Cluster Headaches: What They Are, Why They Happen, and How They're Treated

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 14, 2026

Quick Answer

A cluster headache is severe, one-sided head pain lasting 15 minutes to 3 hours, occurring daily in clusters for weeks to months, then pausing for months or years [1] [2] [7]. Pain is often around one eye, with a watery eye and droopy eyelid [1] [6]. There is no cure, but preventive medications, attack treatments such as triptans or 100% oxygen, and other therapies help [1] [8].

What the research says

• Cluster headache is rare but intensely patterned. A clinical review reports it affects up to 0.1% of people, with attacks lasting 15 to 180 minutes up to 8 times a day, and a male-to-female ratio of about 2.5 to 1. (Wei et al., Annals of Indian Academy of Neurology, 2018) [7].

• High-flow oxygen stops many attacks within 15 minutes. In a randomized crossover trial of 109 adults, 78% of attacks treated with 100% oxygen were pain-free (or adequately relieved) at 15 minutes, compared with 20% of attacks treated with air. Oxygen was given at 12 L/min, data were analyzed for 57 people with episodic and 19 with chronic cluster headache, and there were no important adverse events. (Cohen et al., JAMA, 2009) [8].

• Galcanezumab modestly reduced attack frequency in episodic cluster headache. In a randomized trial of 106 patients (49 galcanezumab 300 mg, 57 placebo), weekly attacks fell by 8.7 versus 5.2 across weeks 1–3 (difference 3.5 attacks per week; 95% CI 0.2–6.7), and 71% versus 53% had at least a 50% reduction at week 3. Recruitment stopped before the planned 162 patients, so the trial was smaller than intended (Goadsby et al., N Engl J Med, 2019) [9].

• Acute treatments have stronger evidence than verapamil. A systematic review and meta-analysis of 27 randomized trials gave Level A advice for subcutaneous sumatriptan 6 mg, zolmitriptan nasal spray, and 100% oxygen at 6–12 L/min for attacks, but only Level C advice for verapamil 360 mg, lithium 900 mg, and melatonin 10 mg for prevention. This review dates from 2010 and newer trials such as galcanezumab are not included (Francis et al., Neurology, 2010) [10].

What Is a Cluster Headache?

A cluster headache is pain on one side of your head that lasts from 15 minutes up to three hours [1] [2] [7]. The pain occurs daily for weeks to months, often happening at the same time each day and up to eight times per day [1] [2] [7]. When you feel recurring cluster headache pain, it's called an attack. After an attack, you may go months or even years before you experience another cluster headache [1] [3].

They get their name from how they affect you. They come on in clusters, or groups, before temporarily going away for most people.

Cluster headaches are a type of primary headache — a headache that starts because of a response from the part of your brain that communicates pain, where the headache is its own health challenge, not part of a larger issue. This differs from secondary headaches, which start because of another health condition like ear infections, nasal congestion, or dehydration [1].

Cluster headaches aren't common. They affect an estimated 0.1% of people around the world — about 1 out of every 1,000 people [1] [4] [7].

Key Terms to Know

What Do Cluster Headaches Feel Like?

A cluster headache feels like a burning sensation, sharp pain, or stabbing pain [1] [6]. The symptoms happen on the same side of your head as the headache (unilateral).

Beyond the head pain itself, symptoms include a watery eye, eye redness, a droopy eyelid, a runny or stuffy nostril, and flushing or sweating [1] [6].

The pain location may vary but happens on only one side, in one of these regions:

Most people have pain on the same side of the head during an attack cycle. While rare, it may switch locations during another cycle. The most common location is around one eye to the side of your head at your hairline before your ear (the temple).

Many people report that cluster headaches wake them up an hour or two after going to bed [1]. They're sometimes called "alarm clock headaches" for this reason, and these nighttime headaches may feel more severe than those during the day.

When symptoms set in, it usually only takes five to 10 minutes for them to reach their worst [1] [6]. Some people report feeling restless during an attack — like they can't sit still and need to pace [1] [5].

You may experience slight discomfort or a burning feeling on one side of your head just before a cluster headache. But cluster headaches often come on fast, so these signs don't leave you much time to prepare.

How Long Do Cluster Headaches Last?

On average, a cluster headache tends to last 30 minutes [1]. You may experience up to eight of these headaches within 24 hours. Many people have daily cluster headache attacks that last for three months.

Then, the clusters usually pause, for reasons that aren't yet understood. The headaches go into remission (go away) for months or years before returning.

