Cluster Headache

Cluster headache is a relatively rare but extremely painful type of headache, usually strictly one- sided, attacks in cyclical pattern and bouts (1). It occurs in about one in 1000 people, often starts in 20-40 years of age. Males are about three times more likely to be affected than females (2). It occurs rarely in children and is extremely rare after 70-75. The term ‘cluster’ is used as the attacks usually occur in groups or clusters, typically for several weeks once or twice a year at the same time of year. The cause of cluster headache is thought to be a disorder of an “internal clock” in the hypothalamus.

These are episodic cluster headaches, although if the clusters have no period of remission, or the remission period is less than three months, it’s classified as a chronic cluster headache disorder. During a cluster period, people will experience 1-8 attacks per day, lasting between 15 minutes to 3 hours. Many studies show a link with cigarette smoking. Cluster headaches can not be ‘cured’, but the pain can be managed with preventative medications to prevent attacks and acute treatment to rapidly relieve pain.

Cluster headache belongs to a category of primary headache disorders called ‘trigeminal autonomic cephalalgias (TACs)‘.

Symptoms

Attacks tend to happen at night or in the early hours of morning, waking people from sleep. The attack is usually a deep, intensive pain around/behind the eye or in the temple. Tearing, running nose, redness of the eye, puffy or droopy eyelid on the affected side are other classical features. It typically causes excruciating, boring (or ‘drilling’) pain localised around one eye, which can spread to the forehead, temple, cheek, and upper gum. Other associated symptoms include bloodshot, irritated eyes, swollen eyelids, stuffy nose (nasal congestion), sweating, agitation, and feeling restless. The affected individuals often feel agitated, restless with a tendency to pace and/or push the painful area with their hands. The pain builds up quickly once it starts with each attack lasting for 15 mins to 180 mins, up to eight attacks a day(2).

Types of cluster headache

Cluster headache is further divided into episodic and chronic subtypes based on the length of break between attacks(3). In episodic type, there are usually bouts of attacks, more frequent in spring and autumn. The bouts tend to last for 6-12 weeks with break of more than 3 months. Chronic cluster headache, on the other hand, has break that is shorter than three months.

Risk factors

While there is no good evidence to support a causal relationship between smoking and cluster headache, smokers are found to have more severe attacks in episodic cluster headache but not in chronic cluster headache.

Triggers

The common triggers include (1, 4):

Alcohol, particularly red wine
Food containing nitrites such as beets, garlic, meat, dark chocolate, etc.
Strong odours such as petroleum, perfume, paint, nail varnish, etc.
Certain medications such as nitroglycerin, a medication for chest pain
Seasonality

Diagnosis

Doctors usually diagnose cluster headache by taking a careful history of your symptoms. However, delay in diagnosis is common for this condition can be confused with other type of headaches, for example, migraine. For this reason, seeing a neurologist or headache specialist is sometimes necessary.

Treatment & Prevention

Dr. Michael Eller, a headache specialist, discusses treatments for cluster headache from 12:18 in this presentation during Migraine & Headache Awareness Week.

Commonly used treatment for acute attacks include:

High flow oxygen inhalation via facemask
Triptans, a class of headache medication, in the form of nasal spray or tablet

Avoiding triggers is recommended.

Headache preventative treatment is usually needed if attacks are frequent. Treatment options include oral medications, neuromodulation and Calcionin Gene-/related Peptides (CGRP).

Consulting a neurologist/headache specialist is often required for the above therapies.

Prognosis

Cluster headache is not a life threatening condition and is not known to cause damage in the brain. Headache attacks can become infrequent and/or less severe with treatment or by itself and sometimes people can be free of headaches for several years. Headache frequency also tends to decrease in older age (2).

References

Nesbitt AD, Goadsby PJ. Cluster headache. BMJ. 2012;344:e2407.
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.
Burish M. Cluster Headache and Other Trigeminal Autonomic Cephalalgias. Continuum (Minneap Minn). 2018;24(4, Headache):1137-56.
Rozen TD, Fishman RS. Cluster headache in the United States of America: demographics, clinical characteristics, triggers, suicidality, and personal burden. Headache. 2012;52(1):99-113.