Overview – cluster headache (CH)
Cluster headaches, which occur in cyclical patterns or cluster periods, are one of the most painful types of headache. A cluster headache commonly awakens you in the middle of the night with intense pain in or around one eye on one side of your head.
Bouts of frequent attacks, known as cluster periods, can last from weeks to months, usually followed by remission periods when the headaches stop. During remission, no headaches occur for months and sometimes even years.
Fortunately, cluster headache is rare and not life-threatening. Treatments can make cluster headache attacks shorter and less severe. In addition, medications can reduce the number of cluster headaches you have.
Pathophysiology of cluster headache
The pathophysiology of cluster headache is not fully understood. Current theories implicate mechanisms such as vascular dilation, trigeminal nerve stimulation, and circadian effects. Histamine release, an increase in mast cells, genetic factors, and autonomic nervous system activation may also contribute.
Acute cluster headache involves the activation of posterior hypothalamic gray matter and is inherited as an autosomal dominant condition in about 5% of patients. Having a first-degree relative with cluster headache increases the risk 14- to 39-fold. One study showed an association between cluster headache and the HCRTR2 gene. Disturbed circadian rhythms have been suggested as a possible contributor because headaches often begin during sleep.
Causes of cluster headache
Doctors do not know exactly what causes cluster headaches. They seem to be related to the body’s sudden release of histamine (a chemical in the body released during an allergic response) or serotonin (chemical made by nerve cells) in the area of a nerve in the face called the trigeminal nerve. A problem in a small area at the base of the brain called the hypothalamus may be involved.
More men than women are affected. The headaches can occur at any age but are most common in the 20s through middle age. They tend to run in families.
Cluster headaches may be triggered by:
Alcohol and cigarette smoking
High altitudes (trekking and air travel)
Bright light (including sunlight)
Exertion (physical activity)
Heat (hot weather or hot baths)
Foods high in nitrites (bacon and preserved meats)
Risk Factors of cluster headache
Cluster headaches are rare, affecting less than 1% of the population.
Cluster headaches can affect all ages, from children to older people, but are most common from young adulthood through middle age. In men, the typical age of onset is in the 30s. In women, cluster headaches usually develop in the 60s.
Men are 3 to 4 times more likely to have cluster headaches than women. Unlike with migraines, fluctuations in estrogen and other female hormones do not appear to play a role in cluster headaches.
Lifestyle factors play a role in cluster headaches. They include:
Alcohol consumption is a major risk factor. Alcohol, especially red wine and beer, is the most common attack trigger during active periods of headaches.
Cigarette smoking and tobacco products are risk factors for cluster headaches. These headaches are more common in people who smoke. However, quitting smoking does not appear to stop attacks.
Emotional stress and physical exertion are risk factors for triggering cluster headaches.
Cluster headache attacks often coincide with times of seasonal change, such as in spring or autumn. Changes associated with daylight savings during these times of year may alter the normal sleep-wake cycle and trigger attacks.
Family History and Genetic Factors
Cluster headaches tend to run in families, suggesting that a genetic component may be involved. Cluster headache may occur more commonly in people with a “type A” personality.
History of Migraine
About half of people with cluster headache have a personal or family history of migraine. It is possible for people to have both kinds of headache.
Head injury with brain concussion appears to increase the risk of cluster headaches, although a causal relationship has not been proven.
Cluster headaches tend to occur during specific sleep stages and are associated with several sleep disorders, including narcolepsy, insomnia, restless legs syndrome, and sleep apnea.
Symptoms of a cluster headache
Cluster headaches generally reach their full force within five or ten minutes after onset. The attacks are usually very similar, varying only slightly from one attack to another.
Type of pain
The pain of a cluster headache is one-sided, and during a headache period, the pain remains on the same side. When a new headache period starts, it rarely occurs on the opposite side.
Severity/intensity of pain
The pain of cluster headache is generally very intense and severe and is often described as having a burning or piercing quality. It may be throbbing or constant. The pain is so intense that most cluster headache sufferers cannot sit still and will often pace during an attack.
Location of pain
The pain is located behind one eye or in the eye region, without changing sides. It may radiate to the forehead, temple, nose, cheek, or upper gum on the affected side.
The scalp may be tender, and the pulsing in the arteries often can be felt.
Duration of pain
The pain of a cluster headache can last anywhere from 15 minutes to three hours. In general, the headaches last for 30 to 90 minutes. The headache will disappear only to recur later that day. Typically, in between attacks, people with cluster headaches are headache-free but the pain can sometimes linger.
Frequency of headaches
Most sufferers get one to three headaches per day during a cluster period (the time when the headache sufferer is experiencing daily attacks). They occur very regularly, generally at the same time each day, and they often awaken the person at the same time during the night.
The cluster periods can last from two weeks to three months and then disappear completely for months or years. The episodic cluster headache sufferer has variable pain-free intervals between headache attacks.
Complications – cluster headache
The pain of cluster headaches can be intolerable. Fortunately, as people age, the attacks tend to cease, although no one can predict when they will end.
