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View all frequently asked questionsA National Migraine Centre factsheet
They often wake me in the middle of the night. They build in a matter of seconds and the pain is excruciating. It’s only in my right eye, like a red-hot poker. Sometimes I pace up and down the room holding my head, or just sit in the chair and rock. I cannot imagine a more severe pain.
Cluster headache describes attacks of very severe one-sided pain in the head, usually around the eye. The pain is often described as the worst imaginable. Alongside the pain, sufferers can also experience one or more of the following:
Periods of attacks are known as bouts, in which the headaches are clustered over a few weeks or even months.
Cluster headaches in adults are relatively uncommon, affecting around one person in a thousand. Unlike other headache types, men are more commonly affected than women: there are around three men affected for every one woman.
Cluster headaches in children are even more rare and, while the condition can begin at any age, it usually starts in younger adults.
The more common type is ‘episodic cluster headache’, which accounts for nine out of ten cases. This means the symptoms come and go in bouts, often seasonally and most commonly worsening in spring and autumn. Typically, people suffer one or two bouts each year or every two years.
‘Chronic cluster headache’ is less common, accounting for one in ten cases. This is characterised by a headache that can go on for six months of more. In chronic cluster, the pain may be continuous.
Cluster headache is extremely painful. The pain always stays on the same side during a bout, but a minority of patients find cluster changes sides from bout to bout.
The pain is often described as searing, knife-like or boring in and around the eye. This reaches full force rapidly, within five to ten minutes of onset, and each untreated attack typically lasts up to an hour but can be anything between 15 minutes and three hours.
In contrast to migraine, cluster pain causes restlessness or agitation and, because it can be so severe, can cause people to bang their heads against the wall.
Pain often occurs at the same time every night (‘alarm clock pain’) and typically within minutes of drinking alcohol.
Diagnosis is usually possible based on the symptoms the patient is displaying.
In diagnosing cluster headaches, routine brain scans for people with typical symptoms are not advised. However, there have been studies which show more pituitary gland abnormalities in people with cluster, which has led some experts to scan the brain and pituitary gland in patients who do not fit normal patterns or do not respond to typical treatment.
Cluster, like migraine, is a primary headache: that is, it arises from a problem with nerve misfiring.
It is the most common form of the ‘trigeminal autonomic cephalalgias’ (TACs), a type of headache that is completely unrelated to migraine.
Experts don’t fully understand the cause of cluster headache, although current theories implicate neuro-vascular mechanisms, trigeminal nerve stimulation and blood vessel changes in the posterior thalamus, which controls our body clock and circadian rhythm.
Unlike migraine, the relationship between cluster headache and possible triggers is very uncertain.
Alcohol can often bring on an attack during the bout within minutes, although avoiding alcohol won’t end a bout.
There does seem to be an association between smoking and cluster headache, although quitting smoking has not been shown to help.
Other recognised triggers include exercise, strong smells (such as paint, nail varnish and petrol) and high temperatures.
However, addressing triggers is much less helpful for cluster headache than it is for migraine.
Fortunately for many sufferers, particularly those with chronic cluster headache, cluster often improves in later life.
Bouts of episodic cluster are obviously temporary, but they do tend to recur over time.
Over-the-counter or simple painkillers don’t work and can make things worse with side effects. Effective treatment needs expert medical advice and prescription-only drugs.
Because cluster headache is relatively uncommon, many non-specialist doctors are inexperienced in diagnosing and treating it.
You can book an appointment with a headache specialist through the National Migraine Centre here.
It can also be helpful to take this factsheet to appointments with your GP.
More resources are available from the Organisation for the Understanding of Cluster Headache.
As this is a relatively rare condition, most people with cluster will need to see a headache specialist, which you can access through the NHS or the National Migraine Centre.
Without expert help, many sufferers can go years without having access to either diagnosis or effective treatment.
For episodic cluster, the usual starting regime is:
Many people respond to verapamil 120mg three times daily, but higher doses, up to 360mg three times daily, may be necessary.
The effective dose should be continued for the usual duration of the cluster, then gradually tapered over a few weeks.
If attacks recur, the dose can be increased again and reduced at two-week intervals.
Verapamil is usually well tolerated, although constipation (which may be severe), acid indigestion and flushing can happen.
Good dental care is important as gum bleeding from gum overgrowth (gingival hyperplasia) can occur.
People taking verapamil to prevent cluster headache should have an electrocardiogram (ECG) before treatment starts and with every dose change, to rule out heart rhythm problems, which can be caused or worsened by this drug.
High flow (100 per cent) oxygen is a possible alternative to sumatriptan, particularly if you have more than two attacks per day, although it is not always as convenient as sumatriptan.
Oxygen is delivered at up to 12 litres per minute through a non-rebreathing mask for up to 20 minutes. You should sit leaning forward with the mask firmly over your face ensuring it is a tight fit and there are no leaks. Your doctor will need to organise this via a Home Oxygen Order Form (HOOF). Some people find that oxygen simply delays the attack.
Triptans in tablet form should be avoided as they take too long to have an effect.
Alternatives to verapamil include lithium, melatonin and topiramate.
Greater occipital nerve (GON) blocks are worth considering to end a bout, as is a trial of indomethacin. You can find out more about booking a GON block through the National Migraine Centre here.
The new anti-CGRP medications may have a use for the treatment of cluster headache but only one (galcanezumab) has been shown to be helpful so far and even then there is no evidence it helps with chronic cluster headache. You can find out more about arranging an anti-CGRP prescription through the National Migraine Centre here.
Some studies show that non-invasive stimulation of the vagus nerve via a device called a GammaCore can be useful for reducing pain during attacks. It may have benefits in preventing chronic cluster headaches too when used alongside other treatments. GammaCore is now available through the NHS.
Difficult cases that don’t respond to these treatment options may be considered for surgical treatment, involving brain or occipital nerve stimulation.
Listen to the National Migraine Centre’s Heads Up podcast special on cluster headache episode 3 in series 2 here.
Get more advice and information from the Organisation for Understanding Cluster Headache, which operates a helpline.
Book an appointment with the experts: review the best treatment options for you with a leading headache specialist. Book your consultation through the National Migraine Centre now.
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