What is a Cluster Headache?
Cluster Headaches
Cluster headache is a rare but severe headache disorder that is very different from other types of headache. Attacks often come on without warning and cause intense, sharp or burning pain around or behind one eye. Many people describe it as the worst pain they’ve ever felt.
During a cluster period, people may have from one attack every other day to as many as eight attacks a day, often at the same times of day, for weeks or months. These periods are usually followed by remission periods with no headaches that can last months or even years. Unfortunately, cluster periods often return.
If you have a sudden, severe headache that feels like the worst of your life, or a headache with weakness, numbness, confusion, trouble speaking, a stiff neck or fever, call 911 or get emergency care. Cluster headache pain can be overwhelming. If you are having thoughts of harming yourself, call or text 988 to reach the 988 Suicide & Crisis Lifeline.
How Common Are Cluster Headaches?
Cluster headaches are rare, affecting about 1 in every 1,000 people. They are more common in men than in women. Cluster headaches also appear to run in families: close relatives of someone with cluster headaches have a 5 to 18 times higher risk than the general population (1).
What Causes Cluster Headaches?
The exact cause of cluster headaches isn’t known. They appear to involve abnormal activation of the trigeminovascular system, a network of brainstem nerve cells and the blood vessels they connect to.
The trigeminal nerve carries pain signals from the head, face, the blood vessels of the brain and the upper neck. In cluster headaches, the first branch of the trigeminal nerve, called V1, becomes abnormally active. This branch carries pain from around and behind the eye. What triggers this activation isn’t well understood (2).
During a cluster period, alcohol can trigger attacks. Many people with cluster headaches have a history of smoking, but quitting after cluster headaches begin doesn’t seem to stop them (1).
Cluster headaches also activate a reflex called the trigeminal-autonomic reflex, which switches on part of the parasympathetic nervous system. This causes symptoms such as a watery eye, a stuffy nose and facial sweating on the side of the pain (2).
What Are the Symptoms of Cluster Headaches?
Cluster headaches cause episodes of intense, sharp pain around or behind one eye. The pain can spread across that side of the face and into the head and neck. On the same side, there may also be heavy tearing, swelling, pale skin, sweating and a drooping eyelid. Many people feel restless or agitated during an attack and can’t sit still. Nausea, light sensitivity and other migraine-like symptoms can also occur (3).
How Are Cluster Headaches Diagnosed?
Cluster headache is diagnosed by a healthcare provider based on your history and exam. International criteria require at least five attacks with:
Severe pain on one side, around or above the eye or at the temple, lasting 15 to 180 minutes if untreated.
At least one of the following on the same side as the pain: a watery or red eye, a stuffy or runny nose, eyelid swelling, forehead and facial sweating or flushing, a feeling of fullness in the ear, or a small pupil and drooping eyelid. A sense of restlessness or agitation can also count.
Attacks happening anywhere from once every other day to eight times a day for more than half the time the disorder is active.
Episodic cluster headache means attacks happen in periods lasting 7 days to 1 year, separated by pain-free periods of at least 3 months. Chronic cluster headache, the most difficult form, means attacks happen for a year or more without a break, or with breaks shorter than 3 months.
How Do Cluster Headaches Affect Your Life?
Cluster headaches can place a heavy burden on daily life. They can affect employment, since the pain is so severe that working during an attack is often impossible (4). People with cluster headaches also tend to have higher rates of depression and anxiety, and are more likely to struggle with substance use (5).
What Happens in the Brain With Cluster Headaches?
Pain signals from the head, face, upper neck, the membranes around the brain (the meninges) and the brain’s blood vessels travel into the brainstem through the trigeminal nerve. The trigeminovascular pathway is made up of nerve cells that supply the brain’s blood vessels and meninges. Their cell bodies sit in a cluster called the trigeminal ganglion.
These nerve fibers connect to an area called the trigeminocervical complex, which also receives pain input from the upper neck, the jaw joints and the skin of the head and face.
The trigeminocervical complex sends pain signals up to the thalamus, which activates the brain areas that process pain.
The nerve cells of the trigeminal ganglion contain chemicals that widen blood vessels, including one called CGRP. CGRP levels rise during cluster headache attacks as the trigeminovascular pathway is activated (6).
The watery eye, runny nose and stuffy nose seen in cluster headaches come from the trigeminal-autonomic reflex, which widens blood vessels and activates the parasympathetic nervous system.
