Cluster headache

When a cluster headache strikes, a very intense piercing, sharp or burning pain quickly builds up around one eye. The temple and part of the forehead next to it may hurt a lot too. Some people say the pain feels like someone is pushing a nail through one of their eyes.

That eye is often red and watery. Other possible symptoms include the following:

• Stuffy or runny nose
• Sweating on the forehead or face
• Small pupil in the eye
• Swollen or drooping eyelid
• Sensitivity to sound or light

Because the pain gets slightly better when you move, many people are restless and, for instance, walk around during an attack. After 15 minutes to 3 hours, the pain usually disappears as suddenly as it started. The symptoms typically occur on the same side of the head every time.

It is not clear what causes cluster headaches. One possible explanation is that the nerve cells in certain parts of the brain are overactive (those that are also responsible for regulating our body clock). Cluster headaches also sometimes run in families, so genes may play a role.

Like migraines, cluster headaches can be triggered by certain substances or situations. For example, many people who have cluster headaches get them after drinking alcohol. Other possible triggers include

• high altitudes (for instance, being high up in the mountains) and
• nitroglycerin-containing medications (like drugs to relieve chest tightness in coronary artery disease).

But these triggers only cause attacks if the person is in an active "cluster period" phase, where they tend to have frequent attacks.

Some people say that particular smells can trigger their cluster headaches. Foods like certain cheeses or sausage products are often said to cause cluster headaches too. But there is no proof that this is true.

Only about 1 in 1,000 people have cluster headaches. So this type of headache is very rare compared to tension headaches and migraines.

Cluster headaches are three times more common in men than in women. They can happen at any age, but usually start between the ages of 20 and 40.

Cluster headache attacks typically only strike during particular phases. These phases, known as cluster periods, last for several days or weeks. Two cluster periods are often separated by quite a long symptom-free period – sometimes lasting up to several years. Cluster periods often occur in the spring or fall.

During a cluster period, attacks can strike every other day or up to several times a day. They often start at the same time of day, particularly in the early hours of the morning or one to two hours after falling asleep.

15 out of 100 people who have cluster headaches get them particularly often: Their cluster periods last for at least a year – or the pain-free interval between two cluster periods lasts less than a month. They are then considered to have chronic cluster headaches. Sometimes people have less frequent (episodic) cluster headaches at first, and then the headaches become chronic. This is more likely to happen if the cluster headaches first start in older age. But chronic cluster headaches can become episodic too.

Doctors can diagnose cluster headaches based on an in-depth chat about past and current symptoms (medical history) and a physical exam. The physical exam includes neurological tests to assess how strong your muscles and sense of touch are. To make sure that the pain is not being caused by another medical condition, you will usually have a magnetic resonance imaging (MRI) scan of your head.

There is no known way to generally prevent cluster headaches from developing in the first place. But individual attacks can be prevented by finding out what triggers them and then avoiding those triggers. It can help to keep a headache diary, where you write down things like what you ate, drank or did before an attack.

Various medications can help to prevent frequent attacks. Some contain lithium carbonate or corticosteroids, but most contain the drug verapamil. Verapamil can cause side effects like an irregular heartbeat, though, and it’s not officially approved for the treatment of cluster headaches in Germany (“off-label use”).

Painkillers like ibuprofen or acetaminophen (paracetamol) don’t relieve acute cluster headaches. But many people find that inhaling pure oxygen helps. You need special equipment and a face mask to do this. It is important to make sure you reach a high enough oxygen concentration. For this reason, you have to wear a mask that covers your mouth and nose.

Two migraine medications (triptans) can help to relieve cluster headaches when injected or used as a nasal spray. You might have to stay in the hospital at the start of the treatment.

Cluster headaches are sometimes so painful that people say they're unbearable. It is usually impossible to focus on other things, do everyday tasks, or drive a vehicle during an attack. Cluster periods affect your work and family life, and make it more difficult to participate in leisure activities. Another problem is that the headache attacks often strike at night and interfere with your sleep. Also, many people don’t know what’s wrong with them for a long time. Some worry that they might have a life-threatening disease. Cluster headaches can be so bad that some people even lose the will to live.

Many are relieved when they find out that they have a headache disorder and that it can be treated effectively. Depending on the treatment, you may have to learn some new skills – like handling an oxygen mask or injecting medication under your skin.

When people are ill or need medical advice, they usually go to see their family doctor first. In our topic "Health care in Germany" you can read about how to find the right doctor – and our list of questions can help you to prepare for your appointment.

There are various types of support for people who have cluster headaches, including support groups and information centers. In Germany, there are many regional differences in how these services are organized. You can use our list to help find local support offers.