Headache is a pain or discomfort felt in the head. It is not a disease but a symptom of some other problem in the body, thus there are many possible causes. When someone gets a headache, it usually is temporary, and only very rarely is it a sign of serious illness.

What Are Headaches?


Prehistoric people are known to have surgically cut holes in the skull of living persons, presumably to relieve some ailment. This procedure is called trephining (tre-FAN-ing). The purpose of this operation is not known with certainty. Perhaps it was carried out to relieve the pressure of a blood clot * under the skull caused by a blow to the head. However, it is believed that in some instances it may have been done in an attempt to cure headaches by releasing evil spirits. Stone Age patients who underwent this surgery apparently often survived, because many of the skulls found by scientists showed new growth of bone around the holes.

The primary cluster headache symptom is excruciating one-sided head pain located behind an eye or near the temple. Secondary symptoms include eye tearing, nasal congestion, and a runny nose.

The primary cluster headache symptom is excruciating one-sided head pain located behind an eye or near the temple. Secondary symptoms include eye tearing, nasal congestion, and a runny nose.
Illustration by Electronic Illustrators Group. © 2016 Cengage Learning®.

Up to 50 million people in the United States annually seek medical help for migraine and other severe headaches. Every 10 seconds, someone in the United States goes to the emergency room with a migraine or other type of headache. The lost work hours due to migraine and other headaches cost an estimated $13 billion every year in the United States. It has been estimated that more than $1 billion is spent each year for over-the-counter remedies to relieve headaches.

A large percentage of women's headaches are related to their menstrual cycle * . Chronic * headaches may accompany emotional disturbances such as depression. Many times, headaches are just one of a number of symptoms, such as fever or dizziness, which are brought on by various diseases or injuries. Migraine headaches frequently are accompanied by nausea and other symptoms that are characteristic of the disorder.

What Are the Causes and Types of Headaches?

The pain of headache may be mild, extremely severe, or anywhere in between. It may involve the entire head, one side only, the forehead, or the base of the skull, or it may seem to move around. The pain may be sharp, a dull ache, or throbbing. A headache may last a few minutes or hours. It may recur from time to time, or it may become chronic, coming back many times over an extended period.

Many people believe that the brain itself is involved in headaches, but neither the brain nor the skull has nerves that register pain. The sources of head pain are the nerve endings in the blood vessels and muscles in and around the head. Pain may be felt when these tissues become stretched, inflamed, or damaged. Headaches can arise in blood vessels within the brain, as well as in the meninges (meh-NIN-jeez), which are the sensitive membranes that cover the brain.

* can produce pain in the front of the head and around the eye. Mastoiditis, an inflammation of the bone behind the ear, can cause severe pain on the affected side of the head. Sinusitis * can cause sharp headaches in the front of the head (often called sinus headaches). A jaw or bite that does not close properly can also cause headache.

Many types of infection with fever, such as influenza (flu), cause headache. Other causes include drinking too much alcohol, heavy smoking, withdrawal * from caffeine, or inhaling a noxious gas, such as carbon monoxide. Contrary to popular belief, high blood pressure rarely is a direct cause of headache.

Headache is one of the symptoms of concussion and sometimes becomes chronic following this injury.

Rarely, headaches may be caused by brain abscesses, brain tumors * , bleeding into the brain, and meningitis (an inflammation of the membranes covering the brain).

Physicians often classify headaches as those caused by disease or injury; tension headaches; and vascular * headaches. Vascular headaches include migraine and a type called cluster headaches. Tension and migraine headaches are very common.

Tension headache is the most common type of headache and is caused by severe muscle contractions triggered by stress or exertion.

Tension headache is the most common type of headache and is caused by severe muscle contractions triggered by stress or exertion. Tension headaches usually occur in the front of the head, although they may also appear at the top or the back of the skull, as shown.
Illustration by Electronic Illustrators Group. © 2016 Cengage Learning®.

What Are Tension Headaches?

