A physical exam. This exam aims to rule out specific physical conditions that could be causing the symptoms.
  • Blood and laboratory tests. These tests will examine the patient’s blood chemistry for issues causing the symptoms.
  • MRI scans. An MRI uses a strong magnetic field to create images of a patient’s brain and circulatory system. In addition, a doctor may call for an MRI scan to rule out other problems that may be causing your headaches.
  • CT scans. A CT scan uses X-rays to create images of your brain. Again, your doctor may prescribe a CT scan to look for other problems–such as a tumor, bleeding, or infection–that could be causing your symptoms.


How Is Cluster Headaches Treated?

Treatment for cluster headaches usually involves medications, and the medicines prescribed generally fall into one of two categories. Acute-treatment medications are taken during an attack, and their goal is to lessen the severity of symptoms or decrease the duration of the attack. Preventive medications are intended to prevent cluster headaches from occurring or to reduce their severity when they do occur.

Acute-Treatment Medications

Medications taken during attacks are most effective when administered at the earliest possible sign of a cluster headache.

Commonly used acute treatments include:

  • Sumatriptan. This injected medication often stops an attack within minutes.
  • Dihydroergotamine or zolmitriptan. These medications may also stop an attack.
  • High-flow oxygen. Administering supplemental oxygen through an oxygen mask may stop an attack in some cases.

Preventive Medications

Preventive medications are prescribed to prevent future cluster headache attacks, shorten attacks, or make attacks less severe. Commonly prescribed preventive medications include:

  • Verapamil
  • Prednisone
  • Lithium carbonate

Other Medications and Treatments

Doctors may prescribe other medications or treatments if the more commonly prescribed treatments are not effective. These treatments may include:

  • Calcium channel blockers
  • Divalproex sodium
  • Melatonin
  • Topiramate
  • Calcitonin gene-related peptide (CGRP) monoclonal antibody
  • Vagus nerve stimulation (VNS), a non-invasive treatment that delivers an electrical current to the vagal nerves
  • Occipital nerve block, which involves injecting an anesthetic to numb a nerve in the back of the head

How Does Cluster Headaches Progress?

Cluster headaches themselves do not cause any permanent brain damage or physical complications. However, people with chronic headaches are at risk for significant impairment of their daily functioning and the possibility of mental health-related complications of the disorder. In addition, a significant percentage of people with cluster headaches do not experience remission; they get little relief from the symptoms over a long period of time.

How Is Cluster Headaches Prevented?

The best preventive strategy for cluster headaches is avoiding the triggers that are known to precede attacks. Stopping smoking and avoiding alcohol may help prevent attacks in many cases.

Aside from avoiding triggers, a few general lifestyle strategies may help prevent cluster headaches from happening. Not all of these strategies will work for everyone, and even if a strategy works for you sometimes, it might not be able to stop every attack.

  • Explore relaxation or meditation techniques. These techniques will also help lower your stress level and decrease the frequency or severity of your migraines.
  • Get plenty of sleep. Disruptions in sleep schedules may trigger headaches, and staying well-rested can help prevent them. Aim for a consistent sleep schedule, and avoid sleeping too much.
  • Don’t skip meals. Maintain a consistent eating schedule, too, as skipping meals is a common migraine trigger.
  • Use a headache diary. Write down the details of every headache you experience, including what you did before the headache began and any symptoms you noticed. The log can help you to recognize–and avoid–any triggers that you might otherwise miss.

Cluster Headaches Caregiver Tips

During a cluster headache attack, sufferers are likely unable to do even the simplest tasks for themselves. As a caregiver, you have the opportunity to make the experience as bearable as possible, but you should also know when the best thing you can do is step aside. When someone you love is experiencing a cluster headache, keep these tips in mind:

  • Be on hand and ready to help. Be prepared to get medication, water, an ice pack, or anything else the sufferer needs.
  • Run interference. The sufferer is likely extremely sensitive to light and sound, so you can help by providing a dark, quiet environment. Draw the curtains and limit visitors.
  • Know when to stay out of the way. The pain of the cluster headache is intense, and sometimes the sufferer will simply want to be left alone. Stay close by, but respect your loved one’s need for quiet solitude.
  • Don’t take it personally. The pain is also likely to make the sufferer irritable, and she may express frustration with you. Understand the pain is real, and the frustration is caused by the symptom, not you.
  • Learn as much as you can about cluster headaches. It will help you to be empathetic and an effective caregiver.

