What is it?
Cluster headache is a type of headache set apart by its severity and its pattern. The pain is always on one side of the head and gathers in and behind the eye; it spreads to the temple, the upper jaw and the upper back teeth. An untreated attack lasts between fifteen minutes and three hours and then settles on its own.
Autonomic findings are seen on the painful side: a red, watering eye, a drooping or swollen eyelid, a blocked or running nose, and sweating on the forehead and face. Attacks return at certain times of day, often waking you from sleep at night.
There is one clear difference in behaviour from migraine: during a migraine attack you want to lie still, while during a cluster attack you cannot keep still, you pace about and feel agitated. Because the pain is felt in the upper back teeth, the first visit may be to a dentist, and dental treatments that lead nowhere can end up being started.
Signs
You will not necessarily have all of these at once.
Why does it happen?
- 01
The body clock being thrown off
Attacks gathering at the same time of day and in certain seasons of the year suggests that the part of the brain governing the sleep and waking rhythm takes part in the process. This regularity is one of the most typical features of the condition.
- 02
Trigeminal and autonomic pathways being triggered together
The nerve carrying sensation from the face and the nerve fibres governing tears, nasal secretion and the eyelid sit in the same reflex loop. That loop switching on explains why the pain and the eye and nose findings appear together.
- 03
Alcohol and smoking during a cluster period
Alcohol taken while a cluster period is running can start an attack within a short time. The same person may not see this effect during remission. Smoking is markedly common in these patients.
- 04
A disturbed sleep pattern
Broken night sleep, travel across time zones and changes of shift can make attacks more frequent. Attacks often appear during particular stages of sleep.
How does it progress?
- Attack
A single attack
One-sided pain that climbs within minutes to a level that is hard to bear lasts, along with the eye and nose findings, between fifteen minutes and three hours.
- Cluster
The cluster period
This is the period when attacks repeat for weeks or months, often once or several times a day. The attacks stay on the same side throughout this period.
- Break
Remission
The cluster period ends and there are no attacks at all for months, sometimes years. You are completely free of pain during this time, and triggers such as alcohol may not show their effect.
- Chronic
The chronic form
In one group of people the attacks carry on for longer than a year with no long pain-free stretch in between. This form calls for closer follow-up.
How is it treated?
For this condition the place to go is a neurology clinic, if possible one with a unit that works on headache. Cluster headache is not treated in dentistry. Taking a written note of how long the attack lasts, what time of day it comes and what the eye and nose findings are will speed up the diagnosis.
What to expect at neurology is a detailed history and the ruling out of other causes that can look similar; brain imaging may be requested for that purpose. Treatment runs along two lines: measures aimed at stopping an attack quickly, and preventive treatment aimed at reducing attacks through the cluster period. The choice of method and how long it runs are the doctor's decision.
The dentist's role is to notice this picture and refer you on. In a patient describing pain in the upper back teeth, the teeth are assessed by their vitality, their response to biting and radiographs. If there is no cause belonging to a tooth, root canal treatment or extraction is not carried out. Pain that builds within minutes and settles on its own within a few hours, with eye findings on the same side, is a pattern that does not fit tooth-related pain.
- A headache of a severity you have never known before that starts suddenly
- A drooping eyelid or a difference in pupil size that carries on after the attack has ended
- Vision becoming disturbed or double vision along with the pain
- Fever, a stiff neck or a change in consciousness coming with it
How is it prevented?
- Stay away from alcohol while a cluster period is running; even small amounts can start an attack during this time.
- Keep the times you sleep and wake steady and avoid long naps during the day.
- Note the time, the length and the side of your attacks; this record has a direct effect on the doctor's plan.
- Do not stop the preventive treatment your doctor has given you on your own decision because the attacks have eased.
Frequently asked questions
- The pain is in my upper teeth, can it really not be coming from a tooth?
- It may be and it may not; examination is what tells them apart. Tooth-related pain is usually linked to heat, cold or biting and can last for hours. A cluster attack starts with no trigger, peaks within minutes, makes the eye on the same side red and the nose blocked, and settles on its own within a few hours.
- The attack passes in half an hour, should I still see a doctor?
- Yes. A short attack does not mean the condition is mild; cluster headache can repeat several times a day, and suitable treatment cannot be planned without the right diagnosis. Other causes that look similar also need to be ruled out, and neurology carries out that assessment.
- Is this pain a severe form of migraine?
- No, it is a separate condition. A migraine attack lasts for hours, you want to stay still, and nausea and sensitivity to light come first. A cluster attack is shorter, produces eye and nose findings on the same side, and leaves you agitated and pacing about. The treatment approaches differ as well.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.