According to most estimates, approximately 90 percent of the population suffers from headaches—the most common cause of absenteeism from work and school. Migraine sufferers lose more than 157 million work and school days annually because of headache pain. About 20 percent of children and adolescents also have significant headaches. About 70 percent of those who suffer headache are women.
The most common type of headache is the tension-type headache—a mild to moderate, nonthrobbing, steady aching that spreads to both sides of the head and lasts hours to days. Other types of headaches, including migraine and cluster headaches, occur less frequently. Migraines cause mild to severe throbbing pain and can occur on one or both sides of the head. Cluster headaches are the least common type of headache and cause severe pain around one eye, which usually goes away in one to two hours and may recur over weeks or months.
Headaches may improve over time, or may disappear and then return later in life. Most people with headaches are successfully able to relieve their headache pain with over-the-counter medications. Fewer than 20 percent of Americans with bothersome headaches seek medical attention, usually after OTC medications have failed.
Although stress and tension are leading causes of headaches, there are many other factors that contribute to recurring headaches. This section offers more on:
The brain itself is not sensitive to pain. But the covering of the brain, the blood vessels, the skull, and the scalp are pain sensitive. The nerve responsible for transmitting pain impulses is the trigeminal nerve, which, along with the upper cervical spine nerve roots, is responsible for the bulk of the sensation emanating from the head and neck region.
What impetus stimulates headache pain spontaneously is not known, but the trigeminal nerve and cervical nerves are the common viaduct for pain signals, and the impulses are carried to way stations in the brain stem known as the trigeminocervical complex. Along the way, there are sites where the impulses can be modulated and even aborted.
Headache pain results when nerves of the blood vessels and head muscles are activated and send pain signals to the brain, though it's not clear why these signals are activated in the first place. People often attribute headaches to stress, and stress certainly can play a role. During stressful events, certain chemicals in the brain are released to ready the body for combat (the "flight or fight" response). The release of these chemicals can provoke vascular changes that can trigger headaches or make them worse. Stress can also contribute to the muscle tension that underlies tension headaches.
Primary headaches are those headaches that are not the result of another medical condition. This section contains information on the various types of primary headaches:
Tension headaches are the most common kind, followed by migraines.
Secondary headaches are headaches that result from another medical condition. Although headache can be a symptom of brain tumor, it far more commonly has less dramatic causes. This section also includes more on:
- Sinus headaches
- Headaches caused by temporomandibular joint (TMJ) disorders
- Post-traumatic headaches
- Underlying diseases that can cause headaches
Finally, you'll find more information in this section on:
"Tension type" headaches are the most common type of headache among adults, accounting for about 90 percent of all headaches diagnosed. There is no single cause, and tension-type headaches do not run in families. In some people, they are thought to be caused by tightened muscles in the back of the neck and scalp. This muscle tension may be an outcome of inadequate rest, poor posture, or emotional or mental stress, including depression. In others, tightened muscles are not characteristic of their headaches, and the cause is unknown.
Tension-type headaches are usually triggered by some type of environmental or internal stress. The most common sources of stress include family, social relationships, friends, work, and school. Examples of stressors include:
- Having problems at home
- Having a new child
- Having no close friends
- Returning to school or training; preparing for tests or exams
- Going on a vacation
- Starting a new job
- Losing a job
- Being overweight
- Deadlines at work
- Competing in sports or other activities
- Being a perfectionist
- Not getting enough sleep
- Being overextended, involved in too many activities
Episodic tension headaches are usually triggered by an isolated stressful situation or a buildup of stress. Daily stress, such as from a high-pressure job, can lead to chronic tension headaches. Chronic daily tension headaches affect approximately 3 percent of the population. Chronic tension headaches tend to be more common in females and in students who are high achievers.
Migraines are the second most common type of primary headache after tension headaches. No one knows exactly what causes migraines. For many years, scientists believed that migraines were linked to the dilation and constriction of blood vessels on the brain's surface. Today, migraine is thought to be a brain malfunction—a central nervous system disorder of the brain, nerves, and blood vessels.
A migraine pain center or generator sits in the midbrain area. A migraine begins when hyperactive nerve cells send out impulses to the blood vessels, causing constriction, followed by the dilation of these vessels and the release of prostaglandins, serotonin, and other inflammatory substances that make the blood vessels' pulsation painful. Certain brain cells that use serotonin as a messenger are involved in controlling mood, attention, sleep, and pain. Therefore, chronic changes in serotonin can lead to anxiety, panic disorder and depression.
Migraines cause significant discomfort and disability, but they do not usually damage the body. Migraines are not related to brain tumors or strokes.
It has been estimated that 70 percent of migraine sufferers are female. Of these female migraine suffers, 60 percent report a menstrual relationship to their migraine attack. Ten percent will suffer from migraines only at the time of their menses.