Headaches that are associated with emotional stress or muscular tension are called tension headaches. The muscular tension may be in the neck, face, or scalp. It may be the result of poor posture or of constantly bending over one's work. These headaches are extremely common, and almost everyone has them at one time or another. A person may have one after working on the computer too long or bending over while doing homework.

Pressures from school, friends, or family may play a role. Adults may develop tension headaches because of stress at work. Tension headaches may be mild to moderate and occur in various parts of the head. The feeling has been described as a steady ache or as a tight sensation.

The pain of tension headaches can be chronic or recurrent, sometimes coming on every day. Muscles near the site of the pain, such as at the back of the neck or on the sides of the head, are often tense and tender. Sometimes chronic tension headache is a symptom of depression.

Antimigraine drugs

Antimigraine drugs
Table by Lumina Datamatics Ltd. © 2016 Cengage Learning®.

What Are Migraine Headaches?

Migraine is a moderate to severe headache that can interfere with a person's activities. The pain is typically, although not always, in one side of the head, at least at the beginning, and may last from hours to days. Migraine headaches occur every so often, usually beginning in adolescence or early adulthood. They tend to become less frequent with age and tend to be rare or absent after the age of 40 to 50 years.

Migraine is one of the most common types of headaches, affecting about 20 million people in the United States alone. Women are four times more likely to experience migraine than men. People in all walks of life have been afflicted, including Sigmund Freud (psychologist), Thomas Jefferson (U.S. president), Charles Darwin (geologist and evolutionary biologist), and Lewis Carroll, the author of Alice in Wonderland. Modernday sufferers include Diana, Princess of Wales, of Great Britain and basketball player Kareem Abdul-Jabbar.

The cause of migraine headaches was not known as of 2016. They have been classified as vascular headaches because blood vessels in the head dilate (expand) during an attack. It was believed that certain chemical substances in the nerve cells surrounding the vessels are involved in the attack. The precise mechanism was not fully understood.

Migraine headaches tend to run in families. However, one does not catch this type of headache from someone else.

Most migraine attacks begin without warning. Typically, the pain is throbbing, often growing in intensity. It usually is accompanied by nausea and sometimes vomiting. The slightest noise or movement can make it worse. Ordinary light coming through a window may be unbearable.

The Aura

In about 15 percent of people who get migraines, the headaches are preceded by a distinctive type of warning called an aura (OR-uh). An aura can be a blank spot in the vision bordered by zigzag and flashing lights or numbness or weakness in parts of the body. After several minutes, the aura goes away and the pain of the headache begins. Migraine preceded by an aura has been called a classic migraine or migraine with aura.

Brain Freeze

Ice cream headaches, often called “brain freeze,” are medically referred to as cold stimulus headaches. These are brief, stabbing headaches that can occur when eating or drinking something that is very cold. Ice cream is a common trigger, but other frozen foods can have the same effect. This type of headache passes quickly without need for medications.

What Are Cluster Headaches?

Intensely painful headaches that occur one or more times daily are called cluster headaches. These headaches may recur for weeks or months, then not return for years. The pain is centered on one side of the head around the eye. Besides pain, the symptoms include a watery eye on the affected side and a runny nose.

Cluster headaches occur in men more often than in women and usually first appear when people are about 40 years of age. The cause was unknown as of 2016.

When Should People with a Headache See a Doctor?

Most headaches, although unpleasant, are not signs of serious health problems. A person should see a doctor if the headaches are unusually persistent or severe, if there are any changes in vision or speech, or if there is weakness or numbness in any body part. A doctor or other medical professional should be consulted whenever a headache is accompanied by neck stiffness, a high fever, loss of consciousness, or confusion. Treatment should not be delayed for any headache that is sudden and severe or that occurs after a head or neck injury. Children who experience recurrent headaches should be seen by a doctor. People with established chronic headaches who experience any sudden change in headache pattern or intensity should consult with a doctor. These changes are a cause for concern and should be investigated.

How Are Headaches Treated?

Over-the-counter pain-relieving drugs, such as acetaminophen or ibuprofen, may ease mild headaches. Relief also may come from such simple measures as getting some fresh air, taking a hot bath, getting a muscle massage, or lying down for a while. Tension headaches can be dealt with by addressing the cause of the emotional or physical stress.

