Cluster headaches occur several times a day. They start suddenly, last for a limited time, and can be very painful.
Attacks occur cyclically. A bout of regular attacks, known as a cluster period, can last a few days, weeks, or months. This is followed by remission periods, during which there are no headaches.
Cluster headaches are not common. They are thought to affect about 1 in every 1,000 people. Six out of 10 cases involve men, and most of these are smokers. It usually starts after the age of 20 years.
Fast facts on cluster headaches
Here are some key points about cluster headaches. More detail is in the main article.
Cluster headaches normally affect one side of the head and the area around the eyes. There may be a reddened eye on the affected side of the head and a stuffy nose.
In northern countries, they are more common during the fall.
They affect around 1 in 1,000 people, and males are more likely to be affected.
A cluster often appears suddenly, lasts around an hour, then disappears suddenly.
During an attack, or cluster period, headaches happen frequently. During remission, the pain does not occur.
There are a number of treatment options for cluster headaches.
There is no cure for cluster headaches, but drugs, such as sumatriptan, and other treatments, including oxygen therapy, can help reduce the incidence and severity of attacks.
Treatment aims to relieve some of the symptoms, shorten the periods of headaches, and reduce their frequency.
Over-the-counter (OTC) painkillers, such as aspirin or ibuprofen, are not effective, because the pain starts and finishes so rapidly that by the time the medication starts to work, the headache has probably gone.
Medications and treatments for cluster headaches aim either to prevent them or to act quickly.
Treatments that can provide rapid relief include:
Inhaling 100-percent oxygen: Breathing in oxygen through a mask at 7 to 10 liters per minute may bring significant relief within 15 minutes. It is not always practical to have an oxygen cylinder and regulator close at hand, but some small units are available. Oxygen therapy may only postpone symptoms, rather than alleviating them.
Injectable sumatriptan (Imitrex): Triptans are a class of drug that can treat migraines. Sumatriptan acts as an agonist for 5-hydroxytryptamine (5-HT) receptors. It can treat migraines, and it can bring rapid relief from cluster headaches. Zolmitriptan (Zomig) is a nasal spray, but it only works for some patients. The adult dose is a 6-milligram (mg) injection. Two injections can be taken in one 24-hour period, at least one hour apart.
People with uncontrolled hypertension (high blood pressure) or ischemic heart disease should not take this drug.
Dihydroergotamine: This is an effective pain reliever for some people. It can be taken intravenously or inhaled. A medical professional will need to give an intravenous dose. The inhaler form is effective but less fast-acting.
Octreotide (Sandostatin, Sandostatin LAR): These are synthetic versions of somatostatin, a brain hormone. It is injected. It is an effective treatment for cluster headaches and considered safe for those with hypertension or ischemic heart disease.
Local anesthetic nasal drops: Lidocaine (Xylocaine) is an effective treatment for cluster headaches.
Surgery: This may be an option if drug treatments do not work, or if the person cannot tolerate the medications. However, this is rare. It can only be performed once, and it is only suitable for those with pain on just one side of the head.
Surgical procedures include:
Conventional surgery: The surgeon cut part of the trigeminal nerve, which serves the area behind and around the eye. There are risks of damage to the eye.
Glycerol injection: Glycerol is injected into the facial nerves. This effective treatment is safer than other surgical procedures.
Possible future treatments
Some new treatment options are being investigated.
Occipital nerve stimulation: A small device is implanted over the occipital nerve. It sends impulses via electrodes. It appears to be well tolerated and safe to use.
Deep brain stimulation: This would involve implanting a stimulator in the hypothalamus, which appears to be linked to the timing of cluster headaches. This would change the electrical impulses in the brain.
Treatments that target the hypothalamus are considered by some researchers to be the most likely to succeed, and deep brain stimulation has been described as “at present the most attractive option” for patients who do not respond to other treatments.
However, further studies are needed to confirm its safety and effectiveness.
Most people with cluster headaches take short- and long-term medications. When each period of clusters is over, the short-term treatments stop, but the long-term ones may continue.
If attacks occur frequently, or if one lasts over 3 weeks, preventive treatments are recommended. The person will take the treatment the moment the headaches start, and continue until the period of headaches ends.
These are taken until one of the long-term medications start working.
Corticosteroids: These steroids, such as Prednisone, suppress inflammation. They are a fast-acting, preventive drug that can help those with new symptoms or those who have long periods of remission and short cluster periods.
Ergotamine (Ergomar): This temporarily narrows blood vessels throughout the body. It is taken at night before going to bed, either under the tongue or as a rectal suppository. Ergotamine cannot be taken with triptans. It should not be used for long periods, or if the person has poor circulation.
Anesthetic on the occipital nerve: Injecting anesthetic can numb this nerve, which is located at the back of the head. As a result, pain messages that travel along the nerve pathway are blocked. This treatment is stopped as soon as a long-term preventative medication starts to work.
Long-term drugs are taken throughout the cluster period. Some people may need more than one long-term medication.
Calcium channel blockers, such as verapamil (Calan, Verelan): These are taken during the cluster period and then gradually tapered off, although some people may need to use them long term. Side effects include constipation, nausea, tiredness, swollen ankles, low blood pressure (hypotension), and dizziness. If the dose is increased, regular heart monitoring will be needed.
Lithium carbonate, for example, lithium (Lithobid, Eskalith): Used to treat bipolar disorder, it is also effective in preventing chronic cluster headaches. Side effects include increased urination, diarrhea, and tremor. The intensity of side effects is usually linked to dosage, which the doctor can alter. Regular blood tests will check for possible kidney damage.
Anti-seizure medications, such as divalproex (Depakote) and topiramate (Topamax), are also effective long-term treatments for cluster headaches.
Cluster headaches usually affect only one side of the head.
Symptoms include intense pain that starts rapidly, usually without warning. Pain is continuous rather than throbbing. It has been described as stabbing, sharp, burning, and penetrating.
It often starts around the eye, and it may then radiate to other parts of the head, including the face, neck, and shoulders. Pain may be present in a temple or a cheek. It remains on one side of the head.
There may also be:
redness, swelling, watering in the eye on the side of the pain
stuffy, blocked, or runny nose on the pain side
small pupil size
drooping of the eyelid on the pain side