Some people never get much of a break, though. They experience chronic (ongoing) cluster headaches. This happens to about 1 in 5 people who get cluster headaches [1].

Cluster headaches are commonly seasonal. You might notice them in the fall and springtime the most [1].

What Causes Cluster Headaches?

Healthcare providers don't know the exact cause of cluster headaches [1] [6]. Research found that they could relate to your body releasing the following near the trigeminal nerve, the nerve that sends sensations between your face and brain:

• Histamine — a chemical that helps in allergic reaction response

• Serotonin — a chemical that carries messages between nerve cells

In addition, research found that cluster headaches may happen if there's dysfunction in the area of your brain called the hypothalamus. This part of your brain contains your "circadian clock," a built-in schedule that responds to sunlight. When seasons change, so does the amount of sunlight.

Research also found that cluster headaches can be genetic in up to 5% of people [1]. Studies are ongoing to learn more about the causes.

What Triggers Cluster Headaches?

A cluster headache trigger is something that causes your symptoms to start. Triggers during a cluster headache cycle vary from person to person but may include:

• Tobacco, alcohol and other substance use

• Bright lights

• Hot temperatures

• Nitrites in food (preserved meats)

• Certain medications (like sildenafil)

Triggers can also affect the start of a new cycle of attacks after a period of no symptoms. When headaches start, the shift may appear tied to changes in seasons — you might think you have allergies or sinusitis. This may happen because of suspected ties between cluster headaches and the hypothalamus and its circadian clock.

If you don't know what triggers your symptoms, talk to a healthcare provider and keep a journal to help you identify them. In your journal, you can write down:

• When and for how long you had a headache

• What foods or beverages you consumed the day before

• What activities you participated in before the headache

• How long and how well you slept the night before

• If you took any medications to treat the headache once it started and if it was effective

Who Is at Risk for Cluster Headaches?

You may be more at risk of cluster headaches if you are between age 20 and 40, drink alcohol frequently, take certain medications or use tobacco [1].

• Are between age 20 and 40

• Frequently drink alcohol

• Take certain medications

• Use tobacco products (cigarette smoking)

What Are the Complications of Cluster Headaches?

Cluster headaches can be an irritant that interferes with your daily routine, including your ability to complete personal obligations like work or school. You may not feel well enough to do the things you enjoy or even leave your home during an attack.

Having a severe headache every day can make you feel helpless like there's no hope. While rare, you may develop depression that can lead to suicidal thoughts [1]. Some people call cluster headaches "suicide headaches" for this reason.

If you experience suicidal thoughts, contact (call or text) the Suicide and Crisis Lifeline at 988 (U.S.). Someone is available to help 24/7.

How Are Cluster Headaches Diagnosed?

A healthcare provider (a neurologist) will diagnose a cluster headache after a physical exam. They'll want to know more about your symptoms and your medical history. A provider may offer an imaging test, like an MRI, to rule out conditions with similar symptoms [1] [6].

If you're experiencing attacks, it can help your provider learn more about your symptoms as they happen. Your provider might request an exam during the time when your headaches happen each day to observe how the headaches affect you.

How Are Cluster Headaches Treated?

Cluster headache treatment options may include medications to prevent headaches and medications to manage pain during an attack.

Prevention Medications

Certain medications can shorten a headache cycle. They can also make the headaches less severe. Common medications may include those that treat allergies, depression, blood pressure, and seizures [1] [6]. Also, galcanezumab is a U.S. Food and Drug Administration-approved preventive therapy, a monoclonal antibody that targets calcitonin gene-related peptide (CGRP) [1] [9].

Pain Management Medications (During an Attack)

When a headache occurs, certain medications may help with your symptoms, like:

• Triptan medicines (sumatriptan)

• Anti-inflammatory medicines (steroids like prednisone)

• Dihydroergotamine injections (can't be taken with sumatriptan)

Breathing in 100% oxygen may help relieve symptoms during an attack [1] [8].

Anti-inflammatory medications (NSAIDs like ibuprofen) aren't effective medications to treat cluster headaches [1].

Surgery

If medications don't help, your healthcare provider might suggest surgery. A surgeon may implant a neurostimulator device to send electrical signals to certain nerves in your head to manage your symptoms [1] [6]. Your provider will let you know if surgery is a good option.

