Cluster Headache: The Most Painful Condition You’ve Never Heard Of

Defining Features of Cluster Headache

Cluster headache is a primary headache disorder belonging to a group called the Trigeminal Autonomic Cephalalgias (TACs). This name perfectly describes their nature: pain (-algia) in the head (ceph-) involving the trigeminal nerve and accompanied by autonomic (involuntary) symptoms on the same side of the head.

Episodic vs. Chronic Cluster Headache

The distinction between the two main forms of cluster headache is based entirely on the timing and duration of the pain-free remission periods.

What’s the Difference?

The International Classification of Headache Disorders (ICHD-3) provides precise definitions ²:

• Episodic Cluster Headache (ECH): This is the more common form, affecting approximately 80-90% of patients. It is defined by cluster periods (bouts) lasting from 7 days to 1 year, which are separated by pain-free remission periods lasting three months or longer.
• Chronic Cluster Headache (CCH): This less common but more relentless form affects 10-20% of patients. It is defined by attacks occurring for more than one year without any remission period, or with remission periods that last less than three months.

Definitions: Episodic means attacks come and go in cycles. Chronic means attacks are nearly constant.

Impact of Chronification

The attacks themselves—their duration, intensity, and associated symptoms—are identical in both episodic and chronic forms. The critical difference is the absence of sustained relief for those with the chronic form. Living with the daily reality or threat of an excruciating attack, without the hope of a long remission period, places an extraordinary burden on mental health, relationships, and the ability to work or plan for the future. It is possible, though not guaranteed, for the disorder to transform from episodic to chronic, or vice versa, over a person’s lifetime. The mechanisms behind this transformation are a key area of ongoing research.

Sudden, Severe, One-Sided Pain

The hallmark of a cluster headache is its pain. It is almost always unilateral (affecting only one side of the head) and is locked to that side for the duration of a cluster bout. The onset is rapid, with the pain escalating from nothing to maximum, excruciating intensity usually within minutes. The most common descriptors of the are a sharp, piercing, boring, or burning sensation, often feeling like a hot poker is being driven into the eye or temple ². The pain is located in the orbital (eye), supraorbital (above the eye), or temporal (temple) region, or any combination of these.

Short Duration but High Frequency of Attacks

While the pain is severe, individual attacks are shorter when compared to a migraine attack. A single, untreated cluster headache attack lasts between 15 and 180 minutes ². During an active cluster period, a person can experience these attacks anywhere from once every other day to as many as eight times in a 24-hour period. This relentless repetition of severe pain, night after night, contributes to the disability of the disease.

The Cyclical Pattern: Clusters and Remissions

Cluster headache is also unique amongst headache disorders by the pattern it can form. This includes:

• The cyclical nature of the attacks (‘clusters’ of attacks)
• The timing of the attacks through the day
• The timing of the clusters in the year

The name “cluster headache” comes from its most defining feature: its cyclical nature. In episodic cluster headache, the attacks occur in these active periods, known as cluster bouts or periods, which can last for weeks or, more commonly, months. These bouts are then, for most patients, followed by pain-free periods called remission. A remission is a symptom-free period that can last for months or even years.

In episodic cluster headache, an acute ‘attack’ in cluster headache is much more likely to occur between 2200 and 0200, disrupting sleep – a pattern not seen in migraine and other common primary headache disorders. It is also more common to experience a cluster at certain times in the year (springtime is the most common time).

Symptoms of a Cluster Headache Attack

The excruciating pain is only part of the story. A defining feature of cluster headache is the set of accompanying symptoms that occur on the same side as the pain. These can be summarised as the three “A’s”

• Anterior, side locked pain
• Autonomic symptoms on the same side of the pain
• Agitation or restless during an attack

Anterior Intense Piercing or Burning Pain

As detailed above, the pain is the central feature. Its severity is ranked 10/10 on the pain scale by most patients, and its character is distinct from the throbbing pain often associated with migraine.

Side-Locked Pain

For the vast majority of patients, the pain is strictly side-locked, meaning it attacks the same side of the head during a single cluster bout and often for the patient’s entire life. However, a small minority of patients (around 15-20%) may experience a “side-shift” between different cluster periods, and even more rarely, the side can alternate during the same bout ¹³.

