Pain occurring in the head is known as a headache. Headaches are one of the most common medical complaints.

People may experience pain in the nerves extending over the scalp and specific nerves located in the face, mouth and throat. The muscles of the head and the blood vessels located on the surface and base of the brain may also become painful.

Although the cause of many headaches is unclear, researchers have identified a number of causes and potential causes, including contractions of muscles and dilation of blood vessels. In addition to pain, headaches may be accompanied by a number of other signs and symptoms including nausea, vomiting, runny nose, fatigue and sensitivity to light or sound.

The International Headache Society lists more than 150 types of headache. The majority can be classified as either primary (not caused by an underlying condition) or secondary (caused by other factors such as injury or infection).  Tension headaches, migraines and cluster headaches are among the most common types of primary headache.

The many other causes of head pain include cranial neuralgias, occipital neuralgia, chronic fatigue syndrome, fibromyalgia, myofascial pain syndrome, encephalitis, meningitis, Lyme disease, temporal arteritis, TMJ disorder and whiplash. 

Headaches are often reactions to certain factors. Common triggers include dietary factors, hormonal changes, sensory stimulus, emotions and uncorrected farsighted or nearsighted vision.

In most cases, headaches do not require medical attention. Serious or recurring headaches should be discussed with a physician. To determine the type of headache being experienced, a physician will take a patient’s medical history and perform a physical examination. Diagnostic tests such as MRI or CAT scan may be ordered to help identify the cause of the headache or rule out a serious underlying cause.

After the source of the head pain is determined, the physician may recommend lifestyle changes, prescribe headache medications or recommend other treatments, such as biofeedback, cold therapy or physical therapy.

Most headaches are not caused by life-threatening disorders. In rare cases, however, they can indicate a serious underlying condition such as a stroke, brain tumor or aneurysm. Patients should seek emergency medical treatment when headaches are accompanied by unusual symptoms not experienced during previous headaches, such as speech problems, vision abnormalities or numbness, or if they have “the worst headache of their life.”

Headache is a term used to describe pain or discomfort in the head. The condition may be triggered by a number of factors.

Many areas of the head can become painful. These include the nerves extending over the scalp and specific nerves located in the face, mouth and throat. Other areas of the head, such as jaw muscles and the blood vessels located on the surface and base of the brain, are also susceptible to pain. The bones of the skull and brain tissue cannot become painful because they do not contain pain-sensitive nerve fibers.  

Pain occurs when the ends of pain-sensitive nerves are stimulated. Known as nociceptors, the nerve endings may be stimulated by a number of factors including stress, dilation of blood vessels and muscle tension. When a nociceptor is stimulated, it transmits messages to the nerve cells in the brain. This alerts the brain that part of the body is in pain.

Different areas of the body send different pain messages to the brain. The message is based on the location of the affected nociceptor. For example, a person who experiences pain in the finger is responding to nociceptors located in the hand.    

Headache is one of the most common medical complaints. According to the American Council for Headache Education, nearly 90 percent of men and 95 percent of women have had at least one headache during the past year. Although the condition can cause debilitating pain, headaches are rarely due to life-threatening disorders.

There are many types of headache. The International Headache Society has composed a comprehensive list of more than 150 types of headache. According to the society’s classification of headache disorders, headaches may be categorized as primary, secondary or cranial neuralgias.

Primary headaches are often a tension headache, migraine or cluster headache. Secondary headaches can be caused by numerous underlying conditions or injuries, such as head or neck trauma or disorders, blood vessel disorders within the head and neck, infection, tumor, facial pain, certain eye conditions, and many substances including medications.

Cranial neuralgias (nerve pain in the head) include central and primary facial pain and other headaches.

According to the American Council for Headache Education, more than 90 percent of headaches are primary headaches. Headaches classified as primary are not due to an underlying condition and are typically not life-threatening.   

The most common types of primary headache include:

• Tension headache. Also known as a tension-type headache, this is the most common form of headache. It typically produces a dull and pressure-like pain in the head, neck and scalp. Tension headaches are most common in patients between the ages of 30 and 39. The condition is also more common in women. This type of headache typically develops early in the day, often after a person wakes up.
  
  
• Migraine. This is the second most common form of headache. It typically appears as a throbbing ache near one side of the forehead. Migraines may be accompanied by a number of other symptoms, including nausea, vomiting and temporary visual changes (aura). The condition occurs most often in women and patients between the ages of 15 and 55. Migraines are also more likely to occur in people with migraine sufferers in their immediate family (e.g., parent, sibling).
  
  
• Cluster headache. Typically appears as a sharp, penetrating or burning pain, usually involving only one side of the head. The pain is most often felt in or around the eye or in the temple. Many times the head pain is accompanied by drooping of the eyelid and nasal congestion on the same side as the pain. This type of headache usually appears as a series of headaches (cluster), separated by pain-free periods of remission lasting for months or years. It is more common in men than women. 