Cluster periods often follow a seasonal pattern and may occur around the same times each year, sometimes around the time changes for daylight saving time. This is likely linked to changes in day length and involves the brain’s internal clock, which includes the hypothalamus and the suprachiasmatic nucleus.
Melatonin is a hormone made by the pineal gland that helps regulate your sleep-wake cycle. Light lowers melatonin, and darkness raises it. In people with episodic cluster headaches, melatonin levels have been found to be lower during cluster periods, which may be linked to the sleep problems that come with these headaches (7).
Oxygen also seems to play a role. Research suggests that oxygen affects the nerve fibers that connect the parasympathetic system to the brain’s blood vessels, and that breathing high-flow oxygen can calm the trigeminovascular and autonomic activity involved in an attack (8).
How Are Cluster Headaches Usually Treated?
Cluster headaches are diagnosed and treated by physicians and other medical providers. Common treatments include triptan medications and breathing high-flow oxygen through a mask during an attack, both prescribed by a medical provider, along with preventive medications. When these don’t work well enough, other options may include nerve block injections and, in some cases, surgery (9).
How the NeuroRescue Program Can Help
Our care is designed to work alongside your physician, neurologist and other providers, never in place of them. Please continue the treatments your medical providers have prescribed, and don’t change or stop any medication without talking with your prescriber.
Non-invasive neuromodulation, which uses gentle electrical or magnetic stimulation from outside the body, is an emerging area of research for cluster headaches. Approaches that have been studied include electrical stimulation of the vagus nerve or the supraorbital nerve above the eye, and transcranial magnetic stimulation (TMS) (10, 11).
Because abnormal activation of the trigeminovascular system is believed to drive cluster headaches, your program may include gentle stimulation of the supraorbital nerve and other branches of the trigeminal nerve, with the goal of helping calm activity in this system.
Research suggests that migraine and cluster headaches may share some of the same trigeminovascular pathways (12). Some approaches that have been studied for migraine, such as vestibular rehabilitation (13), may also be considered as part of your care, although research in cluster headaches specifically is limited.
Your program may also include transcutaneous vagus nerve stimulation (tVNS), which uses gentle electrical stimulation on the skin. The vagus nerve is a major part of the parasympathetic nervous system, which helps the body relax and recover. Research on non-invasive vagus nerve stimulation in episodic and chronic cluster headache has shown encouraging results (14).
At our clinic, TMS is provided by our psychiatric mental health nurse practitioner, who will evaluate whether it may be appropriate for you.
We also evaluate the muscles, joints, ligaments and nerves of your neck and jaw, which send pain input into the trigeminal system, along with the brain and brainstem systems that normally calm pain. Your program may include care for your neck and jaw, including chiropractic adjustments when appropriate. The therapies we recommend are always chosen based on your testing and exam findings.
How the NeuroRescue Program Works
Your NeuroRescue Program begins with your Discovery Day. We start with a detailed history of your condition and your life on a timeline. This helps us understand the factors that may have contributed to where you are now, and identify related conditions that may be making it harder to move forward.
We measure how your visual, vestibular and balance systems are working through computerized analysis of your eye movements, inner ear reflexes and balance under different conditions. Our testing includes videonystagmography and saccadometry to measure several types of eye movements, the video head impulse test to measure inner ear reflexes, and CAPS computerized posturography to assess your balance under different sensory conditions. We also use NeuroSensoryMotor Integration testing to evaluate hand-eye coordination and cognition, and Virtualis testing to assess dynamic eye tracking and your perception of vertical in a virtual reality environment.
We combine this with a thorough physical and neurological exam of your sensory, motor, autonomic and cognitive systems. We also review any relevant lab work, imaging and prior testing, and integrate it with our findings.
Together, this helps us understand which parts of your nervous system are working well, which are struggling, and how quickly they tire. We use that information to design your personal NeuroRescue Program, aimed at improving function in the systems that need support and helping them work together. Our testing also helps us decide when to push and when to let you rest.
Our goal is to support your medical care and help you feel more in control of your life, during cluster periods and between them.
Your Next Step
Living with cluster headaches can be exhausting and frightening, but you don’t have to face them alone. To find out if the NeuroRescue Program is right for you, contact one of our patient care coordinators to schedule your Discovery Day.
It’s never too late to take the next step.
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