People with migraines may notice the tendency to be affected by certain migraine triggers, such as fatigue, bright lights, and weather changes. Avoiding the triggers or changing some of your behaviors can decrease the frequency of headaches.
Cyclic migraine, as its name implies, is a form of migraine that occurs in cycles. This type of headache has also been incorrectly called cluster migraine. In the absence of neurological symptoms or signs, an underlying cause is seldom found.
Causes of migraines in women
Women experience migraines more frequently than men, and to some degree, this is a result of changing estrogen levels. Menstrual migraines, for example, appear to be related to the drop in estrogen immediately before the start of the menstrual flow. Premenstrual migraines occur two to seven days prior to onset of menses, during or after the time when the female hormones estrogen and progesterone decrease to their lowest levels. Menstrual migraines are those that occur one day prior to or during menses. Some women may experience a migraine at the time of ovulation, also related to a drop in estrogen level.
The effects of estrogen fluctuation on menstrual migraine are also suggested by the disappearance of migraine attacks during pregnancy and after menopause. In one study, 64 percent of women who described a menstrual link to their headaches noted that their headaches disappeared during pregnancy. However, it also is true that pregnancy or menopause in many women marks the start of their migraines. Some women have reported the initial onset of migraines during the first trimester of pregnancy, with disappearance of their headaches after the third month of pregnancy.
Birth control pills as well as hormone replacement therapy for menopause can change the frequency or severity of headaches. If you notice your headaches getting worse after starting one of these medications, it may be worthwhile to ask your physician for an agent that contains a lower dosage of estrogen or request a change from an interrupted dosing regimen to a continuous one.
Cluster headaches are the least common—and most severe—type of primary headache. The pain of a cluster headache is intense and has a burning or piercing quality that can be either throbbing or constant. The pain is so severe that most cluster headache sufferers cannot sit still and will often pace during an attack. The pain is located behind one eye or in the eye region, without changing sides. The term "cluster" refers to the characteristic grouping of attacks: Headaches occur one to three times per day during a cluster period, which may last two weeks to three months. The headaches may disappear completely (go into "remission") for months or years, only to recur.
Cluster headaches affect fewer than 1 in 1,000 people. They are a young adult's disease; headaches typically start before age 30, are rare in children under 10, and are uncommon in teens. The headaches appear to be far more common in men than women.
The true biochemical cause of cluster headaches is unknown. However, the headaches occur when the trigeminal nerve, the chief sensory nerve of the face, is activated and causes the eye pain associated with cluster headaches. The trigeminal nerve also stimulates the parasympathetic autonomic system, which causes the eye tearing and redness, nasal congestion, and discharge associated with cluster attacks. Cluster headaches appear to be generated by the part of the brain known as the hypothalamus. Recent imaging studies have shown activation or stimulation of the hypothalamus during a cluster attack.
Researchers believe that histamines, which dilate or expand blood vessels, influence the onset because during a cluster headache, the level of histamine increases in a person's blood and urine.
Cluster headaches usually are not caused by an underlying condition such as a tumor or aneurysm.
Because cluster headaches often occur in the spring or autumn, they are often mistakenly associated with allergies or business stress. The seasonal nature of cluster headaches most likely results from stimulation or activation of the hypothalamus.
Cluster headaches are also common in people who smoke and drink alcohol frequently. During a cluster period, the sufferer is more sensitive to the action of alcohol and nicotine, and minimal amounts of alcohol can trigger the headaches. During headache-free periods the patient can consume alcohol without provoking a headache. Smoking can also increase the severity of cluster headaches during a cluster period.
Other types of primary headache include:
"Ice cream" headache. The International Headache Society criteria define this headache as pain that develops during the ingestion of cold food or drink that lasts for less than five minutes and is felt in the middle of the forehead. The headache is prevented by avoiding rapid swallowing of cold food and drink. This type of headache occurs more frequently in patients who have migraine, but it can also occur in migraine-free patients. It has been suggested that the pain is referred from the palate or teeth via the trigeminal nerve. The pain is self-limited and only rarely requires treatment.
Cough headache. Cough headache is considered by some to be a form of exertional headache and is sometimes grouped together with other headaches described as "sneezing headache" and "laughing headache." The International Headache Society defines cough headache as a headache that is felt in both sides of the head, that is of sudden onset, that lasts less than one minute, is brought on by coughing, and can be prevented by avoiding coughing.
Ice pick headache. This type of headache pain is described as momentary, sharp, or jabbing and occurring either once or several times a day at irregular intervals. It has also been nicknamed the "jabs and jolts" or "stabs and jabs" headache. The pain is most often felt around one eye or the temple area, and it recurs in the same place or may move to other places on the same side of the head or the opposite side. These headaches are more likely in patients with migraine or cluster headaches. It is uncommon in the pediatric and adolescent population. This type of headache disappears spontaneously in many cases or can be successfully treated with indomethacin.