Autonomic Cranial Symptoms

To receive a formal diagnosis, a patient must experience at least one of the following symptoms on the same side as the head pain ²:

• Conjunctival injection and/or lacrimation: A bloodshot or red eye, and/or excessive tearing from that eye.
• Nasal congestion and/or rhinorrhoea: A blocked or stuffy nostril, and/or a profusely runny nose.
• Eyelid oedema: Swelling of the eyelid.
• Forehead and facial sweating: Noticeable sweating on the forehead or face.
• Miosis and/or ptosis: Miosis (constriction of the pupil) and/or ptosis (a visible drooping of the upper eyelid).
• A sense of fullness in the ear.

Definition: Autonomic symptoms are automatic body reactions like a red eye, tearing, or a stuffy nose.

Agitation or restlessness: A Key Diagnostic Clue

A profound sense of restlessness or physical agitation is a common symptom during an attack. Unlike a person experiencing a migraine attack, who typically seeks to lie still in a dark, quiet room, a person in the throes of a cluster attack is often unable to keep still. They may pace the floor relentlessly, rock back and forth, or even bang their head against a wall in a desperate attempt to create a distracting, counter-irritant pain. This behaviour is so characteristic that it is included as a core diagnostic criterion ².

Cluster Headache

Part of the delay in cluster headache stems from its confusion with other health disorders, which can lead to confusion, unnecessary investigations and ineffective treatment. Understanding their fundamental differences is crucial for patients, families, and healthcare providers.

The common culprit: migraine

Migraine is the second most common primary headache disorder, making it one of the leading causes of years lived with disability worldwide. While it does share some symptoms with cluster headache, there are key differences that can help your doctor differentiate between these conditions. For a deeper dive into migraine, you can visit our page on understanding migraine.

The table below summarises the ‘typical features’, or most commonly described presentation. It is not uncommon to not meet every aspect of either cluster headache or migraine when you live with the disease – if you have any concerns about an atypical symptom, discuss this with your treating doctor, and why they feel you have one condition or the other. As an example, while sensitivity to light is discussed as a ‘migraine’ symptom, many people living with cluster headache will notice this on their affected side during an attack, and conversely, cranial autonomic symptoms can occur in migraine!

Comparison Table: Cluster Headache vs. Migraine

Other possible mimics

While cluster headache has a characteristic pattern that can facilitate early recognition and diagnosis, not every ‘side-locked’ headache is indeed cluster headache. In fact, in a study of all patients attending an expert centre, only 20% of all ‘side-locked’ pain was cluster headache. The critical step is working with your doctor, and if there is any concern a neurologist or other appropriate specialist to find the cause of your pain. Other causes of side-locked headaches in the study included:

• Migraine (it can happen!)
• Other trigeminal autonomic cephalgias such as hemicrania continua and SUNCT (differentiated on the duration of the attacks)
• Cervicogenic headache
• Trigeminal neuralgia or neuropathy
• Other disorders such as dental disorders, TMJ disorders, optic neuritis, glaucoma, dissection

At this point, it may seem that the presence of a ‘side-locked’ headache is cluster headache,

Why Misdiagnosis Is So Common

It can be challenging! As discussed, the prevalence of cluster headache has been a barrier to its recognition, however a persons presentation may differ from the textbook, and people may not have the “lay down misère” of all the symptoms of one condition and none of another. For this reason it is possible to miss the diagnosis of cluster headache, or conversely miss a mimic of cluster headache. A thorough clinical history is key to differentiating between headache disorders – keeping a diary of your symptoms, what has (and has not!) worked in the past, and discussing your concerns with your doctor are all powerful things that can help reach the diagnosis.

Triggers and Timing: The Brain’s Internal Clock

The Role of Circadian Rhythms and the Hypothalamus

Many patients report that their attacks strike with clockwork regularity, often occurring at the same time each night. The most common time for an attack is about 1-2 hours after falling asleep, coinciding with the first REM sleep stage. This striking circadian rhythmicity (adherence to a 24-hour cycle) points directly to a specific area of the brain: the hypothalamus. Often called the body’s “master clock,” the hypothalamus regulates our sleep-wake cycles, hormone release, and other daily rhythms. Functional brain imaging studies (fMRI and PET scans) have provided definitive evidence, showing that the posterior hypothalamus becomes activated specifically during a cluster attack, but not in the pain-free periods between attacks ³. This finding was a landmark in headache science, cementing cluster headache’s identity as a primary brain disorder rooted in the hypothalamus.

Explanation: The hypothalamus is the brain’s master regulator. Amongst its functions include controlling daily rhythms like your sleep cycle.

