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Cluster Headaches

Cluster Headaches Overview

Cluster headaches are named for the cyclical patterns, or clusters, in which they occur. It is one of the primary headache disorders, which means that it is not known to be caused by a different underlying disease or condition. Cluster headaches arise suddenly, producing attacks of severe pain on one side of the head. The pain is often focused behind or around the eye and lasts from 30 minutes to three hours.

Cluster headache periods, also called bouts, can last several weeks or months and be followed by pain-free periods that last months or years. Attacks often occur around the same time each day. These headaches tend to be severe or very severe in intensity. The frequency of the attacks varies from person to person, though it can range from one headache every other day to eight or more headaches in a single day. Along with the severe headache, patients tend to experience cranial autonomic symptoms on the same side of the headache, which is typically unilateral, or only affecting one side of the head or face. 

Whereas most people with cluster headache experience the episodic form, characterized by weeks-long periods of cluster headache followed by weeks-to-months-long periods without headaches, approximately 20% of people experience a more chronic form. The chronic form is characterized by headaches that occur for a year or more with pain-free periods of only a month or less.

Symptoms of Cluster Headaches

Pain associated with cluster headaches usually has the following characteristics:

  • Severe to very severe
  • Unilateral (affecting only one side of the head or face)
  • Often focused behind or around one eye
  • Peaks within 5-10 minutes of onset and continues at that intensity for 30 minutes to three hours
  • Often begin at night, while sleeping

Headache pain may be accompanied by the following autonomic symptoms on the side of the face where the pain is felt:

  • Swollen or drooping eyelid
  • Congested or runny nose
  • Redness of the eye
  • Excessive watering of the eye
  • Abnormally small pupil size
  • Forehead and facial sweating
  • Red, flushed face
  • Ear fullness or pressure
  • Restlessness (this symptom can occur in the absence of any of the above listed cranial autonomic features)

Cluster Headaches Treatments

Like other primary headache disorders, cluster headaches are typically managed and treated with a combination of preventive and acute medications or therapies. The most commonly used preventive medication for the treatment of cluster headache is verapamil, which is a calcium channel blocker. Verapamil is frequently used for the treatment of high blood pressure, but it is often effective in decreasing the intensity, duration, and/or the number of cluster headaches experienced by the patient. It can be helpful in both episodic and chronic cluster headache.

Other preventive medications that have shown to be effective in the treatment of cluster headache include:

More recently, galcanezumab (Emgality) has gained FDA approval for the treatment of cluster headache. Emgality is also used for the prevention of migraine headache, though the dose in cluster headache treatment is higher—300 mg monthly for cluster headache versus 120 mg monthly for migraine. 

For patients with episodic cluster headache, it is often advisable to taper off from the preventive treatment until the next cluster attack period begins to help reduce the risk of medication side effects. 

Acute symptomatic treatment of cluster headache is meant to stop a cluster headache quickly once it begins. Triptans are a class of medications commonly used to provide fast relief for migraine and cluster headache pain. Specifically, the drug sumatriptan (Imitrex) may be given as an injection. 

Nasal spray triptan medications such as sumatriptan and zolmitriptan (Zomig) also can be beneficial. These medications are available in pill form, but these are less likely to be effective compared to the injectable and intranasal formulations. 

Other medications used to treat cluster headaches can include:

Inhaling pure oxygen can provide substantial relief. However, some patients find oxygen canisters too bulky and inconvenient to have ready when a cluster headache strikes.

Identifying and avoiding your triggers can help prevent cluster headaches. Documenting the following in a headache diary can help you identify your triggers:

  • Day and time the pain began
  • What you ate and drank in the previous 24 hours
  • How much you slept
  • What you were doing when the pain began
  • How long the pain lasted
  • What made the pain stop


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Additional Information

How common are cluster headaches?

Cluster headaches are relatively uncommon, affecting fewer than 1 in 1,000 adults.

Who gets cluster headaches?

Cluster headaches are more common in men than in women and in smokers than nonsmokers. The age of onset is typically between 20 and 30 years, but cluster headaches can begin at any age.

How are cluster headaches diagnosed?

Your doctor may use the following to diagnose cluster headaches:

  • Personal and family medical history
  • Physical and neurological examinations
  • Imaging to rule out other causes of headache

Additional Resources

American Migraine Foundation
World Health Organization
National Institute of Neurological Disorders and Stroke
National Headache Foundation
National Institutes of Health

Group 49
  in 1,000 Adults
Cluster headaches are relatively uncommon, affecting fewer than 1 in 1,000 adults.
Medically Reviewed by Kerry Knievel, DO, FAHS on September 4, 2022