Effects on Mental and Emotional Functioning
Anxiety and depression are common among people with cluster headaches, which can affect functioning and quality of life. The pain can be so intense that some people consider, or attempt, suicide.
Effects on Sleep
Nighttime attacks can interfere with sleep and lead to sleep deprivation. Lack of sleep can increase the risk of depression, and other physical and emotional problems.
Auras and Stroke
Some people with cluster headaches experience migraine-like aura. Research suggests that headaches that are accompanied by aura may increase the risk of stroke or transient ischemic attack (TIA). TIA symptoms are similar to those of stroke but last only briefly. However, people who have had a TIA are at increased risk for later having a stroke. People with cluster headaches may have risk factors for stroke, such as smoking. However, there currently is no data that indicates a cluster headache increases the risk of stroke.
Diagnosis and Test for cluster headache
Cluster headache has a characteristic type of pain and pattern of attacks. Diagnosis depends on your description of the attacks, including your pain, the location, and severity of your headaches, and associated symptoms.
How often your headaches occur and how long they last also are important factors.
Your doctor will likely try to pinpoint the type and cause of your headache using certain approaches.
A neurological examination may help your doctor detect physical signs of a neurological disorder. The exam is usually normal in patients with cluster headaches. Your doctor will use a series of procedures to assess your brain function, including testing your senses, reflexes, and nerves.
Doctors will also assess a person’s medical history with a focus on whether the person’s symptoms could relate to any other headache disorders, and find out whether a person has a family history of cluster headaches. Although the link between genetics and CHs is not understood, people with relatives affected by CHs are more likely to develop the condition.
If you have unusual or complicated headaches or an abnormal neurological examination, your doctor might recommend other tests to rule out other serious causes of head pain, such as a tumor or an aneurysm. Common brain imaging tests include:
MRI. This uses a powerful magnetic field and radio waves to produce detailed images of your brain and blood vessels.
CT scan. This uses a series of X-rays to create detailed cross-sectional images of your brain.
Finally, doctors will find out whether a person’s experience of their headache(s) matches the diagnostic criteria for a cluster headache, which include:
Having at least one symptom which is ipsilateral (on the same side of the head as the pain) in the eye, nose or face
Restlessness or agitation
A duration of 15 minutes to three hours without effective response to medication or painkillers
A frequency of between one attack every other day or eight attacks per day and an incredibly severe pain
Avoiding misdiagnosis of cluster headache
Doctors will be aware that a person may be affected by other primary headache disorders, which may result in them experiencing headaches that are similar to cluster headaches. These include:
Trigeminal neuralgia. A chronic pain disorder affecting the same nerve that is involved in cluster headaches.
Migraine. Some headache attacks can feature autonomic features such as teary eyes. Migraines can also often occur in bouts, which leads to the widespread misconception that a person is experiencing cluster headaches when they are in fact experiencing clusters of migraines.
Hemicrania continua. A chronic, persistent headache that usually occurs on the same side of the face and head, usually consisting of a constant dull pain which intermittently becomes piercing.
Short-lasting, unilateral, neuralgiform headache attacks with conjunctival injection and tearing (SUNCT). Like CHs, SUNCT headaches are a subtype of trigeminal autonomic cephalalgia headaches, but their duration is much shorter than cluster headaches.
Treatment for Cluster Headaches
Treatment involves relieving and preventing your headache symptoms using medication. In rare cases, when pain relief and preventive treatment do not work, your doctor may recommend surgery.
Pain medication relieves your headache pain once it has begun. Treatments include:
Oxygen: Breathing 100-percent pure oxygen when the headache begins can help relieve symptoms.
Triptan medications: A nasal spray medication called sumatriptan (Imitrex), or other tripitan medications constrict blood vessels, which can help ease your headache.
DHE: An injected medication called dihydroergotamine (DHE), can often relieve cluster headache pain within five minutes of use. Note: DHE can’t be taken with sumatriptan.
Capsaicin cream: Topical capsaicin cream can be applied to the painful area.
Preventive medications stop headaches before they start. These medications may not be 100-percent effective, but they can reduce the frequency of your headaches. These medications include:
Blood pressure medications, such as propranolol (Inderal) or verapamil (Calan, Covera, Isoptin, Verelan), which relax your blood vessels
Steroid medications, such as prednisone, which reduce nerve inflammation
A medication called ergotamine that keeps your blood vessels from dilating
Anti-seizure medications, such as topiramate (Topamax) and valproic acid
Muscle relaxants, such as baclofen
As a last resort, a surgical procedure can be used to disable the trigeminal nerve. The surgery can cause permanent pain relief for some patients, but serious side effects, such as permanent facial numbness, can result.
These moves can help you avoid cluster headaches:
Keep a regular sleep schedule: A change to your routine can kick off a headache.
Skip alcohol: Any type, even beer, and wine can trigger a bout of headaches when you’re in a cluster series.
How to prevent a cluster headache?
The patient should avoid known headache triggers to the extent possible. For example, disturbances in the sleep cycle can induce attacks. Strong emotions and excessive physical activity may also induce attacks.
Tobacco may slow responsiveness to medications. Narcotics may expedite the transformation of episodic CH to chronic CH.