Known Attack Triggers

It is important to distinguish between the underlying cause of a cluster bout (which is the hypothalamic activation) and the specific triggers that can set off an individual attack once a bout has already started. During an active cluster period, people living with cluster headache may notice the following triggers:

• Alcohol: This is the most notorious trigger. Even a small amount of an alcoholic beverage can provoke a classic cluster attack, typically within 30 to 60 minutes. Interestingly, this sensitivity usually disappears completely during remission periods.
• Nitroglycerin: This potent vasodilator (a substance that widens blood vessels) is a known experimental trigger used in research settings.
• Strong Smells: Some patients report that strong odours from volatile substances like perfume, gasoline, paint fumes, or cleaning solvents can trigger an attack.
• Overheating: Sudden changes in body temperature, such as from a hot shower or strenuous exercise, can also act as a trigger for some individuals during a bout.

It is a common misconception that stress causes cluster headache. While the stress of living with the condition is immense, cluster headache is a biological disorder of the brain, not a psychological one.

How Cluster Headache Is Diagnosed

An accurate diagnosis is the first and most critical step toward effective management. Unfortunately, due to its rarity, the path to diagnosis is often long and frustrating.

The Gold Standard: Clinical Criteria (ICHD-3)

There is no blood test or single brain scan that can definitively diagnose cluster headache. The diagnosis is made clinically, which means it is based entirely on the patient’s detailed history and a neurological examination. The global standard for diagnosis is the International Classification of Headache Disorders, 3rd edition (ICHD-3), published by the International Headache Society ².

To be diagnosed with cluster headache, a patient must meet the following criteria:

1. At least five attacks fulfilling criteria B–D.
2. Severe or very severe unilateral orbital, supraorbital and/or temporal pain lasting 15–180 minutes (when untreated).
3. Either or both of the following:
   1. At least one of the following symptoms or signs, ipsilateral (on the same side as the pain):
      • Conjunctival injection and/or lacrimation (red/watery eye)
      • Nasal congestion and/or rhinorrhoea (stuffy/runny nose)
      • Eyelid oedema (swollen eyelid)
      • Forehead and facial sweating
      • Miosis and/or ptosis (constricted pupil/drooping eyelid)
   2. A sense of restlessness or agitation.
4. Attacks have a frequency between one every other day and eight per day for more than half of the time when the disorder is active.
5. Not better accounted for by another ICHD-3 diagnosis.

The Importance of Patient History and a Headache Diary

Because the diagnosis relies on your story, your description of the attacks is the most important diagnostic tool. Keeping a detailed headache diary is invaluable. You can use a notebook or a dedicated app (like Migraine Buddy) to track:

• Date and time of each attack
• Duration of the attack
• Pain severity (on a 1-10 scale)
• Specific symptoms experienced (e.g., tearing, restlessness)
• Any potential triggers
• What treatment you used and whether it worked

Presenting this data to your doctor can dramatically speed up the diagnostic process and help differentiate cluster headache from other disorders.

The Role of Imaging

While a brain scan (typically an MRI) cannot confirm a diagnosis of cluster headache, it is an essential part of the diagnostic workup. Its purpose is to rule out any underlying structural problems in the brain or pituitary gland that could, in rare cases, mimic the symptoms of a TAC.

Treatment Options: A Modern Toolkit

Treating cluster headache requires a two-pronged approach: acute (or abortive) treatments to stop an attack that is already happening, and preventive (or prophylactic) treatments to stop the attacks from occurring in the first place during a bout.

While there are multiple treatment options, not all therapies are effective for everyone, or safe in every health condition. Work with your doctor to find the most appropriate and effective treatment for you.

Acute (Abortive) Treatments: Stopping an Attack in its Tracks

Because the attacks in cluster headache are short but severe, the treatment must work within minutes, and so the goal of therapy is rapid pain relief.

High-Flow Oxygen Inhalation: This is a cornerstone of acute treatment and is considered a first-line therapy. It involves inhaling 100% oxygen through a non-rebreather face mask at a high flow rate. Evidence-based guidelines and clinical trials support a range of flow rates, typically between 7 and 15 litres per minute (L/min) for 15-20 minutes ⁷. In Australia, prescribing guidelines often cite 7-12 L/min, but many headache specialists advocate for the higher rate of 12-15 L/min for maximum efficacy ⁵. The oxygen is thought to work by causing vasoconstriction (narrowing) of cerebral blood vessels and modulating nerve activity in the trigeminal ganglion. For information on accessing this therapy, see Headache Australia’s guide to oxygen therapy for cluster headache.