For severe headaches, such as migraine, the best approach is prevention, that is, avoiding the factors that the individual knows are most likely to trigger an attack. Once an attack begins, pain-relieving drugs may help to ease symptoms. The doctor can also prescribe medicines that will narrow the blood vessels in the brain that have dilated during an attack. If migraine attacks occur frequently, the doctor can prescribe medications to prevent the migraine. Biofeedback, a relaxation technique, has proven helpful in relieving and avoiding some headaches.

Cluster headache attacks may be over before pain-relieving drugs can take effect. However, some prescription medicines may be useful in prevention.

Many common headaches can, of course, be prevented by maintaining a healthy lifestyle, including regular eating and sleeping habits, not using any products containing tobacco, and avoiding excess alcohol and caffeine intake.

See also Ear Infections (Otitis) • Glaucoma • Sinusitis • Stress and Stress-Related Illness • Temporomandibular Joint (TMJ) Syndrome


Books and Articles

Chronic Conditions Team. “When It Feels Like a Headache—But Isn't.” Health Essentials, September 3, 2015. http://health.clevelandclinic.org/2015/09/when-it-feels-like-a-migraine-but-isnt (accessed September 21, 2015).

Hochwald, Lambeth. “What Type of Headache Do I Have?” Mother Nature Network, September 16, 2015. http://www.mnn.com/health/fitness-well-being/stories/what-type-headache-do-I-have (accessed September 21, 2015).

“Migraine Severity Linked to Cholesterol Levels.” Renal and Urology News, September 17, 2015. http://www.renalandurologynews.com/cardiovascular-disease-cvd/migraine-severity-linked-to-cholesterol-levels/article/438058 (accessed September 21, 2015).

Morrone, Lisa. Overcoming Headaches and Migraines. Eugene, OR: Harvest House, 2008.

Ruoff, Gary. Knock Out Headaches. Ann Arbor, MI: Spry, 2013.


ACHE. “Tension-Type Headaches—The Basics.” American Headache Society. http://www.achenet.org/resources/tensiontype_headaches__the_basics (accessed June 7, 2016).

American Chiropractic Association (ACA). “Headaches & Chiropractic.” https://www.acatoday.org/content_css.cfm?CID=2186 (accessed July 16, 2015).


American Academy of Family Physicians. PO Box 11210, Shawnee Mission, KS 66207-1210. Toll-free: 800-274-2237. Website: http://www.aafp.org (accessed July 16, 2015).

American Academy of Neurology. 201 Chicago Ave., Minneapolis, MN 55415. Toll-free: 800-879-1960. Website: http://www.aan.com (accessed July 16, 2015).

American Headache Society. 19 Mantua Rd., Mt. Royal, NJ 08061. Telephone: 856-423-0043. Website: https://americanheadachesociety.org/ (accessed June 7, 2016).

National Headache Foundation. 820 N. Orleans, Suite 411, Chicago, IL 60610. Toll-free: 888-643-5552. Website: http://www.headaches.org (accessed July 16, 2015).

* blood clot is a thickening of the blood into a jellylike substance that helps stop bleeding. Clotting of the blood within a blood vessel can lead to blockage of blood flow.

* menstrual cycle (MENstroo- al SY-kul) culminates in menstruation (men-stroo-AYshun), the discharging through the vagina of blood, secretions, and tissue debris from the uterus that recurs at approximately monthly intervals in females of reproductive age.

* chronic (KRAH-nik) means lasting a long time or recurring frequently.

* glaucoma is a group of disorders that cause pressure to build in the eye, which may result in vision loss.

* glaucoma is a group of disorders that cause pressure to build in the eye, which may result in vision loss.

* withdrawal is a group of symptoms that occurs when a drug that causes physical or psychological dependence is regularly used for a long time and then suddenly discontinued or significantly decreased in dosage.

* tumors (TOO-morz) are abnormal growths of body tissue that have no known cause or physiologic purpose. Tumors may or may not be cancerous.

* vascular refers to veins and arteries (the blood vessels).

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)