A cluster headache is one of the most painful types of headache. A
striking feature of cluster headache is that the attacks occur in
cyclical patterns, or clusters — which gives the condition its name.
Bouts of frequent attacks — known as cluster periods — may last from
weeks to months, usually followed by remission periods when the headache
attacks stop completely. The pattern varies from one person to another,
but most people have one or two cluster periods a year. During
remission, no headaches occur for months, and sometimes even years.
Fortunately, cluster headache is rare and not life-threatening.
Treatments can help make the attacks shorter and less severe. In
addition, preventive medications can help reduce the number of
A cluster headache strikes quickly, usually without warning. Typical signs and symptoms include:
* Excruciating pain, generally located in or around the eye, but may
radiate to other areas of the face, head, neck and shoulders
* One-sided pain
* Excessive tearing
* Redness in the eye of the affected side
* Stuffy or runny nasal passage in the nostril on the affected side of your face
* Sweaty, pale skin (pallor) on the face
* Swelling around the eye on the affected side of your face
* Reduced pupil size
* Drooping eyelid
The pain of a cluster headache is often described as sharp, penetrating
or burning. People with this condition say that the pain feels like a
hot poker being stuck in the eye or that the eye is being pushed out of
its socket. People with cluster headache appear restless, preferring to
pace or sit and rock back and forth to soothe the attack. In contrast to
people with migraine, people with cluster headache usually avoid lying
down during an attack because this position seems to increase the pain.
Some migraine-like symptoms, including nausea, sensitivity to light and sound, and aura, may occur with a cluster headache.
Cluster period characteristics
A cluster period generally lasts from one to 12 weeks. The starting date
and the duration of each cluster period may be consistent from period
to period. For example, cluster periods occur seasonally, such as every
spring or every fall.
Most people have episodic cluster headaches, which means the cluster
headaches occur for one week to a year, followed by a pain-free
remission period that may last as long as six to 12 months before
another cluster headache develops. Chronic cluster periods may continue
for more than a year, or pain-free periods may last less than one month.
During a cluster period:
* Headaches typically occur every day, sometimes several times a day.
* A single attack may last from 15 minutes to three hours.
* The attacks happen often at the same time within each 24-hour day.
* The majority of attacks occur between 9 p.m. and 9 a.m.
The pain usually ends as suddenly as it begins, with rapidly decreasing
intensity. After attacks, most people are completely free from pain but
When to see a doctor
If you've just started to experience cluster headaches, see your doctor
to rule out other disorders and to find the most effective treatment.
Headache pain, even when severe, usually isn't the result of an
underlying disease, but headaches may occasionally indicate a serious
underlying medical condition, such as a brain tumor or rupture of a
weakened blood vessel (aneurysm). Additionally, if you have a history of
headaches, see your doctor if the pattern changes or your headaches
suddenly feel different.
See your doctor or go to the emergency room immediately if you have any of these signs and symptoms:
* Abrupt, severe headache, often like a thunderclap
* Headache with a fever, stiff neck, mental confusion, seizures,
numbness or speaking difficulties, which may indicate a number of
problems, including stroke, meningitis, encephalitis or brain tumor
* Headache after a head injury, even if it's a minor fall or bump, especially if it gets worse
* A sudden, severe headache unlike any other headache you've experienced.
The exact cause of cluster headaches is unknown, but abnormalities in
the hypothalamus likely play a role. Cluster attacks typically occur
with clocklike regularity during a 24-hour day, and the cycle of cluster
periods often follows the seasons of the year. These patterns suggest
that the body's biological clock is involved. In humans, the biological
clock is located in the hypothalamus, which lies deep in the center of
your brain. Abnormalities of the hypothalamus may explain the timing and
cyclical nature of cluster headache. Studies have detected increased
activity in the hypothalamus during the course of a cluster headache.
Other factors that may be involved in the development of cluster headaches include:
* Hormones. People who have cluster headaches have abnormal levels
of certain hormones, such as melatonin and cortisol, during cluster
* Neurotransmitters. Changes in the levels of some of the chemicals
that carry impulses in the brain (neurotransmitters), such as serotonin,
may play a role in the development of cluster headaches.
Unlike migraine and tension headache, cluster headache generally isn't
associated with triggers such as foods, hormonal changes or stress. But
once a cluster period begins, consumption of any alcohol can quickly
trigger a splitting headache. For this reason, many people with cluster
headache avoid alcohol for the duration of a cluster period. Other
possible triggers include the use of medications such as nitroglycerin, a
drug used to treat heart disease.