Triptans: This class of drugs is also a first-line acute treatment. However, oral tablets are often less effective because they are absorbed slower then non-oral formulations. Non-oral forms of triptans include:

• Subcutaneous Sumatriptan: A self-administered injection of sumatriptan is highly effective, often providing relief within 10-15 minutes ⁸. This is a key tool for most patients. Unfortunately within Australia, this is not PBS listed, and can be expensive.
• Intranasal Triptans: Sumatriptan and zolmitriptan are available as nasal sprays. While faster than tablets, they are generally slightly slower and may be less effective than the injection. In Australia, these nasal sprays are TGA-approved for migraine, so their use for cluster headache is considered “off-label” but is well-supported by international guidelines and common practice ⁵. At the time of writing, access to intranasal sumatriptan is more limited due to varying supply arrangements and it is important to discuss this with your doctor, and possible alternative options.

Preventive (Prophylactic) Treatments: Breaking the Cycle

The goal of preventive therapy is to reduce the frequency and severity of attacks during a cluster bout, or to end the bout altogether.

• Verapamil: This calcium channel blocker is the undisputed first-line preventive medication for both episodic and chronic cluster headache ⁵. It is typically started at a low dose and gradually increased. A critical safety requirement is that patients must have regular electrocardiogram (ECG) monitoring before starting and during dose escalation to monitor for potential cardiac side effects, specifically heart block.
• Lithium: Often used as a mood stabiliser, lithium can also be an effective preventive for cluster headache, particularly in the chronic form. It also requires careful monitoring of blood levels to ensure safety and efficacy.
• CGRP Monoclonal Antibodies: This newer class of medication has revolutionised migraine prevention. One of these drugs, galcanezumab (Emgality), has also been approved for the treatment of episodic cluster headache in the US and Europe. In Australia, the situation is different: galcanezumab is approved by the Therapeutic Goods Administration (TGA) and subsidised by the Pharmaceutical Benefits Scheme (PBS) for chronic migraine only ^{11, 12}. Therefore, its use for cluster headache in Australia is “off-label” and is not PBS-subsidised, making access difficult due to high out-of-pocket costs.
• Transitional Prophylaxis: Sometimes, a short course of corticosteroids (like prednisone) or a greater occipital nerve (GON) block may be used to quickly break a cycle while a long-term preventive like verapamil is taking effect.

Neuromodulation and Advanced Interventions

For patients with medically refractory chronic cluster headache (meaning they have failed multiple preventive medications), more advanced options may be considered.

• Non-invasive Vagus Nerve Stimulation (nVNS): This involves a handheld device (gammaCore) that is placed on the neck to deliver a mild electrical stimulation to the vagus nerve. Robust clinical trials have shown it to be effective for both the acute treatment of attacks in episodic CH and as a preventive therapy to reduce attack frequency in chronic CH ^{9, 10}.
• Invasive Procedures: For the most severe and intractable cases, surgical options may be explored at highly specialised centres. These can include Occipital Nerve Stimulation (ONS), Sphenopalatine Ganglion (SPG) Stimulation, or, in rare cases, Deep Brain Stimulation (DBS) of the hypothalamus.

What Doesn’t Work: Why Typical Painkillers Fail

It is critical to understand that standard over-the-counter painkillers like paracetamol and ibuprofen, as well as oral opioid medications, are not effective for treating an acute cluster headache attack. The reason is simple pharmacokinetics: the pain of a cluster attack escalates to its peak in minutes and the attack itself may be over in 15-30 minutes. Oral medications take far too long to be absorbed into the bloodstream and take effect, long after the attack has run its course. They do not target the specific neurological pathways involved.

Treatment Considerations for Children and Adolescents

While cluster headache typically begins in adulthood (20s-40s), it can, in rare cases, affect adolescents and even young children. Diagnosing and treating this population requires special considerations.

Diagnosis: The presentation in adolescents is usually similar to adults. In younger children, however, they may be less able to articulate the specific quality and location of the pain. The restlessness and agitation can sometimes be misinterpreted as a behavioural issue. A high index of suspicion and a very careful history taken from both the child and parents are key.

Treatment: Management should always be handled by a paediatric neurologist or a headache specialist with experience in this age group.

• Acute Treatment: High-flow oxygen is considered safe and is the preferred first-line acute treatment for children and adolescents. Triptans can be used, but with caution. Nasal sprays are often preferred over injections, and doses are carefully adjusted for age and weight.
• Preventive Treatment: Verapamil can be used, but the requirement for very careful and frequent ECG monitoring is even more critical in younger patients. Other options like topiramate or sodium valproate may be considered, always weighing the potential benefits against the risks.

