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. 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 headache is 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 headache can be divided into two distinct categories.

Cluster Headache vs. Migraine

Cluster headaches are headaches that come in groups (clusters) separated by pain-free periods of months or years.

  • During the period in which the cluster headaches occur, pain typically occurs once or twice daily, but some patients may experience pain more than twice daily.
  • Each episode of pain lasts from 30 to 90 minutes.
  • Attacks tend to occur at about the same time every day and often awaken the patient at night from a sound sleep.
  • The pain typically is excruciating and located around or behind one eye.
  • Some patients describe the pain as feeling like a hot poker in the eye. The affected eye may become red, inflamed, and watery.
  • The nose on the affected side may become congested and runny.

Unlike patients with migraine headaches, patients with cluster headaches tend to be restless. They often pace the floor, bang their heads against a wall, and patients can be driven to desperate measures including contemplating suicide.

What causes 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 headache, 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 headache 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 to 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.


Migraine or Tension Headache? Symptoms, Triggers, Treatments See Slideshow

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 migraine headaches, including sensitivity to light, sounds, or odors may occur. However, unlike migraine headache, movement does not worsen the pain of a cluster headache. In fact, many people describe a sense of restlessness during their pain.
  5. The headaches associated with cluster 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 headache 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.

Which medications are used the treatment of pain management, prevention, and other symptoms of cluster headaches?

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

Oxygen deliverey: Delivering oxygen by a face mask has been shown to help a majority of people within a short period of time. 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) has been shown to be beneficial in many of patients with cluster headache. 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 can be extremely effective to decrease a 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 are being studied as possible options with less risk of permanent nerve change.


Who suffers more frequently from migraine headaches? See Answer

What is the prognosis for cluster headaches? Are they life threatening, can they be cured?

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

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.

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Medically Reviewed on 11/3/2020
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Blanda, M, MD, et. al. Cluster Headache. Medscape. Updated: Apr 25, 2017.

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