Patient information from BMJ

Cluster headaches: what are they?

Last published:Sep 14, 2022

Cluster headaches are attacks of very severe pain on one side of the head. They can happen up to several times a day over a period of several weeks.

Standard painkillers, such as paracetamol, don’t work for cluster headaches. But specialist treatments can help prevent and treat them. You can use our information to talk with your doctor about the best treatments for you.

What are cluster headaches?

As the name suggests, cluster headaches are brief but very severe headaches that happen in clusters, sometimes more than once a day, over several weeks.

An episode of cluster headache can last between 15 minutes and three hours. The frequency of the attacks can vary from one every two days to eight times a day.

The period of time when the headaches happen is called the cluster period. It can vary from one week to one year. But in most people it lasts two or three months.

At the end of a cluster period, most people go for at least three months, and sometimes for years, without headaches. This period without headaches is called remission.

But some people get chronic cluster headaches (chronic means long-lasting). This means that they don’t get spells of remission.

What causes cluster headaches?

There seems to be a genetic link to cluster headaches. This means that people are more likely to get cluster headaches if they have family members who get them.

Several other things have been suggested as causes of cluster headaches, including:

• heavy smoking

• heavy drinking

• sleep apnoea, and

• a history of head injuries.

But there isn’t much evidence to support these ideas. The truth is that we don’t really know why most people get cluster headaches.

Some people say that certain triggers can bring on cluster headaches. These include things like drinking alcohol, and strong chemical-type smells, such as perfume, paint, and petrol.

Who gets cluster headaches?

Cluster headaches are not common. What we know about who gets them is that:

• they seem to affect about one in every 500 people

• they usually begin between the ages of 30 and 40 years although, very rarely, they can happen in young children

• men are between two and four times more likely than women to get cluster headaches.

What are the symptoms?

The kind of headaches that most of us get from time to time cause a dull, throbbing pain.

They are not pleasant, but they are not always severe. And they usually go away if you take some painkillers, lie down for a while, or drink some water.

A cluster headache is a different type of headache. The pain of cluster headaches:

• usually comes on very quickly

• is sharp and extremely severe

• tends to be on one side of the head, although in some people it can move from one side to the other

• is often around an eye, temple, or sometimes in the face

• tends to be on the same side each time.

As well as severe pain, cluster headaches usually cause other symptoms, which can include:

• extreme agitation and restlessness. Most people can’t stay still during an attack

• red, watery eyes

• a blocked or runny nose

• sweating on the face

• nausea and vomiting

• needing to avoid bright light (this is called photophobia) and noise (this is called phonophobia)

• a swollen, droopy eyelid on the side of the face affected by the headache, and

• the pupil of the affected eye becoming smaller.

If you see your doctor with symptoms of cluster headaches, he or she might suggest that you have a scan. The scan can’t tell if your pain is caused by cluster headaches, but it might be able to rule out other causes.

To find out more about ways to prevent and treat cluster headaches, see our leaflet: Cluster headaches: what treatments are available?

What to expect in the future?

Cluster headaches can be difficult to live with. They are extremely unpleasant, and treating them can be complicated and troublesome to manage.

Some people suffer from depression as a result of having cluster headaches. If you find yourself becoming depressed, don’t keep these feelings to yourself. Talk to your doctor, and to family and friends.

But there is some good news:

• cluster headaches don’t lead to any long-term physical problems. For example, unlike some types of headache, they’re not a possible sign of something more serious, and

• in many people the symptoms become less severe as they get older.

When you first start treatment you should be seen by a neurologist. Neurologists specialise in conditions like cluster headaches that affect the nervous system. Your usual doctor might also want to check how you’re doing from time to time.

Your doctor might also be able to put you in touch with a support group.

For example, in the UK, the Organisation for the Understanding of Cluster Headache (ouchuk.org) offers support and guidance for people living with cluster headaches and their families.