Altitude headache. This headache is especially common in individuals who climb mountains and ski at high altitudes. It may be seen in acute mountain sickness along with other primary symptoms of pulmonary edema and cerebral edema. The headache is experienced at high altitudes (above 8,000 feet and with increasing frequency as elevation increases) and is usually associated with low oxygen levels. The headache is described as generalized and throbbing and is aggravated by exertion, coughing, and lying down. The headache usually appears from six to 96 hours after arriving at high altitudes. Relief of headache is obtained by descending to lower altitudes; oxygen inhalation and medications also work.
Chronic paroxysmal hemicrania. Also called "atypical cluster headache," this type is identified by the occurrence of multiple daily attacks—usually five per day—that last from five to 30 minutes apiece. The pain, typically severe, usually occurs on one side of the head and rarely alternate sides. Other symptoms (including eye tearing, eye redness, eyelid edema, nasal congestion, and runny nose) may be present. The pain is most frequently localized to the eye or forehead above the eye on one side of the head. The disorder responds dramatically to indomethacin, a nonsteroidal anti-inflammatory drug. When indomethacin is discontinued, the headaches reappear in several days.
Hemicrania continua. This steady, moderately intense headache is characterized by episodes of more intense pain that occur several times a day. The pain is localized to the front part of one side of the head and is not associated with nausea, although it may be accompanied by symptoms such as eye tearing, eye redness, eyelid edema, nasal congestion, and runny nose. The headache is not brought on by any particular event and the cause is not clear. Most people affected are female. Headaches typically begin during adolescence, and there is usually no family history of headache. Indomethacin is the treatment option of choice.
Occipital neuralgia. Pain is experienced at the back of the head, often starting at the upper neck or base of the skull. It may occur on one or both sides of the head and can be infrequent, can occur several times per day, or can be constant. The pain is described as jabbing or throbbing, and may radiate to the front of the head or to the eye. At times, pain can be brought on by movement, especially an overextension of the head. Other symptoms may include dizziness and, rarely, nausea and vomiting. In addition, patients report that their scalp is sensitive to the touch. Occipital neuralgia is often seen in athletes—particularly weightlifters, wrestlers, and football players—and others, such as persons involved in automobile accidents and those who incur extension and flexion injuries. Physical examination may reveal cervical area tenderness, range-of-motion limitation, and decreased sensation at the back of the head. Treatment may include use of a soft cervical collar, analgesics, muscle relaxants, local injections, and, on rare occasions, surgery.
Sinusitis, or inflammation of the sinuses, is a distinct medical condition, which may have headaches as a symptom.
Sinuses are air-filled cavities located in your forehead, cheeks, and behind the bridge of your nose. The sinuses produce a thin mucus that drains out of the channels of the nose. When a sinus becomes inflamed, usually as the result of an infection, an allergic reaction, or occasionally a tumor, the inflammation will prevent the outflow of mucus and cause a pain similar to that of a headache.
Sinusitis may have a sudden onset and be of short duration or can be a chronic condition, which is defined as at least four recurrences that last 12 weeks or longer.
Most specialists now feel that sinusitis is rarely the cause of headaches in the general population. Sinus symptoms, however, are frequent accompaniments of migraine headaches, and this explains the frequent misidentification of migraines as sinusitis-related headaches. In order for sinusitis to be considered the cause of a headache, it must be acute and must show signs of inflammation by clinical and radiological examination. Just the finding of chronic sinus changes on an X-ray exam does not qualify as proof.
The temporomandibular joint is where the lower jaw meets the skull, right in front of the ears. The cause of disorders of the temporomandibular joint is not clear, but the symptoms are thought to arise from either stress or problems with the muscles of the jaw or with the parts of the joint itself.
Possible causes include:
- Stress, which can cause a person to tighten facial and jaw muscles or clench the teeth
- Grinding the teeth, which puts pressure on the TMJ
- Presence of osteoarthritis or rheumatoid arthritis in the TMJ
The pain from TMJ disorders is usually dull and aching, occurring just below the ear on one or both sides of the face. The pain is usually localized but may expand to the temple, toward the middle of the face, or across the top and front of the skull. The pain is often aggravated by chewing. Patients frequently describe a clicking and locking of their jaw, and an examination may indicate tenderness over the jaw and joint slipping upon opening and closing the mouth. In addition, patients often cannot open their mouths widely.
Treatment for TMJ disorder usually begins with some combination of anti-inflammatory drugs, muscle relaxants, mouth splints, biofeedback, and counseling.
