Cluster Headaches

Medically Reviewed on 3/2/2023

What is a cluster headache?

Cluster headaches are intense cyclical, one-sided headaches. The triggers for this type of headache disorder are not clear, but they may have to do with blood vessels in the eye and sinuses or misfiring neurons.
Cluster headaches are intense cyclical, one-sided headaches.

A cluster headache is a pain that occurs along one side of the head. It's frequently described as pain that occurs around, behind, or above the eye and along with the temple in cyclic patterns or clusters. The pain of a cluster headache is very severe. Many patients describe a “drilling” type of sensation.

The treatment of cluster headaches can be divided into two distinct categories:

What are two types of cluster headaches?

The two main types of cluster headaches include the following:

  1. Episodic cluster headaches: Occurs in cycles of headaches with periods of remission. These cycles last between 15 minutes to 3 hours and can occur daily or several times a day. Cluster periods may last several weeks to months.
  2. Chronic cluster headaches: Less common than episode cluster headaches, chronic cluster headaches do not stop completely during remission periods. These headaches last for a year or more without any break. Headaches occur daily or multiple times per day.

What is the reason of cluster headaches?

The specific cause and anatomic origination of cluster headaches aren't known. MRI studies suggest dilation of the ophthalmic artery during an acute cluster headache, while PET scans reveal activity within the cavernous sinus. However, many patients with other headache types also have revealed abnormalities in similar regions, so these tests aren't definitive. There is some evidence that the hypothalamus may be involved in the recurrence cycle of cluster headaches. Activation of the trigeminal ganglion can cause many changes associated with cluster headaches, but the trigger for activation of this region hasn't been identified.

Do women get more cluster headaches than men do?

Males are two to four times more likely to develop cluster headaches than females; however, the overall frequency is quite low, with a prevalence rate of about 1 per 1,000. Because of the rarity of the condition, limited information is available.

Although the majority of people are adults, cluster headache has been reported in children as young as 6 years of age.

What triggers cluster headaches?

Trigger: Hormonal Changes
Many women's attacks are linked to their menstrual cycle.

Many patients report their headaches begin while sleeping. Additionally, alcohol can trigger cluster headaches in patients who are in the midst of a cycle. Histamines and nitroglycerin can trigger cluster headaches in patients. Seasonal variation has been described, although this is inconsistent for many patients. Some patients have clusters precipitated by environmental changes or changes in stress or activity levels. Hormonal factors, or menstruation, do not seem to trigger cluster headaches. Other risk factors include smoking and a family history of the problem.


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What are the signs and symptoms of cluster headaches?

Cluster headache is always unilateral, or one-sided. However, some people may experience some variability of the side on which their headache occurs. Most people with cluster headaches describe their pain as occurring around or behind the eye. Pain may radiate along the forehead, into the jaw or along the gum line and into the teeth, or across the cheek of the affected side. Infrequently, pain may extend into the ear, neck, or shoulder.

In addition to head pain, many people with cluster headaches have symptoms and signs that may include:

  1. Watering of the eye (tearing). Some people may only experience some redness of the conjunctiva.
  2. Eyelid drooping or swelling
  3. Runny nose (rhinorrhea)
  4. People with cluster headaches also may have symptoms that are more commonly associated with migraine headaches, including sensitivity to light, sounds, or odors may occur. However, unlike a migraine headache, movement does not worsen the pain of a cluster headache. Many people describe a sense of restlessness during their pain.
  5. The headaches associated with clusters occur in groups. While the headaches themselves may be brief (as short as 15 minutes), the headaches can recur up to eight times in 24 hours. Headaches may last as long as 3 hours. Cluster cycles may last for only a single day, or may linger for many weeks.

What procedures and imaging tests diagnose cluster headaches?

The diagnosis of cluster headaches is typically made after the history of headaches has been explored and a physical examination is completed. Cluster headaches are unique in their presentation, and often the history is sufficient to make the diagnosis.

While no imaging study or specific blood test can confirm the diagnosis of cluster headache, an MRI or CT scan of the brain may be ordered to confirm that there are no other contributing factors that may mimic cluster headache symptoms. In some cases, ophthalmologic evaluation is needed to exclude problems within the eye itself that may be causing symptoms.

How do you relieve cluster headaches?

The treatment of cluster headaches can be divided into two distinct categories -- relief of the acute headache and prevention of future headaches.

  • Oxygen delivery: Delivering oxygen by a face mask has been shown to help a majority of people within a short period. However, this can be unwieldy, and most people are unable or unwilling to transport oxygen canisters if they need to travel.
  • Injectable sumatriptan (Imitrex, Alsuma, Samavel DosePro): This is beneficial in many patients with cluster headaches. This treatment is contraindicated in patients with cardiac disease or untreated hypertension. Nasal spray or oral versions of this medication have been less effective than the injectable.
  • Dihydroergotamine: Given intravenously, can be extremely effective in treating a cluster headache, but can be difficult to administer acutely and cannot be used if a patient has used sumatriptan in the preceding 24 hours.
  • Intranasal lidocaine: Has been suggested as a treatment option, but must be administered in a specific manner and is ineffective if not given correctly.
  • Steroids: These can be extremely effective to decrease the headache cycle. Steroids should not be used frequently, and are for short-term use only as long-term use can lead to significant complications.
  • Verapamil (Calan, Varelan), lithium (Lithobid, Eskalith), valproic acid (Depakote, Stavzor), topiramate (Topamax, Quedxy, Topiragen, Trokendi XR), and melatonin: Can all be of benefit in reducing the frequency and severity of cluster cycles.
  • Surgery: For intractable cases has been suggested. Radiofrequency lesioning of the trigeminal ganglion can decrease cluster headache frequency but is associated with significant side effects and nerve loss.
  • Gamma knife lesioning and deep brain stimulation: These are being studied as possible options with less risk of permanent nerve change.

How do you break a cluster headache cycle?

While it may be challenging, you can try to break a cluster headache cycle through the following treatment options:

  • Oxygen therapy
  • Triptans
  • Local anesthetics
  • Prevention medications (verapamil, corticosteroids, and lithium)
  • Nerve stimulation

How can you prevent cluster headaches?

Once cluster headaches have been accurately diagnosed, long-term treatment can be beneficial to decrease or prevent future cycles. However, as the specific underlying cause isn't known, it may take some time to control the headache cycles.

Are cluster headaches harmful?

Over time, cluster headache seems to diminish in frequency, but this may take many years. Cluster headaches can go into remission for an extended period and then recur. As such, a discussion with your physician regarding the need for continuation of treatment is warranted.

Cluster headache does not appear to be associated with other neurological illness, such as Alzheimer's dementia, Parkinson's disease, or multiple sclerosis (MS); however, many individuals with multiple sclerosis are known to experience severe headaches.

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Medically Reviewed on 3/2/2023
Bahra, A., et al. "Cluster headache: a prospective clinical study with diagnostic implications." 58.3 (2002): 354-361.

Blanda, M, MD, et. al. Cluster Headache. Medscape. Updated: Apr 25, 2017.

Dodick, D. W., et al. "Cluster headache." Cephalalgia 20.9 (1994): 787-803.