Living with Cluster Headache

The impact of this condition extends far beyond the minutes of physical pain. The cyclical, unpredictable nature of the disorder casts a long shadow over every aspect of a person’s life.

The Emotional Toll and Mental Health Impacts

Living in a state of constant dread, waiting for the next inevitable, excruciating attack, takes a massive psychological toll. The sleep deprivation from nocturnal attacks exacerbates this. Rates of anxiety and depression are significantly higher in people with cluster headache than in the general population. As mentioned, the profound severity of the pain leads to a high rate of suicidal ideation, highlighting the desperate need for effective treatment and strong psychological support ⁴.

Impact on Sleep, Work, and Daily Life

The common timing of attacks at night leads to chronic sleep disruption, which has cascading effects on mood, cognitive function, and overall health. The ability to hold down a job can be severely compromised. The need to avoid triggers like a social drink can lead to social isolation. Relationships can be strained as loved ones watch helplessly. The period between attacks, even during remission, is often not truly pain-free; it is filled with the fear and anticipation of the cycle’s return. This “inter-attack burden” is a major contributor to the condition’s disabling nature. Migraine & Headache Australia is dedicated to providing resources and advocating for policies that support patients in the workplace and community.

How You Can Help Someone During an Attack

• Stay Calm. Your calm presence is more helpful than a panicked one.
• Act Fast. The person needs their acute treatment immediately. Help them get their oxygen mask on or prepare their sumatriptan injection if they need assistance.
• Give Them Space. Do not try to hold them down or force them to lie still. Their need to pace or rock is a core part of the attack. Let them move.
• Don’t Talk. Avoid asking questions or trying to have a conversation. They are incapable of communicating through the pain.
• Believe Them. The single most important thing you can do is validate their experience. Acknowledge the severity of what they are going through. After the attack, ask them what they need for next time.

Myths and Misunderstandings

Stigma and misinformation add an unnecessary layer of suffering for patients. Dispelling these myths is a crucial part of advocacy.

Myth: It’s just a “bad migraine” or a “sinus headache.”
Fact: Cluster headache is a distinct neurological disorder with a different underlying mechanism, symptoms, and treatment profile than migraine or any sinus condition ².

Myth: It’s caused by stress or is a psychological problem.
Fact: Cluster headache is a biological brain disorder definitively linked to the hypothalamus ³. Stress is a consequence of the disease, not its cause.

Myth: Patients are just being dramatic or seeking attention.
Fact: The restlessness is an uncontrollable neurological symptom, not a behaviour. The pain is ranked as one of the most severe known to medicine. It is a legitimate, debilitating physical disease.

When to Seek Specialist Care

The Role of a Neurologist or Headache Specialist

Given its rarity and the complexities of its management, every person with suspected cluster headache should be assessed by a neurologist. A GP with a special interest and advanced training in headache medicine can also effectively manage the condition. A specialist is essential for confirming the diagnosis, ruling out secondary causes, navigating the use of specialised medications like verapamil, and gaining access to advanced therapies if needed.

Importance of Accurate Diagnosis for Effective Treatment

You cannot treat what you do not correctly diagnose. An accurate diagnosis is the gateway to the right treatments. It ends the cycle of trial-and-error with ineffective painkillers and provides access to the specific therapies—oxygen and triptans—that can bring relief. This is why patient education and physician awareness are so paramount.

Conclusion: Hope Through Research and Advocacy

Raising Awareness for a Rare But Devastating Condition

Cluster headache may be rare, but for those who live with it, its impact is absolute. Raising the profile of this condition within the medical community and the general public is the only way to shorten diagnostic delays, reduce stigma, and ensure that every patient receives the swift, accurate, and compassionate care they deserve.

Empowering Patients Through Education and Support

Knowledge is power. Understanding the biology of cluster headache, its triggers, its timelines, and its specific treatments empowers patients to become advocates for their own health. It enables them to have more informed conversations with their doctors, track their symptoms effectively, and make confident decisions about their care. Connecting with support networks, like those fostered by Migraine & Headache Australia or Clusterbusters, provides a vital sense of community and shared understanding.

Hope Through Research and Emerging Treatments

The field of headache medicine is advancing rapidly. Research into the genetics, inflammatory mechanisms, and complex neural circuits of cluster headache is ongoing. The development of therapies targeting CGRP and neuromodulation devices like nVNS were born from this research, and they represent a new era of targeted treatment. With continued scientific investigation and strong patient advocacy, there is profound hope for even better, more effective, and more accessible therapies on the horizon.