Risk factors for cluster headaches include:
* Being a man. Men are more likely than are women to have cluster headaches.
* Being an adult. Most people with cluster headaches first develop
the disorder in their late 20s, although the condition can develop at
* Being black. Blacks are more likely than whites to experience cluster headaches.
* Smoking. Many people who get cluster headache attacks are smokers.
* Drinking alcohol. Alcohol can trigger an attack if you're at risk of cluster headache.
* A family history. If a parent or sibling has ever had a cluster
headache, you may have an increased risk of cluster headaches.
Preparing for your appointment
You're likely to start by first seeing your family doctor. However, you
may be referred immediately to a neurologist, a doctor who specializes
in treating nervous system disorders, such as headache.
Because appointments can be brief, and there's often a lot of ground to
cover, it's a good idea to be well prepared for your appointment. Here's
some information to help you get ready for your appointment, and what
to expect from your doctor.
What you can do
* Write down any symptoms you're experiencing, including any that
may seem unrelated to the reason for which you scheduled the
appointment. Try to keep track of when you have a headache, how long it
lasts, and what you were doing when the headache started.
* Write down key personal information, including any major stresses or recent life changes.
* Make a list of all medications, as well as any vitamins or
supplements, that you're taking, and share this information with your
* Write down questions to ask your doctor.
Your time with your doctor is limited, so preparing a list of questions
may help you make the most of your time together. List your questions
from most important to least important in case time runs out. For
cluster headaches, some basic questions to ask your doctor include:
* What's the most likely cause of my symptoms?
* Are there other possible causes for my symptoms?
* What kinds of tests do I need? What will these tests rule out?
* Is my condition likely temporary or chronic?
* What treatments are available? Which do you recommend?
* What are the alternatives to the primary approach that you're suggesting?
* I have these other health conditions. How can I best manage them together?
* Are there any restrictions that I need to follow?
* Do I need to see a specialist?
* Is there a generic alternative to the medicine you're prescribing me?
* What are common side effects to the medications you're prescribing?
* Are there any brochures or other printed material that I can take home with me? What Web sites do you recommend?
In addition to the questions that you've prepared to ask your doctor,
don't hesitate to ask questions during your appointment if you don't
What to expect from your doctor
Your doctor will likely ask you a number of questions. Being ready to
answer them may reserve time to go over any points you want to spend
more time on later. Your doctor may ask:
* When did you first begin experiencing symptoms?
* Have your symptoms been continuous, or occasional?
* Do your symptoms tend to occur at the same time of day? Do they occur during the same season each year?
* Does alcohol appear to cause your symptoms?
* How severe are your symptoms?
* What, if anything, seems to improve your symptoms?
* What, if anything, appears to worsen your symptoms?
Tests and diagnosis
Cluster headache has a characteristic type of pain and pattern of
attacks. A diagnosis depends on your description of the attacks,
including your pain, the location and severity of your headaches, and
associated symptoms. The frequency and duration of your headaches also
are important factors.
If you have chronic or recurrent headaches, your doctor may try to
pinpoint the type and cause of your headache using certain approaches.
Examinations and tests
* Neurological examination. A neurological examination may help your
doctor detect physical signs of a cluster headache. Sometimes the pupil
of your eye may appear smaller, or your eyelid may droop, even between
* Imaging tests. If you have unusual or complicated headaches or an
abnormal neurological exam, you may undergo other diagnostic testing to
rule out other serious causes of head pain, such as a tumor or aneurysm.
Two common brain-imaging tests are computerized tomography (CT) and
magnetic resonance imaging (MRI) scans. A CT scan uses a series of
computer-directed X-rays to provide a comprehensive view of your brain.
An MRI doesn't use X-rays. Instead, it combines magnetism, radio waves
and computer technology to produce clear images of your brain.
One of the most helpful things you can do is keep a headache journal for
at least two months. Each time you get a headache, jot down the
* A description of the pain
* The severity of the pain
* The location of the pain
* The duration of the pain
* Any medications you're taking
* The time
* What you were doing
* What you were eating or drinking
A headache journal can offer valuable clues that may help your doctor
diagnose your particular kind of headache and discover possible headache
Treatments and drugs
There's no cure for cluster headaches. The goal of treatment is to help
decrease the severity of pain and shorten the headache period.