Other types of primary headache include:

• Primary cough headache. This type of headache can be triggered by coughing, as well as sneezing, laughing or bending over. It typically appears as a sharp or stabbing pain located on both sides of the head and at the back of the skull. It usually develops suddenly and lasts anywhere from a few seconds to several minutes. Primary cough headaches occur more often in men.
  
  
• Primary exertional headache. This type of headache is triggered by prolonged physical exercise (e.g., weightlifting, running, dancing). They typically produce a throbbing pain on both sides of the head. The pain, which slowly intensifies, can last anywhere from five minutes to 48 hours.
  
  
• Primary headache associated with sexual activity. This type of headache can occur during intercourse (preorgasmic headache) or during orgasm (orgasmic headache). Preorgasmic headache typically appears as a dull ache in the head and neck that slowly intensifies with sexual excitement. Orgasmic headaches usually present as a severe pain during orgasm. The head pain associated with sexual intercourse may last anywhere from a minute to three hours. Sexual pain is also known as dyspareunia.
  
  
• Primary thunderclap headache. This form of headache produces severe pain that typically reaches peak intensity in less than a minute. The pain can last anywhere from an hour to several days.

Unlike primary headaches, secondary headaches are symptoms of other diseases or conditions. Types of secondary headache include:

• Sinus headache. Headache may accompany sinusitis, a common condition involving inflammation of the sinuses. Indicators include orofacial pain over the cheeks and forehead and sometimes eye pain. It can be confused with a migraine. People prone to colds and allergies face increased risk of sinus headache.
  
  
• Delayed alcohol-induced headache. Also known as hangover headaches, delayed alcohol-induced headaches typically appear as a pulsating pain in the front and on both sides of the head. This type of pain, which may occur after a period of excessive drinking, can intensify with movement.
  
  
• Monosodium glutamate-induced headache. Monosodium glutamate (MSG) is a food additive often found in Chinese foods, meat tenderizers, processed meats, canned soups and other processed foods. Foods containing the ingredient can trigger a dull and constant pain at the front or on both sides of the head. It typically occurs within 30 minutes of consumption and resolves within 72 hours.
  
  
• Medication-overuse headache. Also known as an analgesic rebound headache, this type of headache results from overuse of pain medication. Taking prescription or nonprescription medication daily or almost daily can cause a headache to rebound as the medication begins to wear off.
  
  
• External compression headache. Continuous pressure on the forehead or scalp can trigger a headache. Placing certain objects on the head, such as a tight hat, goggles or a headband, can cause constant head pain. This pain is typically worse in the area where the object is pressing on the head. 
  
  
• Headache attributed to ingestion or inhalation of a cold stimulus. Commonly referred to as an ice cream headache, this type of headache results from cold material moving along the palate and across the throat. It may be triggered by quickly consuming ice cream, a cold drink or inhaling cold air. The pain, which typically appears as a sharp, stabbing pain in the forehead, usually peaks about 30 seconds after it develops and resolves within two minutes.
  
  
• Headache attributed to low cerebrospinal fluid pressure. Also known as a post-lumbar puncture headache, this type of headache may occur after a spinal tap (lumbar puncture). A spinal tap is a procedure in which a needle is used to remove a sample of cerebrospinal fluid from between vertebrae in the lower spine. It typically appears within one week after the procedure and usually disappears within two to three weeks or after treatment for a spinal fluid leak. This type of headache is usually worsened by standing, straining (e.g., cough) or sitting up and relieved by lying down.
  
  
• Carbon monoxide-induced headache. Carbon monoxide is a colorless, odorless gas that reduces the body’s ability to carry oxygen to the brain. Carbon monoxide poisoning can trigger a dull and constant pain in the head. The pain typically disappears within 72 hours after a person stops breathing the gas. Sources of carbon monoxide include exhaust from combustion engine (e.g., automobile engines), portable propane heaters, barbecue charcoal, and portable or non-vented natural gas appliances.

The many other causes of head pain include cranial neuralgias, occipital neuralgia, fatigue, chronic fatigue syndrome, fibromyalgia, myofascial pain syndrome, encephalitis, meningitis, Lyme disease, temporal arteritis, TMJ disorder, whiplash and lupus.

Headache may also be due to referred pain from sources of dental pain, ear pain, eye pain, neck pain or shoulder pain.

The exact cause of most headaches is unknown. Researchers have identified a number of causes and potential causes.

The process resulting in head pain differs between headache types. Headaches may be diagnosed as:

• Vascular. This group of headaches, including migraines and cluster headaches, results from the dilation (swelling) of the blood vessels in the brain.  
  
