Cluster headaches, which occur in cyclical patterns or cluster periods, are one of the most painful types of headache. A cluster headache commonly awakens you in the middle of the night with intense pain in or around one eye on one side of your head.
Bouts of frequent attacks, known as cluster periods, can last from weeks to months, usually followed by remission periods when the headaches stop. During remission, no headaches occur for months and sometimes even years.
Fortunately, cluster headache is rare and not life-threatening. Treatments can make cluster headache attacks shorter and less severe. In addition, medications can reduce the number of cluster headaches you have.
Common signs and symptoms
- Cluster headache signs and symptoms affecting the face - A cluster headache strikes quickly, usually without warning, although you might first have migraine-like nausea and aura. Common signs and symptoms during a headache include:
- Excruciating pain that is generally situated in, behind or around one eye, but may radiate to other areas of your face, head and neck
- One-sided pain
- Excessive tearing
- Redness of your eye on the affected side
- Stuffy or runny nose on the affected side
- Forehead or facial sweating on the affected side
- Pale skin (pallor) or flushing on your face
- Swelling around your eye on the affected side
- Drooping eyelid on the affected side
- People with cluster headache, unlike those with migraine, are likely to pace or sit and rock back and forth. Some migraine-like symptoms - including sensitivity to light and sound - can occur with a cluster headache, though usually on one side.
A cluster period generally lasts for several weeks to months. The starting date and the duration of each cluster period might be consistent from period to period. For example, cluster periods can occur seasonally, such as every spring or every fall.
Most people have episodic cluster headaches. In episodic cluster headaches, the headaches occur for one week to a year, followed by a pain-free remission period that can last as long as 12 months before another cluster headache develops.
Chronic cluster periods might continue for more than a year, or pain-free periods might last less than one month.
- Headaches usually occur every day, sometimes several times a day
- A single attack can last from 15 minutes to three hours
- The attacks often occur at the same time each day
- Most attacks occur at night, usually one to two hours after you go to bed
- The pain usually ends as suddenly as it began, with rapidly decreasing intensity. After attacks, most people are pain-free but exhausted.
See your doctor if you've just started to have cluster headaches 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 can 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. Seek emergency care if you have any of these signs and symptoms:
- An abrupt, severe headache, often like a thunderclap
- A headache with a fever, nausea or vomiting, a stiff neck, mental confusion, seizures, numbness, or speaking difficulties, which can indicate a number of problems, including a stroke, meningitis, encephalitis or a brain tumor
- A headache after a head injury, even if it's a minor fall or bump, especially if it worsens
- A sudden, severe headache unlike any you've had
- A headache that worsens over days and changes in pattern
The exact cause of cluster headaches is unknown, but cluster headache patterns suggest that abnormalities in the body's biological clock (hypothalamus) play a role. Unlike migraine and tension headache, cluster headache generally isn't associated with triggers, such as foods, hormonal changes or stress.
Once a cluster period begins, however, drinking alcohol may quickly trigger a splitting headache. For this reason, many people with cluster headache avoid alcohol during 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:
- Sex. Men are more likely to have cluster headaches.
- Age. Most people who develop cluster headaches are between ages 20 and 50, although the condition can develop at any age.
- Smoking. Many people who get cluster headache attacks are smokers. However, quitting smoking usually has no effect on the headaches
- Alcohol use. If you have cluster headaches, drinking alcohol during a cluster period may increase your risk of an attack.
- A family history. Having a parent or sibling who has had cluster headache might increase your risk.
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.
How often your headaches occur and how long they last also are important factors.
Your doctor will likely try to pinpoint the type and cause of your headache using certain approaches.
A neurological examination may help your doctor detect physical signs of a neurological disorder. The exam is usually normal in patients with cluster headaches. Your doctor will use a series of procedures to assess your brain function, including testing your senses, reflexes and nerves.
If you have unusual or complicated headaches or an abnormal neurological examination, your doctor might recommend other tests to rule out other serious causes of head pain, such as a tumor or an aneurysm. Common brain imaging tests include:
MRI. This uses a powerful magnetic field and radio waves to produce detailed images of your brain and blood vessels.
CT scan. This uses a series of X-rays to create detailed cross-sectional images of your brain.
There's no cure for cluster headaches. The goal of treatment is to decrease the severity of pain, shorten the headache period and prevent the attacks.
Because the pain of a cluster headache comes on suddenly and might subside within a short time, cluster headache can be difficult to evaluate and treat, as it requires fast-acting medications.
Some types of acute medication can provide some pain relief quickly. The therapies listed below have proved to be most effective for acute and preventive treatment of cluster headache.
Fast-acting treatments available from your doctor include:
1. Oxygen. Briefly inhaling pure oxygen through a mask provides dramatic relief for most who use it. The effects of this safe, inexpensive procedure can be felt within 15 minutes.
Oxygen is generally safe and without side effects. 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.
2. Triptans. The injectable form of sumatriptan (Imitrex), which is commonly used to treat migraine, is also an effective treatment for acute cluster headache.
The first injection may be given while under medical observation. Some people may benefit from using sumatriptan in nasal spray form, but for most people this isn't as effective as an injection and it may take longer to work. Sumatriptan isn't recommended if you have uncontrolled high blood pressure or heart disease.
3. 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.
Oral medications are relatively slow to act and are often not useful for acute treatment of cluster headaches.
5. Local anesthetics.
Preventive therapy starts at the onset of the cluster episode with the goal of suppressing attacks. Determining which medicine to use often depends on the length and regularity of your episodes. Under the guidance of your doctor, you can taper off the drugs once the expected length of the cluster episode ends.
- Lithium carbonate.
- Nerve block. Injecting a numbing agent (anesthetic) and corticosteroid into the area around the occipital nerve, situated at the back of your head, might improve chronic cluster headaches. Potential future treatments
- Occipital nerve stimulation. In this procedure, your surgeon implants electrodes in the back of your head and connects them to a small pacemaker-like device (generator). The electrodes send impulses to stimulate the area of the occipital nerve, which may block or relieve your pain signals. Several small studies of occipital nerve stimulation found that the procedure reduced pain and frequency of headaches in some people with chronic cluster headaches.
- Deep brain stimulation. Deep brain stimulation is a promising but as yet unproven treatment for cluster headaches that don't respond to other treatments. In this procedure, doctors implant an electrode in the hypothalamus, the area of your brain associated with the timing of cluster periods. Your surgeon connects the electrode to a generator that changes your brain's electrical impulses and may help relieve your pain. Because this involves placing an electrode deep in the brain, there are significant risks, such as an infection or hemorrhage. Deep brain stimulation of the hypothalamus may provide relief for people with severe, chronic cluster headaches that haven't been successfully treated with medications.
Calcium channel blockers.
Side effects may include constipation, nausea, fatigue, swelling of the ankles and low blood pressure.
Researchers are studying several potential treatments for cluster headache.
Lifestyle and home remedies
The following measures may help you avoid a cluster headache attack during a cluster cycle:
- Stick to a regular sleep schedule. Cluster periods can 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, can quickly trigger a headache during a cluster period.