Resources and Support

• Headache Australia: Comprehensive information, resources, and advocacy for all headache disorders in Australia. https://headacheaustralia.org.au/
• Healthdirect Australia: A government-funded service providing quality health information. https://www.healthdirect.gov.au/cluster-headache
• Pharmaceutical Benefits Scheme (PBS): Information on subsidised medicines in Australia. https://www.pbs.gov.au
• State-based Equipment Funding Schemes (e.g., EnableNSW): State government programs that may assist with funding for medical equipment like oxygen cylinders. Search for your state’s specific program.

References

1. Fischer, M., Marziniak, M., Gralow, I., & Evers, S. (2008). The incidence and prevalence of cluster headache: a meta-analysis of population-based studies. Cephalalgia, 28(6), 614–618. DOI:10.1111/j.1468-2982.2008.01592.x
2. Headache Classification Committee of the International Headache Society (IHS). (2018). The International Classification of Headache Disorders, 3rd edition. Cephalalgia, 38(1), 1–211. DOI:10.1177/0333102417738202
3. May, A., Bahra, A., Büchel, C., Frackowiak, R. S. J., & Goadsby, P. J. (1998). Hypothalamic activation in cluster headache attacks. The Lancet, 352(9124), 275–278. DOI:10.1016/S0140-6736(98)02470-2
4. Dousset, V., Laporte, A., Legoff, M., Traineau, M. H., Raffray, J., & Dartigues, J. F. (2019). Suicidal ideation in cluster headache: A nationwide study. Cephalalgia, 39(10), 1258–1267. DOI:10.1177/0333102419845660
5. Ray, J. C., Stark, R. J., & Hutton, E. J. (2022). Cluster headache in adults. Australian Prescriber, 45(1), 15–20. DOI:10.18773/austprescr.2022.001
6. Cho, S. J., Kim, B. K., Kim, B. S., & Sohn, J. H. (2022). Diagnostic Delay and Its Predictors in Cluster Headache. Frontiers in Neurology, 13, 827734. DOI:10.3389/fneur.2022.827734
7. Cohen, A. S., Burns, B., & Goadsby, P. J. (2009). High-flow oxygen for treatment of cluster headache: a randomized trial. JAMA, 302(22), 2451–2457. DOI:10.1001/jama.2009.1855
8. Ekbom, K., Krabbe, A., Micelli, G., Prusinski, A., Cole, J. A., & futuristic, C. H. S. G. (1993). Subcutaneous sumatriptan in the acute treatment of cluster headache: a dose comparison study. Acta Neurologica Scandinavica, 88(1), 63–69. DOI:10.1111/j.1600-0404.1993.tb04188.x
9. Gaul, C., Diener, H. C., Silver, N., Magis, D., Saper, J. R., Straube, A., … & Goadsby, P. J. (2016). Non-invasive vagus nerve stimulation for PREVention and Acute treatment of chronic cluster headache (PREVA). Cephalalgia, 36(6), 534–546. DOI:10.1177/0333102415607070
10. Silberstein, S. D., Mechtler, L. L., Kudrow, D. B., Calhoun, A. H., McClure, C., Saper, J. R., … & Goadsby, P. J. (2016). Non-invasive vagus nerve stimulation for the ACute Treatment of cluster headache: findings from the randomized, double-blind, sham-controlled ACT1 study. Headache: The Journal of Head and Face Pain, 56(8), 1317–1332. DOI:10.1111/head.12876
11. Therapeutic Goods Administration (TGA). (2019). Australian Public Assessment Report for Galcanezumab (Emgality). Retrieved August 18, 2025.
12. Pharmaceutical Benefits Scheme (PBS). (2025). Listing for Galcanezumab. Retrieved August 18, 2025.
13. Rozen, T. D. (2021). The clinical characteristics and attack‐related disability of cluster headache patients with side‐shift. Headache: The Journal of Head and Face Pain, 61(4), 652–659. DOI:10.1111/head.14101
14. Wei, D. Y., Yuan, H., & Goadsby, P. J. (2021). The painful truth about cluster headache and suicide. The Journal of Headache and Pain, 22(1), 1-2. DOI:10.1186/s10194-021-01241-7
15. Pearson, S. M., et al. (2019). The long-term impact of cluster headache. Current Pain and Headache Reports, 23(8), 53. DOI:10.1007/s11916-019-0792-7

Back to top