  
• Muscle contraction. Headaches contained in this group, which includes tension headache, appear to develop as the result of tightening or tensing of muscles in the face and neck, or possibly from the restriction of blood flow to the brain.
  
  
• Traction. This group of headaches results from the pulling or stretching of pain-sensitive parts of the head. For example, tensing the eye muscles to compensate for eyestrain can trigger this form of headache. They are typically symptoms of other conditions.

• Inflammatory. Headaches contained in this group, such as sinus headache, result from inflammation. The inflammation may be related to a number of conditions including diseases of the sinuses, spine, neck, ears and teeth.
  
  
• Idiopathic. Without any known cause. 

A number of factors may trigger or intensify a primary headache, including:

• Diet (e.g., alcohol, monosodium glutamate, caffeine, chocolate, nuts, nitrates and nitrites, tyramine)
  
  
• Hormonal changes (e.g., menstruation, pregnancy, menopause, birth control pills, hormone replacement therapy)
  
  
• Sensory stimulus (e.g., bright lights, loud noises, certain odors)
  
  
• Emotions (e.g., stress, depression, anxiety)
  
  
• Fatigue
  
  
• Changes of environment (e.g., weather, altitude, time zone)
  
  
• Changes in habits (e.g., sleep patterns, skipping meals, overexertion)
  
  
• Smoking or exposure to second hand smoke
  
  
• Certain medications (e.g., nitroglycerin)
  
  
• Poor posture
  
  
• Poor vision (uncorrected farsighted or nearsighted vision)

There are also a number of less common causes. Secondary headaches may be a symptom of underlying conditions including:  

• Brain tumor
  
  
• Aneurysm (a bulge in a weakened blood vessel with the potential to burst)
  
  
• Stroke (an event in which blood flow to the brain is restricted) or transient ischemic attack (a “mini-stroke” in which oxygen to the brain is briefly interrupted)
  
  
• Head injury or other trauma, such as whiplash
  
  
• Temporal arteritis (inflammation of the temporal arteries)
  
  
• Encephalitis, meningitis or Lyme disease
  
  
• Trigeminal neuralgia (inflammation of the trigeminal nerve), other cranial neuralgias, or occipital neuralgia (neuropathy of the occipital nerve on the back of the scalp, causing pain from the back with radiation to the front of the head)
  
  
• Temporal arteritis (inflammation of the temporal arteries)
  
  
• Sinus inflammation (sinusitis)
  
  
• TMJ disorder
  
  
• Intracerebral hemorrhage (bleeding in the brain resulting from the rupture of a blood vessel in the head)
  
  
• Chronic pain disorders such as fibromyalgia, myofascial pain syndrome, chronic fatigue syndrome or lupus

The signs and symptoms associated with headaches vary by type of headache. They also vary from person to person and from headache to headache in the same patient.

The most common symptom of headache is pain. This pain may be mild, moderate or severe. The quality of the pain may also vary. Headaches may be described as intense, pounding, throbbing or steady. The location of the pain is another important characteristic. Pain may occur on one side of the head or both sides. It may be generalized and felt all over the head or be focused on certain areas. Frequency and duration may also vary.

In addition to pain, headaches may be associated with a number of other signs and symptoms, including:

• Nausea or vomiting
• Sensitivity to light or sound
• Temporary visual disturbances (aura)
• Fatigue
• Irritability or restlessness
• Excessive sweating
• Orofacial pain, jaw discomfort or dental pain
• Neck pain 
• Tenderness in the scalp, neck and shoulder muscles
• Insomnia (difficulty sleeping)
• Eye pain, redness, drooping eyelid, decreased pupil size, extreme tearing or swelling below or around the eyes  
• Rhinorrhea (runny nose) or nasal congestion
• Allodynia (pain from a normally nonpainful stimulus)
• Ear pain  

Many types of headache do not require medical attention. However, patients are encouraged to discuss all serious or recurring headaches with their physician and seek medical attention when a headache:

• Starts suddenly
• Is severe or persistent
• Does not improve with treatment
• Disturbs sleep
• Occurs with activity
• Changes in pattern or intensity
• Is accompanied by other symptoms, such as drowsiness, vision changes, changes in movement or sensation, changes in alertness, nausea and vomiting

In some cases head pain may indicate a more serious underlying condition such as a stroke, brain tumor or aneurysm. As a result, patients should seek emergency medical treatment when:

• A headache is accompanied by unusual symptoms not experienced with previous headaches including:
  
  
• Speech problems
• Vision abnormalities  (e.g., double vision)
• Numbness
• Weakness
• Fever
• Stiff neck
• Rash
• Seizures
• Mental confusion
• Loss of consciousness
  
  
• A headache occurs after a head injury
  
  
• A chronic headache intensifies with coughing, exertion, straining or sudden movement
  
  
• A new type of headache pain occurs (in those over age 50 or younger than 8)

Headaches that are mild to moderate in intensity, not accompanied by other symptoms and responsive to treatment within a few hours do not usually require medical attention. However, headaches that are severe, recurrent or chronic should be brought to a physician’s attention. Headaches that interfere with sleep, occur with activity or present with additional symptoms also require examination by a physician.    