Alternative Therapies

Some alternative therapies may provide relief from cluster headaches, including:

• Acupuncture — small needles inserted into your skin at various points to relieve pain

• Physiotherapy — treatment focused on stretching, moving joints, and massaging techniques

• Spinal manipulation — a chiropractic adjustment that realigns your spine

• gammaCore — an external vagus nerve stimulator (a portable, noninvasive neurostimulator)

What Is the Outlook for Cluster Headaches?

Cluster headaches don't affect your life expectancy and they're not life-threatening, but they can significantly impact how you feel each day [1] [6]. While cluster headaches are a chronic (long-term) condition, many studies found that these headaches become less frequent as you age [1] [7].

Can Cluster Headaches Be Cured?

Unfortunately, there is no cure for cluster headaches [1]. But you do have treatment options that can make them a little less painful or less frequent.

Your healthcare provider will work with you to develop an appropriate treatment plan. Make sure to follow your healthcare provider's recommendations for the most effective relief.

Can Cluster Headaches Be Prevented?

You can't prevent cluster headaches entirely. You can identify and avoid triggers that cause symptoms, like smoking or drinking alcohol, which reduces your risk of an attack [1] [6]. Triggers vary from person to person, so what you need to avoid may be different for someone else.

If you have sleep apnea that's related to your headaches, talk to a healthcare provider about managing that condition or any other underlying health conditions.

What reassurance is there for people with cluster headaches?

Everyone gets headaches from time to time for various reasons. But cluster headaches are no ordinary headaches — they're among the most painful headache types. The good news is that treatment is available to reduce the severity and how often these headaches occur. You're not alone, and healthcare providers can help.

If you suspect you have cluster headaches, reach out to a healthcare provider to confirm the diagnosis. You don't have to be in the midst of a cluster to see a specialist or get a diagnosis.

When Should You See a Healthcare Provider?

Contact a healthcare provider about cluster headaches if your headaches change in severity or frequency, don't resolve with medication or occur with a stiff neck or fever.

• Change in severity

• Are frequent or change in frequency

• Don't resolve with medication

• Occur with a stiff neck or fever

• Occur with speech, vision, or movement problems

Let your healthcare provider know if you become pregnant or are thinking about becoming pregnant and you're taking medications for headaches. Also let your provider know if you notice side effects or your medication doesn't feel effective anymore.

What is the bottom line on cluster headaches?

A cluster headache is severe, one-sided head pain that lasts 15 minutes to 3 hours and comes in groups [1] [7] — daily for weeks or months, often at the same time each day, up to eight times per day. It affects about 1 in 1,000 people [1] [4]. Symptoms peak within 5–10 minutes and often include a watery/red eye, droopy eyelid, runny or stuffy nostril, and restlessness; many attacks wake people from sleep ("alarm clock headaches"). The exact cause is unknown, but research links it to chemicals near the trigeminal nerve, hypothalamus dysfunction, and genetics in up to 5% of cases [1]. Cluster headaches aren't life-threatening, but they can seriously disrupt daily life — and rare cases of depression with suicidal thoughts are why they're sometimes called "suicide headaches." There's no cure, but prevention medications, attack treatments (triptans, steroids, dihydroergotamine, 100% oxygen), neurostimulator surgery, and alternative therapies can reduce how often and how painful they are [1]. If you suspect cluster headaches, see a healthcare provider — you don't need to be in the middle of a cluster to get diagnosed.

Frequently Asked Questions

What is a cluster headache?

A cluster headache is pain on one side of your head that lasts from 15 minutes up to three hours. The pain occurs daily for weeks to months, often at the same time each day and up to eight times per day, in groups called clusters.

Why are they called cluster headaches?

They get their name from how they affect you — they come on in clusters, or groups, before temporarily going away for most people.

How common are cluster headaches?

They aren't common. They affect an estimated 0.1% of people around the world — about 1 out of every 1,000 people.

Is a cluster headache a primary or secondary headache?

A cluster headache is a type of primary headache — it starts because of a response from the part of your brain that communicates pain, not because of another health condition.

What does a cluster headache feel like?

It feels like a burning sensation, sharp pain, or stabbing pain. Many people feel restless during an attack, like they can't sit still and need to pace.

What other symptoms come with a cluster headache?

Symptoms happen on the same side of your head as the headache (unilateral) and include a watery eye, eye redness, a droopy eyelid, a runny or stuffy nostril, and flushing or sweating.

Where exactly does the pain occur?

Pain happens on only one side, in the orbital region (behind your eye or near your temple), the supraorbital region (above your eye, near your forehead), or the temporal region (side of your head behind your ear). The most common location is around one eye to the temple at your hairline.

What are "alarm clock headaches"?

