Excruciating pain occurs on one side of the head, causing the nostril and the eye on that side to water.
People are often restless and pace.
Doctors base the diagnosis on symptoms.
Oxygen (given by a face mask) or drugs are needed to treat headaches.
Most people with cluster headaches need to take drugs to prevent attacks from recurring.
(See also Overview of Headache.)
Cluster headaches are relatively rare, affecting about 4 of 1000 people in the United States. Cluster headaches are more common among men. They typically begin between the ages of 20 and 40.
A headache attack almost always starts suddenly. It may begin with nasal congestion and a watery discharge from one nostril. Excruciating pain on the same side of the head follows and spreads around the eye. The pain peaks in intensity within minutes and usually lasts 30 minutes to 1 hour but may last 15 to 180 minutes. The pain often awakens people from sleep.
People with cluster headaches, unlike those with a migraine, cannot lie down. They frequently pace and sometimes bang their head on a wall.
After the attack, the eyelid on the same side as the headache may droop, and the pupil often constricts (called Horner syndrome). The area below the eye may swell, and the eye may water. The face may be flushed. Nausea may accompany the headaches.
Headache attacks may occur several times a day, often at the same time of day or night. They usually occur regularly during a 1- to 3-month (or occasionally longer) period—called a cluster period—which is followed by a headache-free interval of several months, or even years, before attacks begin again. Alcohol may trigger headaches during a cluster period, but not during the headache-free interval. Some people do not have a headache-free interval. They have chronic cluster headaches.
Diagnosis of cluster headaches is based on the person’s description of the headache and the accompanying symptoms.
If the headaches have developed recently or if the pattern of symptoms has changed, magnetic resonance imaging (MRI) of the head or computed tomography (CT) may be done to exclude other causes.
The following may be used to stop (abort) a cluster headache as it is starting or to keep it from progressing:
Oxygen given by face mask
A triptan or dihydroergotamine given by injection (see table Some Drugs Used to Treat Migraines)
Zolmitriptan (a type of triptan) or a local anesthetic (such as lidocaine) taken by nasal spray
Cluster headaches can also be aborted by stimulating the vagus nerve (the 10th cranial nerve), which carries electrical impulses between (to and from) the brain and various parts of the head, neck, and trunk. Vagus nerve stimulation can be done noninvasively (that is, withing an incision in the skin or the insertion of an instrument into the body). To do so, people place a handheld device over the place on the neck where they can feel a pulse. This device sends a mild electrical current through the skin to activate the vagus nerve from outside the body. The current travels along the vagus nerve back to the brain and helps control the pain.
Because cluster headaches are so severe, frequent, and incapacitating, people who have them are given drugs to prevent them. These drugs include
Prednisone, a corticosteroid given by mouth
A local anesthetic plus a corticosteroid given by injection into the back of the head (a procedure called a nerve block)
Drugs used to prevent migraines (such as divalproex, topiramate, valproate, and verapamil)
Prednisone or a nerve block may be used first because they take effect more quickly. Then one of the other drugs is used for long-term prevention. A nerve block must be done in the doctor's office. The other treatments can be taken at home.