Because the pain of a cluster headache comes on suddenly and may subside
within a short time, over-the-counter pain relievers such as aspirin or
ibuprofen (Advil, Motrin, others) aren't effective. The headache is
usually gone before the drug starts working. Fortunately, other types of
acute medication can provide some pain relief. Treatment of cluster
headache is focused more on prevention, with more medication options
available to choose from.
Fast-acting treatments available from your doctor include:
* Oxygen. Briefly inhaling 100 percent oxygen through a mask at a
rate of 7 to 10 liters a minute provides dramatic relief for most who
use it. The effects of this safe, inexpensive procedure can be felt
within 15 minutes. The major drawback of oxygen is the need to carry an
oxygen cylinder and regulator with you, which can make the treatment
inconvenient and inaccessible at times. Small, portable units are
available, but some people still find them impractical. Sometimes,
oxygen may only delay rather than stop the attack, and pain may return.
Triptans. The injectable form of sumatriptan (Imitrex), which is
commonly used to treat migraine, also is an effective acute treatment
for cluster headache. Some people may benefit from using sumatriptan in
nasal spray form, but for most people this isn't as effective as an
injection. Sumatriptan isn't recommended if you have uncontrolled high
blood pressure or ischemic heart disease.
Another triptan medication, zolmitriptan (Zomig), can be taken in
nasal spray form for relief of cluster headache. This medication may be
an option if you can't tolerate other forms of fast-acting treatments.
* Dihydroergotamine. This medication derivative is available in
intravenous, injectable and inhaler forms. Dihydroergotamine (D.H.E. 45,
Migranal) is an effective pain reliever for some people with cluster
headache. When administered intravenously, the drug requires you to go
to a hospital or doctor's office to have an intravenous (IV) line placed
in a vein. The inhaler form of the drug works more slowly.
* Octreotide (Sandostatin, Sandostatin LAR). This drug, an
injectable synthetic version of the brain hormone somatostatin, is an
effective treatment for cluster headache and is safe if you have high
blood pressure and ischemic heart disease.
* Local anesthetics. The numbing effect of local anesthetics, such
as lidocaine (Xylocaine), may be effective against cluster headache pain
when used in the form of nasal drops.
Rarely, surgery is recommended for people with chronic cluster headache
who don't respond well to aggressive treatment or who can't tolerate the
medications or their side effects. Candidates for surgery must have
headaches only on one side of the head because the surgery can be
performed only once.
Several types of surgery have been used to treat cluster headache. These
procedures attempt to damage the nerve pathways thought to be
responsible for pain. However, residual muscle weakness in your jaw or
sensory loss in certain areas of your face and head may result. Surgical
* Conventional surgery. Using a conventional invasive procedure,
your surgeon cuts part of the trigeminal nerve — the nerve that serves
the area behind and around your eye — with a scalpel or uses small burns
to destroy part of the nerve. This form of surgery can provide relief,
but has serious risks to the eye. This is no longer a procedure of first
* Glycerol injection. An injection of glycerol into the facial
nerves can provide immediate relief of symptoms with less risk than
other surgical procedures.
As scientists learn more about the causes of cluster headache, they're
able to develop more-selective treatments for the condition. One
development that shows promise is the use of a device to stimulate the
occipital nerve, which influences the trigeminal nerve. To treat people
with frequent cluster headaches, researchers are testing a stimulator — a
pacemaker-sized device that sends impulses via electrodes — that is
implanted over the occipital nerve. Several small studies, including one
by Mayo Clinic researchers, of implanted occipital nerve stimulators
found that the devices reduced chronic headache pain in some people, and
the devices were well tolerated and appeared to be very safe.
Similar research is under way using an implanted stimulator in the
hypothalamus, the area of the brain associated with the timing of
cluster periods. Deep brain stimulation of the hypothalamus may provide
relief for people with severe, chronic cluster headaches.
Whenever a cluster period starts, you'll likely start taking a long-term
medication, often accompanied by a short-term medication. After your
headaches are under control, you'll likely discontinue use of the
short-term medication but continue with the long-term drug.
Short-term medications can help prevent headache attacks during the
period of time it takes for one of the long-term drugs to become
* Corticosteroids. Inflammation-suppressing drugs called
corticosteroids, such as prednisone, are fast-acting preventive
medications. They belong to a general family of medicines called
steroids. Your doctor may prescribe corticosteroids if your cluster
headache condition has only recently started or if you have a pattern of
brief cluster periods and long remissions. Although corticosteroids are
an excellent short-term option, serious side effects make them
inappropriate for long-term use.