Patients with who have had head trauma may develop a stubborn headache later. Post-traumatic headaches are often accompanied by other symptoms including dizziness, vertigo, difficulty concentrating, memory disorders, depression, behavior disorders, and sleep alteration. This collection of symptoms together with headache is commonly called post-concussion syndrome. The severity of the symptoms does not depend on the severity of the head injury; even a trivial head injury can be enough to cause headaches.
The headaches associated with the post-concussion syndrome can be similar to a migraine headache (occurring with nausea or vomiting), a tension-type headache, or both. The headache symptoms and soft-tissue injuries may be effectively treated with mild analgesics and nonsteroidal anti-inflammatory drugs over the initial weeks. A short course of physical therapy might help. If the headache is very bad or is associated with anxiety, depression, or cognitive difficulties, more aggressive intervention may be necessary.
Regardless of treatment approach, patients are encouraged to return to normal activities as soon as possible.
When chronic headaches get worse and more frequent, and occur along with other neurological symptoms, they can be the sign of a disease in the brain that requires medical attention, such as:
- Hydrocephalus (abnormal buildup of fluid in the brain)
- Infection of the brain
- Bacterial or viral meningitis (an infection or inflammation of the membrane that covers the brain and spinal cord)
- Encephalitis (inflammation of the brain)
- Hemorrhage (bleeding within the brain)
- Brain tumor
- Blood clots and stroke
- Pseudotumor cerebri (increased intracranial pressure)
- Toxic substances (overexposure to chemicals from certain medications, such as selective serotonin reuptake inhibitors (SSRIs) Prozac or Zoloft)
- A brain malformation
Emotional stress is one of the most common triggers of migraine headaches, since migraine sufferers are generally found to be more emotionally responsive and more highly affected by stressful events. During stressful events, certain chemicals in the brain are released to cause the "flight or fight" response. The release of these chemicals can provoke vascular changes that can cause migraines. Repressed emotions surrounding stress — such as anxiety, worry, excitement, and fatigue — can increase muscle tension, contributing to tension headaches.
The following are some other common headache triggers:
- Certain foods and beverages, such as aged cheese, chocolate, beers, wines (especially red), and food additives such as nitrates (in pepperoni, hot dogs, luncheon meats) and monosodium glutamate (MSG, commonly found in Chinese food).
- Withdrawal from caffeine or a sudden drop in the body's caffeine level can cause a headache. The blood vessels seem to become sensitized to caffeine, and when caffeine is not ingested, a headache may occur. Caffeine itself is often helpful in treating acute migraine attacks.
- Changing weather conditions such as storm fronts, barometric pressure changes, strong winds, or changes in altitude
- Environmental factors such as cigarette smoke, gas fumes, perfumes
- Bright lights
- Missing meals
- Menstrual periods
- Changes in normal sleep pattern (too much or too little sleep)
Headaches can be triggered by specific environmental factors, such as exposure to secondhand tobacco smoke, strong odors from household chemicals or perfumes, exposure to certain allergens, or eating certain foods. Stress, pollution, noise, lighting, and weather changes are other environmental factors that can trigger headaches in some people.
Smoking and secondhand smoke from cigarettes, cigars, and pipes can contribute to headaches for both the smoker and the nonsmoker. Nicotine, one of the components of tobacco, stimulates vascular activity in the brain. Smoking also stimulates the ganglion nerves in the back of the throat, contributing to headache pain. Usually, by removing the stimulus (nicotine), headaches will be relieved. In one study of patients with cluster headaches, those who reduced their tobacco use by less than one-half pack of cigarettes per day found that their headaches decreased by 50 percent.
Allergy to smoke, as well as odor sensitivity, can also cause migraine headaches in some people. By avoiding situations or places where smoking is permitted, or by quitting smoking, most people can reduce the onset of migraine headache.
When some individuals exercise or exert themselves, they can develop "exertional" headaches. These headaches, including the jogger's headache and those that accompany orgasm, can be abrupt in onset and sharp and severe. Exercise can also exacerbate migraines.
While exertional headaches may occur in isolation, they are most common in patients who have an inherited susceptibility to migraine because one or both parents have migraines. Most exertional headaches are benign and respond to usual headache therapy. Some are particularly responsive to indomethacin, an anti-inflammatory agent. However, exertional headaches should be evaluated to exclude other medical causes.
Headaches, especially migraines, have a tendency to run in families. Four out of 5 migraine sufferers have a family history of migraines. Children who have migraines usually have at least one parent who also suffers from the condition. If one parent has a history of migraines, the child has a 50 percent chance of developing migraines, and if both parents have a history of migraines, the risk jumps to 75 percent. People with migraines may inherit abnormalities in certain areas of the brain, as well as the tendency to be affected by certain migraine triggers, such as fatigue, bright lights, or weather change.
Last reviewed on 07/06/2006
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