What is cluster headache? Cluster headache is a rare type of headache disorder. It is an extremely painful headache that affects one side of the head. Most commonly, the pain occurs around or behind an eye. Cluster headache also causes autonomic symptoms on the same side of the face. Autonomic refers to the involuntary nervous system, which controls such body functions as sweating and flushing. Some people have an aura before a cluster headache, similar to migraine headache. Due to the severity of the pain, cluster headaches are sometimes called suicide headaches. The name, cluster, comes from the fact that these headaches usually occur in episodes. Typically, the headache strikes at the same time of day for many days in a row, for weeks or months at a time. This is followed by long headache-free periods. These remissions can last for months or years. Men tend to suffer with cluster headaches more often than women. The headache episodes usually start between the ages of 20 and 50 years. Fortunately, treatment can help stop the symptoms and prevent future attacks. See your doctor if you have symptoms that suggest cluster headache. Getting an accurate diagnosis is important. Most of the time, even severe headache pain is not related to any other problem. However, in some cases, severe headache pain can be a sign of an underlying condition. Seek immediate medical care (call 911) if you have any of the following symptoms: Headache after any type of head injury, even a minor impact Headache pain that worsens over several days Headache with fever, stiff neck, confusion, nausea, vomiting, seizures, or difficulty walking, talking or understanding speech Sudden, severe headache pain What are the symptoms of cluster headache? Pain is the main symptom of cluster headache. It is located on one side of the head, usually behind, above or around the eye. Cluster headache pain is severe and can last for 15 minutes to three hours. People describe the pain as unbearable piercing, boring, or burning in the eye. The pain usually starts quickly and often strikes during the night. In some cases, an aura occurs before the pain starts. It is similar to a migraine aura, which can include vision changes, dizziness or nausea. Cluster headache attacks typically happen at the same time of day. They can occur up to eight times in a day, with an average occurrence of twice per day. There are two main types of cluster headaches: Chronic cluster headaches happen daily for more than a year with no remission or with remissions shorter than a month Episodic cluster headaches last anywhere from a week to a year with remissions between episodes lasting a month or longer Most people have episodic cluster headaches, with 4 to 6 week episodes. Other symptoms of cluster headache Other cluster headache symptoms occur on the same side of the face as the pain and include: Eye redness or tearing Eyelid drooping Facial sweating or flushing Nasal congestion or runny nose Swelling around the eye It is also possible to experience general restlessness, anxiety or agitation. Symptoms that might indicate a life-threatening condition In some cases, severe headache pain can be a sign of a potentially life-threatening condition. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including: Headache after bumping or injuring the head Headache pain that gets progressively worse over several days Headache accompanied by fever, stiff neck, confusion, nausea, vomiting, or seizures Headache accompanied by difficulty walking, talking or understanding speech, which are symptoms of stroke Sudden, severe headache pain See your doctor if you have symptoms of cluster headache. Seeking an early diagnosis can help you find effective relief and prevent future attacks. Experts do not know exactly what causes cluster headache. Theories focus on the pattern of cluster headaches, which suggest a problem with the body’s circadian—or daily—rhythm. This may mean cluster headache is somehow related to the hypothalamus—a small area of the brain that controls body systems, hormones and rhythms. Cluster headache is considered a multifactorial disease, one that involves both genetic and environmental causes. Genetic studies are in progress to identify specific genes linked to the disorder. What are the risk factors for cluster headache? Several factors tend to increase the risk of developing cluster headache. Risk factors for cluster headache include: Age 20 to 50 years Family history of cluster headache Male biological sex Smoking Alcohol use, especially red wine, can trigger headaches during an episode period. However, once the episode subsides and remission begins, alcohol usually is not a problem. Reducing your risk of cluster headache Reducing your risk of a disease often means altering risk factors that are under your control. Unfortunately, most risk factors—age, being born male, and family history—are not modifiable. If you have cluster headache risk factors, you may be able to lower your risk by not smoking and avoiding alcohol during an episode. Talk with your doctor about your lifestyle and ask if other changes could help lower your risk. How is cluster headache treated? Like migraine treatment, cluster headache treatment has two goals—treat the acute attack and prevent future headaches. Acute cluster headache treatment aims to reduce pain and other symptoms. Treatment needs to start immediately because cluster headache pain escalates quickly. Acute treatment may include the following: Oxygen: Inhaling 100% oxygen by mask can be highly effective. However, convenience can be an issue with this treatment. Immediate access to this treatment means carrying a portable oxygen source. Triptans: These medications are common migraine treatments. They also work well for cluster headache. The injectable forms are the fastest acting, but nasal sprays may also be an option for some people. Examples include sumatriptan (Imitrex) and zolmitriptan (Zomig). Other injectable medicines: Octreotide (Sandostatin) and dihydroergotamine (D.H.E. 45) may be effective for some people with cluster headaches. Dihydroergotamine is also available as a nasal spray under the brand name, Migranal. Preventive treatment aims to reduce the number of attacks once an episode begins. Preventive treatments may include the following: Verapamil (Calan, Veralan) is a common first-line medicine for preventive treatment. It is an oral medicine belonging to the calcium channel blocker class. Corticosteroids, such as prednisone, can be helpful for short-term use. Doctors typically avoid long-term use because serious side effects can become a problem. Lithium may be an option for chronic cluster headache. Melatonin is a supplement that may help cluster headache sufferers by helping to regulate sleep-wake cycles. Nerve block injections containing a local anesthetic and corticosteroid can provide relief while other preventive treatments are starting. This injection goes into the back of the head to numb the occipital nerve. Topiramate and other anti-seizure medicines may help some people with cluster headache. Galcanezumab and possibly other antibody drugs that block or inhibit CGRP, a substance that causes migraine pain. Galcanezumab (Emgality) has been approved for reducing migraine frequency, and is currently under study for cluster headache. Once an episode subsides, some of these medicines require a dose tapering before stopping them. This allows the doctor to slowly and safely lower the dose. If you take preventive treatment, check with your doctor to find out how to stop your medicine. What are the potential complications of cluster headache? The main complication of cluster headache is the disorder’s effect on quality of life. The severity of the pain and difficulty of the disorder often leads to chronic anxiety and depression. It can also affect your social interactions, personal relationships, and work activities. All of this can contribute to a poor quality of life. Emotional and social support is an important part of dealing with cluster headache. You can find help through individual counseling sessions. Headache support groups are also an option and let you connect with others who understand your experience. If you need help locating support, talk with your doctor and ask for recommendations.