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.
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. 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).
Cluster headaches 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.
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.
The common triggers include (1, 4):
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.
Commonly used treatment for acute attacks include:
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.
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).
Reviewed by Dr Lin Zhang, MBBS, MSc, FRACP, Department of Neurosciences, Alfred Hospital, Melbourne. October 2019.