Cluster headache explained

What cluster headache is

Cluster headache is a distinct type of headache, separate from migraine and tension headache. Attacks are strictly one-sided and centre on or around one eye or the temple, with a boring, piercing or burning quality that people often describe as the worst pain they have ever felt. Each attack is relatively short, typically lasting between 15 minutes and 3 hours, but they can strike several times a day, often at the same times, and frequently wake people from sleep in the early hours. The name comes from the way attacks cluster together over a period — a bout — separated by pain-free spells. It is uncommon, affects men more often than women, and usually starts in adulthood. Because it is so severe and specific, recognising the pattern is key to getting the right treatment.

Symptoms and how it differs from migraine

During an attack, alongside the severe one-sided pain, there are usually clear signs on the same side as the pain: a red and watering eye, a drooping or swollen eyelid, a smaller pupil, and a blocked or runny nostril. Many people also feel restless and agitated, pacing or rocking, unable to keep still — which is different from migraine, where people usually want to lie quietly in a dark room. Migraine attacks tend to last longer (hours to days), often come with nausea and sensitivity to light and sound, and may have a warning aura. Cluster headache is shorter, sharper, strictly one-sided, and comes with those eye and nose changes. Telling them apart matters because the treatments differ. If your headaches follow the cluster pattern, it is important to mention these features to your doctor.

Bouts, triggers and diagnosis

Cluster headache usually runs in bouts. In the common episodic form, attacks come daily for weeks or months and then stop for months or years before returning; in the rarer chronic form, they continue with little or no break. During a bout, alcohol is a powerful trigger and often brings on an attack within an hour, so people usually avoid it until the bout ends. Strong smells, heat and changes in sleep pattern can also trigger attacks. Diagnosis is made mainly from the typical story — the timing, one-sidedness and eye and nose signs — as there is no specific test. A doctor will check for warning features and may arrange a brain scan to rule out other causes, especially if the pattern is unusual. Keeping a headache diary noting timing, length and symptoms can really help diagnosis.

How attacks are treated

Ordinary painkillers taken by mouth work too slowly to help a cluster attack, which peaks fast, so specific treatments are used. Two main options can stop an attack quickly: breathing in high-flow oxygen through a mask, and fast-acting triptan medicines given by injection or nasal spray rather than as tablets. These are prescribed and set up through your GP or a specialist, and oxygen requires special arrangements to have at home. Because attacks come on suddenly and are so severe, having these treatments ready and knowing how to use them makes a big difference. It is important not to overuse painkillers, which are largely ineffective here and can cause other problems. A neurologist's involvement is often recommended to confirm the diagnosis and organise the right acute treatments.

Prevention and living with it

Because attacks are so severe, preventing them during a bout is a key goal. Specialists can prescribe preventive medicines taken regularly through a bout to reduce how often attacks happen, and a short course of another medicine is sometimes used to settle a bout quickly. Avoiding alcohol and other personal triggers during a bout helps, and keeping regular sleep patterns may reduce attacks. For the small number of people with severe chronic cluster headache that does not respond to usual treatment, specialist centres can consider other approaches, including nerve-stimulation techniques. Living with cluster headache is hard, and the pain and disruption can affect mood, work and relationships, so support matters. A neurologist, your GP and patient organisations such as OUCH (UK) can offer treatment, advice and reassurance that effective help is available.