Cluster headache (Bing-Horton neuralgia) is a severe primary headache disorder that exceeds even migraine attacks in pain intensity. The pain is usually felt in attacks around the eyes. Also typical is the periodic occurrence: Acute pain attacks, which can last for several weeks or months (cluster period), alternate with headache-free phases (remission phase). Although the exact cause of cluster headache has not yet been clarified, some trigger factors such as alcohol or heat are known. Both preventive and acute therapeutic treatment options are available to alleviate the symptoms of affected patients.
Cluster headache: symptoms
Cluster headaches begin suddenly and usually affect only one side of the face. They usually occur around one eye, but can also radiate toward the root of the nose, jaw, temple, forehead, and neck. The pain is described by some sufferers as a “red-hot knife in the eye” and is also referred to as a “suicidal headache” because of its severity. The duration of a pain attack can range from fifteen minutes to three hours. The frequency of attacks ranges from one attack every other day to eight attacks daily. Cluster headaches are often accompanied by the following symptoms:
- Eye tearing and eye redness
- Pupil constriction
- Eyelid swelling and drooping eyelid
- Nasal mucous membrane swelling
- Sweating in the area of the face
- Dizziness and nausea
- Physical restlessness and strong urge to move
In our experience, the headaches always occur at the same time of day: Most often they are noticeable one to two hours after falling asleep or in the early morning hours. In addition, seasonal clusters of active cluster periods are evident in spring and autumn.
Epidemiology of cluster headache
Cluster headaches are relatively rare compared with other types of headache: Less than one percent of the population is affected, whereas about ten percent suffer from migraine. The headaches occur mainly in young men between the ages of 20 and 40. Why men are affected around three times more often than women has not yet been clarified.
Episodic and chronic course
Cluster headaches can occur in an episodic or a chronic form. In an episodic course, periods of symptoms last from at least a week to more than a year. In between, there are always symptom-free intervals of at least one month. In contrast, chronic cluster headaches occur when the headache attacks last longer than a year without improvement, there are no symptom-free breaks or they are shorter than four weeks. About 80 percent of sufferers have an episodic course and 20 percent have a chronic course.
Causes and heredity
The exact causes of cluster headache have not yet been determined. However, the fact that the headache is associated with a dilation of inflamed blood vessels in the brain is now ruled out. Rather, scientists suspect that a biological rhythm disturbance could cause the development of cluster headaches. The hypothalamus plays a central role in this. The hypothalamus forms part of the diencephalon and regulates not only body temperature, circulation and food intake but also the biological day-night rhythm. This assumption is supported by the fact that cluster attacks occur at different times of the day or year. Some studies show that heredity also plays a role in the occurrence of cluster headaches: In first-degree relatives, the headache occurs up to 18 times more frequently and in second-degree relatives one to three times more frequently than in the normal population. However, the exact inheritance factors are not known.
Triggers of cluster headache
During the active cluster period, certain internal and external stimuli, known as triggers, can trigger a cluster attack in some individuals. Known triggers include alcohol, histamine, and nitroglycerin. In the case of alcohol, paradoxically, small amounts can provoke a cluster attack, while larger amounts can partially prevent an attack. The substance histamine is contained, for example, in strawberries, tomatoes, chocolate or red wine.Nitroglycerin, which is used in medications as an active ingredient to expand blood vessels, can also promote cluster attacks. Other provoking factors include:
- Nicotine
- Flickering light
- Noise
- Extreme heat
- Changes in altitude
- Physical stress
However, such triggers can only trigger attacks during cluster periods; they are ineffective during remission periods.
Diagnosis of headache disorder
Cluster headache is a disorder that is diagnosed on the basis of symptoms alone. Imaging techniques are useful at best to rule out other causes of the complaints. The collection of the medical history and the occurring symptoms are therefore the central means for diagnosis. For this reason, it makes sense to keep a headache diary for all recurring headaches. This facilitates the diagnosis for the physician, serves to monitor the therapy and can help to identify possible triggers. Photographs taken of the patient’s face during an attack can also be important for diagnosis. On average, it takes five to seven years before a definitive diagnosis is made.
The nitroglycerin provocation test.
The nitroglycerin provocation test provides a method to confirm the diagnosis of cluster headache. However, this method is ethically controversial and is rarely practiced nowadays. The test involves intentionally inducing a headache attack during a cluster period by administering nitroglycerin. However, this only works if no spontaneous attack has occurred within the past eight hours, no vasodilator substances have been taken within the past 24 hours, and no drug prophylaxis is being used.
Treating cluster headaches
When treating cluster headaches, conventional pain medications with active ingredients such as acetylsalicylic acid, ibuprofen, or diclofenac are not effective. Alternative therapies such as acupuncture or massage also show no effect. Basically, the most important thing is to avoid triggers (for example, alcohol, histamine, and nitroglycerin) during the cluster period. In the treatment of cluster headaches, a general distinction is made between therapy of the acute single attack and preventive measures.
Acute therapy: what helps?
In acute therapy, the administration of 100 percent oxygen has proven to be extremely effective. This involves delivering eight to 16 liters of oxygen per minute to the affected person for 15 to 20 minutes through a high-concentration mask. Inhalation of pure oxygen ends the cluster headache attack within a short time in almost 80 percent of cases and is also free of side effects. Its use at the beginning of an attack is particularly effective. Furthermore, treatment with lidocaine, a local anesthetic, has proven effective. The substance is either given into the nostril of the affected side of the headache or injected near a nerve pathway to cause a nerve block. The drug sumatriptan is also used for the acute treatment of cluster headaches. Sumatriptan interferes with the metabolism of serotonin, a key neurotransmitter in pain processing. However, unpleasant side effects such as dizziness, fatigue, or a drop in blood pressure may occur when taking sumatriptan.
Preventing cluster headaches
For preventive therapy, corticosteroids are preferred for both episodic and chronic cluster headaches, as is the active ingredient verapamil. Lithium is also suitable for the treatment of cluster headache. However, its use is occasionally associated with side effects such as weight gain, poor concentration, or increased urination. In drug therapy, it is important to ensure that the drugs used for acute therapy and prophylaxis are compatible with each other and can be combined. Although there is no cure for cluster headache to date, the quality of life of affected patients can be significantly improved by avoiding trigger factors and by targeted therapy.