Many people report that cluster headaches wake them up an hour or two after going to bed. They're sometimes called alarm clock headaches for this reason, and nighttime attacks may feel more severe than daytime ones.

How quickly do symptoms peak?

When symptoms set in, it usually only takes five to 10 minutes for them to reach their worst.

Are there warning signs before a cluster headache?

You may experience slight discomfort or a burning feeling on one side of your head just before a cluster headache. But they often come on fast, so these signs don't leave you much time to prepare.

How long does an average cluster headache last?

On average, a cluster headache tends to last 30 minutes.

How many cluster headaches can I have in a day?

You may experience up to eight of these headaches within 24 hours.

How long does a cluster period last?

Many people have daily cluster headache attacks that last for three months. Then the clusters usually pause, and the headaches go into remission for months or years before returning.

What are chronic cluster headaches?

Some people never get much of a break — they experience chronic (ongoing) cluster headaches. This happens to about 1 in 5 people who get cluster headaches.

Are cluster headaches seasonal?

Yes, they're commonly seasonal. You might notice them in the fall and springtime the most.

What causes cluster headaches?

Healthcare providers don't know the exact cause. Research found they could relate to your body releasing histamine (a chemical that helps in allergic reaction response) and serotonin (a chemical that carries messages between nerve cells) near the trigeminal nerve. Dysfunction in the hypothalamus and genetics (in up to 5% of people) may also play a role.

What is the trigeminal nerve?

It's the nerve that sends sensations between your face and brain.

What is the hypothalamus?

It's the part of your brain that contains your "circadian clock" — a built-in schedule that responds to sunlight.

Can cluster headaches be genetic?

Yes. Research found that cluster headaches can be genetic in up to 5% of people. Studies are ongoing to learn more about the causes.

What triggers cluster headaches?

Triggers vary from person to person but may include tobacco, alcohol and other substance use, bright lights, hot temperatures, nitrites in food (preserved meats), and certain medications (like sildenafil).

Why do cluster headaches start when seasons change?

It may happen because of suspected ties between cluster headaches and the hypothalamus, which contains your circadian clock that responds to sunlight. When seasons change, so does the amount of sunlight.

How do I identify my triggers?

Talk to a healthcare provider and keep a journal. Write down when and how long you had a headache, what foods or beverages you consumed the day before, activities before the headache, how long and how well you slept, and whether medications taken were effective.

Who is at risk for cluster headaches?

You may be more at risk if you're between age 20 and 40, frequently drink alcohol, take certain medications, or use tobacco products (cigarette smoking).

Are cluster headaches dangerous or life-threatening?

No. Cluster headaches don't affect your life expectancy and they're not life-threatening, but they can significantly impact how you feel each day.

Why are they sometimes called "suicide headaches"?

Having a severe headache every day can make you feel helpless. While rare, you may develop depression that can lead to suicidal thoughts. If you experience suicidal thoughts, contact (call or text) the Suicide and Crisis Lifeline at 988 (U.S.) — someone is available to help 24/7.

How are cluster headaches diagnosed?

A healthcare provider (a neurologist) will diagnose a cluster headache after a physical exam, asking about your symptoms and medical history. An imaging test like an MRI may be offered to rule out conditions with similar symptoms. If you're experiencing attacks, your provider might request an exam during the time when your headaches happen each day.

What are the treatment options?

Treatment options may include medications to prevent headaches and medications to manage pain during an attack. If medications don't help, a surgeon may implant a neurostimulator device.

What prevention medications are used?

Common medications include those that treat allergies, depression, blood pressure, and seizures. Galcanezumab is an FDA-approved preventive therapy, a monoclonal antibody that targets calcitonin gene-related peptide (CGRP).

What medications help during an attack?

Triptan medicines (sumatriptan), anti-inflammatory medicines (steroids like prednisone), and dihydroergotamine injections (can't be taken with sumatriptan). Breathing in 100% oxygen may also help relieve symptoms during an attack.

Does ibuprofen work for cluster headaches?

No. Anti-inflammatory medications (NSAIDs like ibuprofen) aren't effective medications to treat cluster headaches.

What is a neurostimulator device?

If medications don't help, your provider might suggest surgery to implant a neurostimulator device, which sends electrical signals to certain nerves in your head to manage your symptoms.

What alternative therapies may help?

Acupuncture, physiotherapy (stretching, moving joints, massage), spinal manipulation (chiropractic adjustment), and gammaCore — an external vagus nerve stimulator that is a portable, noninvasive neurostimulator.

