Disorders

What is cluster headache?

Reviewed July 2026 by Olivia Begasse de Dhaem, MD, FAHS

Definition: Cluster headache is a rare headache disorder that causes repeated attacks of severe one-sided head pain, usually around or behind one eye or at the temple. Attacks often come with symptoms on the same side of the face or eye, such as tears, redness, eyelid swelling, or a runny or stuffy nose. They often happen in “clusters,” with active periods that last weeks to months.

Cluster headache has two main patterns:

  • Most people have episodic cluster headache, which means attacks come in active periods lasting from a week to a year (often 4–12 weeks). These are followed by headache-free periods of at least three months.
  • The less common pattern is called chronic cluster headache. These attacks happen for at least a year with headache-free periods shorter than three months, if any.

During an active period, attacks usually happen from once every other day to eight times per day. Cluster headache can have a major effect on daily life, and getting a diagnosis can take time. Recognizing the pattern of attacks is an important step toward finding care that can help.

What are the symptoms of cluster headache?

Common symptoms and features can include:

  • Severe or very severe pain on one side of the head, usually around the eye, above the eye, or at the temple.
  • Pain that may spread to the forehead, jaw, throat, ear, neck, or shoulder.
  • Attacks that usually last 15 to 180 minutes if untreated.
  • Eye and face symptoms on the painful side, such as tears, red eye, runny or stuffy nose, eyelid swelling, forehead or facial sweating, a smaller pupil, or a drooping eyelid.
  • A strong feeling of restlessness or agitation during an attack; many people pace or rock rather than lie still.

Some people with cluster headaches also experience “shadows,” which are dull, aching, or pressure-like feelings in the usual area of pain before an attack. Less commonly, they can happen after an attack.

Cluster headache attacks tend to peak during the spring and fall, a pattern that could be caused by seasonal changes in daylight. Many attacks happen at night, and sleep is a trigger for many people during an active period.

What are the causes and risk factors of cluster headache?

The exact cause of cluster headache is not fully understood. It’s considered a primary headache disorder, which means it’s not usually caused by another medical problem.

Cluster headache is more common in men than in women, and genes may play a role for some people.

During an active period, some triggers can bring on attacks, including alcohol, nitroglycerin (an artery medication), or histamine (a chemical released by your immune system). Smoking cigarettes can trigger or worsen cluster attacks.

During headache-free periods, your usual triggers may have no effect.

How is cluster headache diagnosed?

Cluster headache is diagnosed mainly by looking closely at a person’s symptoms and completing a neurological exam. No single lab test, scan, or other test can confirm cluster headache on its own.

If your symptoms are new or include other neurological signs, your doctor (usually a neurologist) may recommend an MRI. This can help rule out rare causes of similar headaches. Blood tests, spinal fluid tests, and other studies are not usually helpful for diagnosing cluster headache unless your doctor thinks you might have a different condition.

Since cluster headache is rare, your doctor will also consider migraine and other headache-causing conditions.

What treatments are available for cluster headache?

Treatment usually includes both attack treatment, which aims to stop an individual attack, and preventive treatment, which aims to reduce how often attacks happen. Because attacks can start quickly and become severe, it’s important to have a plan for what to do when symptoms start.

Cluster headache treatment often needs careful monitoring, so care should be guided by a neurologist or other health care professional who understands headache disorders.

The main acute treatments for cluster attacks include:

  • Oxygen therapy: Breathing in 100% high-flow oxygen through a non-rebreather mask
  • Subcutaneous sumatriptan: A fast-acting self-injected medication
  • Noninvasive vagus nerve stimulation (VNS): A device that delivers mild electrical pulses to the neck, for episodic cluster headache only

Many patients find energy drinks that contain taurine helpful.

The main preventive treatments for cluster attacks include:

  • Verapamil, which is usually the first preventive medicine for both episodic and chronic cluster headache.
  • Galcanezumab, which is approved for episodic cluster headache.
  • Lithium is sometimes the second choice if verapamil isn’t working. Your doctor will need to monitor your blood levels and kidney, thyroid, and heart function.

Some people may need a combination of preventive treatments. Nerve blocks and corticosteroids can be used as a bridge to provide further help at the start of a cluster period while the preventive treatment kicks in.

Cluster headache is one of the most intensely painful conditions ever, and it can be very isolating. Attacks have a significant impact on every aspect of people’s lives. Learning more about the condition and joining support organizations can help you feel less alone, making these steps an important part of treatment.

Working through diagnosis and treatment options for cluster headache

It can take a long time to be diagnosed with cluster headache. If you think you or a loved one might have cluster attacks, talk to your primary care provider and establish care with a neurologist.

Some people need to see several healthcare providers before they get the right diagnosis and treatment—it’s worth looking for another provider until you get the care you need. Keep a careful record of when attacks happen, how long they last, which side is affected, and other symptoms to help your doctor evaluate the pattern.

Because attacks are short and severe, quick-acting treatments and a prevention plan are important. Ask your doctor what to do when an attack starts, what treatment to keep available, what triggers to avoid, and when to adjust your prevention plan.

If your symptoms are new, change suddenly, or happen with other neurological problems, talk to your doctor quickly. Cluster-like headaches can sometimes have another cause, and checking early can help you get the right care.

Frequently asked questions

How are cluster attacks different from migraine attacks?

Cluster attacks are usually shorter than migraine attacks, but they can happen many times in one day and often come in bouts over weeks to months. Cluster attacks are one-sided, often centered around the eye, and commonly cause tears, a runny or stuffy nose, or eyelid changes on the painful side. People also tend to feel restless and want to move.

Migraine attacks last longer, and people prefer to stay still. Sleep tends to help with migraine attacks.

It’s possible to have both conditions.

What does a cluster headache feel like?

People often describe the pain as a stabbing, burning, or “hot knife” pain around one eye or temple. The pain is usually very severe and may come with tears, a red eye, a stuffy or runny nose, eyelid swelling, or a drooping eyelid on the same side. Many people feel so restless during an attack that they pace or rock.

How long do cluster headaches last?

A single untreated attack usually lasts 15 to 180 minutes. During a cluster period, attacks may happen as often as eight times a day.

In episodic cluster headache, the active period can last from a week to a year, followed by headache-free periods of at least 3 months. In chronic cluster headache, headache-free periods are shorter than 3 months over at least a year.

Who gets cluster headache?

Cluster headache is rare, affecting about 0.1% to 0.2% of the population. It’s more common in men than in women, and most people have the episodic form rather than the chronic form. Children can also have cluster headache.

Some families have more than one person with cluster headache, which suggests that genetics may play a role for some people.