Many people with migraines also suffer from other brain-related issues, a condition called co-morbidity. Here are a few of the disorders commonly associated with migraine disorder:

Cluster Headaches Brain Science

Researchers are pursuing the idea that structural and functional differences in specific parts of the brain may be the reason that some people experience cluster headaches. In particular, studies have suggested that the problem lies in or near the hypothalamus, a brain structure responsible for a wide range of automatic functions, including sleep, hunger, and body temperature. Scientists have found indications that people with cluster headaches may have both unusual electrical activity in the hypothalamus and atypical connections between the hypothalamus and other parts of the brain.

The hypothalamus regulates the body’s circadian rhythms, which control cyclical functions such as sleep patterns and changes in body temperature. This leads some scientists to think unusual hypothalamus activity might explain why some people experience cluster headaches seasonally or in other somewhat predictable, cyclical patterns.

Cluster Headaches Research

Title: Cluster Headache Treatment With Rimegepant

Stage: Recruiting 

Principal Investigator: Carrie Robertson, MD

Mayo Clinic

Rochester, MN

This is a prospective, open-label pilot study to investigate the use of rimegepant for the treatment of cluster headaches. Subjects will be screened at outpatient clinic visit appointments; interested qualified subjects will be consented and offered participation in this trial. Once consent has been obtained, patients with cluster headaches will start immediately keeping track of their headaches for a one-week baseline. In contrast, patients with episodic cluster headaches will be asked to contact the study coordinator at the onset of their next cluster cycle, at which point they will repeat the screening and then start their one-week baseline headache diary. After establishing the baseline headache frequency, severity, and abortive medicine use, patients will be asked to start their first dose of the study drug with their next moderate to severe cluster headache. They will rate their pain for this headache on a 5-point severity scale (“no headache,” “mild,” “moderate,” “severe,” or “very severe” and rate the pain on a scale of 0 to 10 (“0” is no pain and “10” is most severe pain imaginable) at the time of taking rimegepant and rate the pain again at 15, 30, 45, and 60 minutes after taking the drug. Finally, 60 or more minutes after taking the rimegepant, they are allowed to use their usual standard of care for the acute/abortive treatment of acute cluster attacks. After this first dose, they will then take rimegepant on an every-other-day schedule for a total of 4 doses over 8 days. A final visit for evaluation and collection of headache diaries will be conducted at the end of the study.


Title: High Dose Vitamin D Plus Multivitamin in the Prevention of Cluster Headache

Stage: Recruiting 

Principal Investigator: Mark J. Burish, MD, PhD

The University of Texas Health Science Center

Houston, TX

This study intends to investigate the use of high-dose Vitamin D3 plus a multivitamin to prevent cluster headache attacks.

Participants can be enrolled anywhere in the United States with access to one of our participating labs (for blood work – anticipated to be available in most of the USA).

The study may include:

  • Screening: Participants may be interviewed, examined, fill out surveys, and get blood testing
  • Week 1: baseline period (no added medications – to establish a baseline)
  • Weeks 2-4: double-blinded experimental period – participants receive either 1) high-dose Vitamin D3 + multivitamin, or 2) placebo + multivitamin. Participants also fill out a survey and have blood testing.
  • Weeks 5-7: open-label period – ALL participants receive high-dose Vitamin D3 + multivitamin. Participants also fill out a survey and may have blood testing.

Specifically, the primary outcome is the change from baseline to experimental weeks 1-3 in the frequency of cluster headache attacks between placebo and high-dose vitamin D. 


Title: The Will Erwin Headache Research Center – Cluster Headache Study (WEC1)

Stage: Recruiting 

Principal Investigator: Mark Burish, MD, PhD

The University of Texas Health Science Center

Houston, TX

The Will Erwin Headache Research Center will assemble a national registry of Cluster Headache patients and will sub-categorize and organize this cohort based on individuating characteristics including but not limited to type and severity of the condition, associated symptoms, and medical/psychological issues (e.g., depression, disability, sleep). Detailed evaluations and classification will be completed for each enrolled subject. This will encompass genomic and epigenomic studies, past medical history, imaging reports, and specific physical exam results for each patient. It will also enable the study investigators to match patients with suitable interventional clinical trials.

Similar diseases, such as other paroxysmal hemicrania, SUNCT, SUNA, hemicrania continua, and trigeminal neuralgia may also be investigated.

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