Is there a cure for cluster headaches?

Unfortunately, there is no cure for cluster headaches. But treatment options can make them a little less painful or less frequent.

Can cluster headaches be prevented?

You can't prevent them entirely, but you can identify and avoid triggers that cause symptoms, like smoking or drinking alcohol, which reduces your risk of an attack. Triggers vary from person to person.

Does sleep apnea affect cluster headaches?

If you have sleep apnea that's related to your headaches, talk to a healthcare provider about managing that condition or any other underlying health conditions.

When should I see a healthcare provider?

Contact a provider if headaches change in severity, become frequent or change in frequency, don't resolve with medication, occur with a stiff neck or fever, or occur with speech, vision, or movement problems.

Do I need to be having an attack to get diagnosed?

No. You don't have to be in the midst of a cluster to see a specialist or get a diagnosis.

Should I tell my provider if I'm pregnant or planning pregnancy?

Yes. Let your healthcare provider know if you become pregnant or are thinking about becoming pregnant and you're taking medications for headaches.

What happens if my medication stops working?

If you notice side effects or your medication doesn't feel effective anymore, let your provider know.

What questions should I ask my healthcare provider?

Consider asking: What triggers my symptoms? Do I need to keep a journal to identify triggers? What type of treatment do you recommend? Are there side effects of treatment? Can you recommend any alternative therapies? When and how often should I take medication to treat an attack? Are there any herbal supplements or over-the-counter medications I can take?

What is the long-term outlook?

Cluster headaches don't affect your life expectancy. While they're a chronic (long-term) condition, many studies found that these headaches become less frequent as you age.

Related Reading

• Migraine Headaches: What Causes Them and How to Treat Them

• Tension Headache: Why the Most Common Head Pain Feels Like a Tight Band, and What Actually Helps

• Sinus Headache Guide: Symptoms, Causes, Diagnosis, and Treatment

References

1. Cleveland Clinic. Cluster Headaches. Cleveland Clinic. Last updated December 22, 2023. https://my.clevelandclinic.org/health/diseases/5003-cluster-headaches

2. Weaver-Agostoni J. Cluster headache. Am Fam Physician. 2013;88(2):122-128. PMID 23939643. https://pubmed.ncbi.nlm.nih.gov/23939643/

3. American Migraine Foundation. Understanding Cluster Headache. American Migraine Foundation. Last updated April 8, 2019. https://americanmigrainefoundation.org/resource-library/cluster-headache-2/

4. Kandel SA, Mandiga P. Cluster Headache. StatPearls (NCBI Bookshelf). Last update July 4, 2023. PMID 31334961. https://www.ncbi.nlm.nih.gov/books/NBK544241/

5. Merck Manual. Cluster Headaches. Merck Manual Consumer Version. Last updated February 2025. https://www.merckmanuals.com/home/brain-spinal-cord-and-nerve-disorders/headaches/cluster-headaches

6. National Library of Medicine. Cluster headache. MedlinePlus Medical Encyclopedia. Review date October 27, 2025. https://medlineplus.gov/ency/article/000786.htm

7. Wei DY, Yuan Ong JJ, Goadsby PJ. Cluster Headache: Epidemiology, Pathophysiology, Clinical Features, and Diagnosis. Ann Indian Acad Neurol. 2018;21(Suppl 1):S3-S8. PMID 29720812. https://doi.org/10.4103/aian.AIAN_349_17

8. Cohen AS, Burns B, Goadsby PJ. High-flow oxygen for treatment of cluster headache: a randomized trial. JAMA. 2009;302(22):2451-2457. PMID 19996400. https://doi.org/10.1001/jama.2009.1855

9. Goadsby PJ, Dodick DW, Leone M, et al. Trial of galcanezumab in prevention of episodic cluster headache. N Engl J Med. 2019;381(2):132-141. PMID 31291515. https://doi.org/10.1056/NEJMoa1813440

10. Francis GJ, Becker WJ, Pringsheim TM. Acute and preventive pharmacologic treatment of cluster headache. Neurology. 2010;75(5):463-473. PMID 20679639. https://doi.org/10.1212/WNL.0b013e3181eb58c8

Medical disclaimer

This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. If you are experiencing suicidal thoughts or a mental health emergency, call or text the Suicide and Crisis Lifeline at 988 (U.S.) or contact emergency services immediately. Never disregard professional medical advice or delay seeking it because of something you have read here. Individual treatment decisions should always be made with your healthcare team.