An Overview of Cluster Headaches

Cluster headaches are characterized by sudden bouts of recurrent, severe head pain that occur every day (or nearly every day) for weeks, months, or even years. The pain associated with this condition is intense and located on one side of the head. The head pain is often accompanied by red or inflamed eyes and nasal discharge. Most people have periods of remission without attacks that last from months to years.

This type of headache is relatively rare, affecting between 0.1 and 0.3% of the population. It is most common between ages 20 to 40 and men are twice as likely as women to experience cluster headaches.

Symptoms

Cluster headaches arise as severe pain in one side of the head, usually starting around one eye, before spreading to the temples and face. The intensity of this pain is described as very severe burning, poking, or piercing (as opposed to throbbing).

This may be accompanied by additional symptoms, including:

• Flushed face and sweating
• Redness and inflammation in the affected eye
• Tearing
• Drooping of the affected eyelid
• Pupil constriction
• Runny or stuffed-up nose
• Facial swelling
• Restlessness and inability to sit still or lie down

The duration of the headache is usually 15 to 30 minutes and it can last for up to three hours. Attacks tend to group together, and you can experience one to eight periods of pain a day.

Cluster headaches tend to occur at consistent times of day—oftentimes at night—and are often seasonal, more commonly arising in the spring or fall. Cluster cycles are interspersed with periods of remission, which can last from less than a month to several years. 

Causes

The direct cause of a cluster headache is dilation of vessels, which puts pressure on the trigeminal nerve, a nerve associated with facial sensation and movement. Cluster headache is a primary headache disorder, which means that the reason it occurs is unknown.

Cluster headache is the most common of a group of disorders called “trigeminal autonomic cephalalgias." The autonomic nervous system, which controls involuntary activities of the body, such as pupil size, is involved in cluster headaches. Researchers have also observed altered activity in the hypothalamus, which is an area of the brain that's associated with regulating sleep-wake cycles and biological rhythm.

Triggers aren’t as prevalent with cluster headaches as they are with migraines or other headache types.

There are a number of risk factors for the condition:

• Smoking tobacco
• Alcohol consumption
• Age between 20 to 40
• Men are twice as likely as women to develop the condition
• Family history

Diagnosis

Proper diagnosis of this condition isn’t easy as there’s no singular test for it. What’s even more challenging is that cluster headaches can easily be mistaken for migraines. Still, diagnostic criteria are established by the International Classification of Headache Disorders.

A patient is determined to have cluster headaches if they experience at least five attacks characterized by one of the following:

• Severe pain on one side of the head
• Headache accompanied by at least one of the other symptoms of the condition
• A frequency of attack of one every other day to up to eight a day

Treatment

Treatment of cluster headaches is usually an individualized process, and what works for one person may not for another. If you smoke, it's important that you stop smoking, because smoking can contribute to the severity and frequency of cluster headaches.

Broadly speaking, treatments can be divided into acute treatments you can use during an attack and preventative treatments that are used to reduce the frequency and severity of attacks.

Acute treatment approaches include:

• Oxygen: A common approach taken on in the hospital involves the delivery of pure oxygen via mask with an oxygen tank. When treated this way, dramatic reductions in symptoms are seen within 15 minutes.
• Triptans: This pharmaceutical drug class is a common treatment for both cluster and migraine headaches. For treatment of cluster headaches, sumatriptan is can be injected by a healthcare provider or you can use it in a nasal spray form. Another type, zolmitriptan, is available as a nasal spray. 
• Octreotide: The idea behind the injection of octreotide is that it mimics the brain chemical somatostatin. While generally not as effective as triptans, this approach works very well in some cases.
• Local Anesthetic: Local anesthetics such as lidocaine, usually delivered through the nose, can also put a stop to pain.  
• Dihydroergotamine: Another medication that’s also used in migraine treatment, dihydroergotamine, when injected, is known to be effective in relieving the symptoms of cluster headaches.  

There are also a number of preventative approaches to this condition; these are used on a regular daily basis, even when you aren't having symptoms.

Preventative treatments include:

• Calcium Channel Blockers: These medications prevent calcium from causing contraction of the muscles in the blood vessels. They allow the blood vessels to relax, reducing blood pressure. Calcium channel blocking drugs like Calan, Verelan, and others can help prevent cluster headaches for some people. 
• Corticosteroids: This class of drug reduces inflammation and can help reduce the frequency and severity of cluster headaches for some people.
• Lithium Carbonate: Although it's a common approach to treating bipolar disorders, lithium carbonate may be prescribed for preventing cluster headaches.
• Nerve Block: The targeted delivery of local anesthetic combined with a corticosteroid in the area around the occipital nerve (towards the back of the head) is sometimes used to combat difficult, chronic cases of cluster headaches.
• Emgality: In 2019, the FDA approved the injection of a migraine-preventing medication—Emgality—for cluster headache. 

For chronic cluster headaches or cluster headaches that don't improve with medication, surgeries or other interventions may be considered. The stimulation of certain brain regions, for instance, can help reduce headache pain. This involves the use of electrodes called neurostimulators in either the sphenopalatine ganglion (a cluster of nerves linked to the trigeminal nerve often at the core of pain) or the vagus nerve in the neck. Though effective, these approaches are invasive and have a chance of side effects. 

Coping

The fact that headaches aren’t visible makes it difficult for family, friends, and coworkers to understand the severity of what you're experiencing.

Cluster headaches can affect work attendance or work performance, for instance. This being the case, it may be helpful to discuss your condition with your managers and colleagues.  

Consider discussing your concerns and feelings with a qualified therapist, who may be able to help you manage your expectations and cope with the effects of your condition.

A Word From Verywell

The intensity and severity of cluster headaches should not be underestimated. If you have been diagnosed with this condition, don’t suffer in silence; treatments are available. Your health is important, and you owe it to yourself and those around you to get help when you need it.