* Ergotamine. Ergotamine (Ergomar, others), available as a tablet
that you place under your tongue or available as a rectal suppository,
can be taken before bed to prevent nighttime attacks. Ergot medications
are effective, but can't be combined with triptans.
* Nerve block. Injecting a numbing agent (anesthetic) and
corticosteroid into the area around the occipital nerve, located at the
back of your head, can prevent pain messages from traveling along that
nerve pathway. The occipital nerve converges with the trigeminal nerve,
which connects to all the pain-sensitive structures in your skull. An
occipital nerve block can be useful for temporary relief until long-term
preventive medications take effect.
Long-term medications are taken during the entire cluster period. Some
people with chronic cluster headache may need to take two or more
long-term medications simultaneously.
* Calcium channel blockers. The calcium channel blocking agent
verapamil (Calan, Verelan, others) is often the first choice for
preventing cluster headache. Sometime after your cluster period ends,
the use of this medication is gradually tapered and discontinued under
your doctor's direction. Occasionally, longer term use is needed to
manage chronic cluster headache. Constipation is a common side effect of
this medication, as well as dizziness, nausea, fatigue, swelling of the
ankles and low blood pressure.
* Lithium carbonate. Lithium (Lithobid, Eskalith, others), which is
used to treat bipolar disorder, is also effective in preventing chronic
cluster headache. Side effects include tremor, increased urination and
diarrhea. Your doctor can adjust the dosage to minimize side effects.
While you're taking this medication, your blood will be drawn at regular
intervals to check for the development of more serious side effects,
such as kidney damage.
Other preventive medications used for cluster headache include
anti-seizure medications such as divalproex (Depakote) and topiramate
Lifestyle and home remedies
The following measures may help you avoid a cluster attack during a cluster cycle:
* Stick to a regular sleep schedule. Cluster periods may begin when
there are changes in your normal sleep schedule. During a cluster
period, follow your usual sleep routine.
* Avoid alcohol. Alcohol consumption, including beer and wine,
almost always triggers a headache during a cluster period. This can
happen quickly, even before you finish your first drink.
* Limit exposure to volatile substances. Prolonged exposure to
substances such as solvents, gasoline and oil-based paints may trigger
* Be cautious in high altitudes. During a cluster period, the reduced oxygen at high altitudes may trigger a headache.
* Avoid tobacco products. Nicotine may trigger a headache during a
cluster period. If you're prone to cluster headache, it's best to stop
smoking and avoid other tobacco products.
* Avoid nitrates. During a cluster period, nitrates may trigger a
headaches for some people. Foods that contain nitrates include smoked
and processed meats. Certain medications, such as nitroglycerin, also
may contain nitrates.
Because cluster headaches can be so painful, you may be tempted to try
alternative or complementary therapies to relieve your pain. However, a
recent survey of people with cluster headache who tried a number of
alternative therapies — including acupuncture, acupressure, therapeutic
touch, chiropractic and homeopathy — found that fewer than 10 percent
found these therapies effective.
Since they're readily available over-the-counter, some people have
turned to dietary supplements to try to ease the pain of cluster
headaches. One such supplement is melatonin, which has been found to be
present in decreased levels in people with cluster headache. But,
melatonin therapy hasn't been proved to be an effective way to ward off
these painful headaches. Be sure to check with your doctor before trying
any type of supplement because they may interact with your prescribed
Coping and support
Living with cluster headache can be very difficult. Cluster headaches
can be frightening to you and to your family and friends. The
debilitating attacks may seem unbearable. In addition to the physical
symptoms, the chronic pain that often accompanies cluster headache
attacks can make you anxious or depressed. Ultimately, it may affect
your interaction with friends and family, your productivity at work, and
the overall quality of your life.
Talking to a counselor or therapist can help you cope with the effects
of cluster headache. Or you may find encouragement and understanding in a
headache support group. Although support groups aren't for everyone,
they can be good sources of information. Group members often know about
the latest treatments and tend to share their own experiences. If you're
interested, your doctor may be able to recommend a group in your area.
Because the cause of cluster headache is unknown, you can't prevent a
first occurrence. However, a preventive strategy is crucial for managing
cluster headache because trying to treat it with only acute drugs can
seem hopeless. Prevention can help reduce the frequency and severity of
the attacks and the risk of rebound headaches. Preventive medications
can also increase the effectiveness of acute medications.
In addition, you may help reduce your risk of future attacks by avoiding
alcohol and nicotine, which often precipitate cluster headaches.