During an evaluation for headache, physicians take the patient’s medical history and perform a physical examination. Information provided during the pain assessment can help physicians determine whether a patient’s symptoms are the result of a primary headache or an underlying medical condition, such as sinus infection or an aneurysm.

While obtaining a patient’s medical history, physicians may ask the patient about their symptoms. Questions may focus on the characteristics of the pain, including its severity, location, frequency, duration and accompanying symptoms. The most common headaches, including tension headaches, migraines and cluster headaches, are usually accompanied by characteristic symptoms. By collecting detailed information regarding the headache, physicians are often able to determine the type of headache. These questions also enable physicians to focus the physical examination and avoid any unnecessary tests.

The physical exam may include measurements of blood pressure and pulse, as well as inspection of the head, eyes, ears, nose, throat, neck, spine and shoulders. A neurological exam is also commonly performed to evaluate the nervous system. This evaluation may involve a number of tests including getting up from a seated position without support, and walking on the tips of the toes and heels, as well as motor, sensory, reflex and coordination tests. These evaluations are used to exclude a number of possible causes.

Physicians may order a number of diagnostic tests when they are unable to link headache symptoms with a specific headache syndrome, if symptoms of serious underlying conditions are present, or abnormalities are uncovered during the neurological examination. These tests also help physicians exclude a number of possible causes.

Diagnostic tests may include:  

• MRI (magnetic resonance imaging). MRIs use a powerful magnetic field to create images of structures and organs within the body, allowing a computer to produce clear cross-sectional or three-dimensional images. This test may be ordered to examine the brain and rule out aneurysm and a number of other serious causes.

• CAT scan (computed axial tomography). This test allows for multiple x-rays to be taken from different angles around the patient. A computer analyzes the "slices" or cross-sectional images. After the first set of images is taken, the patient may receive an intravenous (I.V.) injection of a contrast agent (dye) to better outline the body parts. Then a second set of images is taken. This test may be ordered to examine the brain and rule out aneurysm and a number of other serious causes.
  
  
• Blood tests. These may be performed to screen for infections and other potential causes of headache.
  
  
• Electroencephalogram (EEG). Electrodes are placed on the head to measure the brain’s electrical activity. This test may be performed to exclude seizures.
  
  
• Sinus x-ray. This procedure produces images of the sinuses (air-filled cavities in the frontal bones on the skull that are lined with mucous membranes). This test may be performed to exclude sinus inflammation (sinusitis) as a cause of headache.
  
  
• Spinal tap. Also known as a lumbar puncture, this procedure uses a needle to remove a sample of cerebrospinal fluid (CSF) from between vertebrae in the lower spine. Although this test is rarely required, it may be ordered to rule out meningitis, hemorrhage or other possible underlying conditions that can cause severe headaches.
  
  
• Temporal artery biopsy. This procedure requires removal of tissue from the affected artery. The sample is then examined. This procedure may be used to rule out temporal arteritis.  

In most people, headaches can be greatly controlled with a combination of lifestyle changes, headache medications and complementary therapies. These treatment plans vary from patient to patient. Patients are encouraged to schedule an appointment with a physician specifically to discuss their headaches, rather than trying to discuss them during an office visit scheduled for another reason.

A number of prescription and over-the-counter medications are used to treat headaches. The type of medication prescribed will usually depend on the characteristics of the headache, including its frequency and severity. A patient’s response to different medications, side effects and the patient's overall health are also taken into consideration.  

Drug therapy for headaches may include:

• Acute treatment. Also known as abortive treatment, acute treatment is aimed at stopping or reducing the pain of an existing headache. For maximum effectiveness, this type of treatment should be used at the first sign of a headache. Examples of medications used in acute treatment include:
  
  
• • Analgesics
  • Triptans
  • Dihydroergotamine
  • Decongestants (for sinus headaches)
    
    
  Oxygen administered through a breathing mask can also be used as a form of acute treatment.
  
  
• Preventive treatment. This type of treatment requires the daily use of medication to reduce the frequency and severity of headaches. Examples of medications used in preventive treatment include:
  
  
• • Beta blockers. These drugs decrease the workload of the heart and lower blood pressure.
    
    
  • Calcium channel blockers. These drugs increase the flow of oxygen–rich blood to the heart, lower blood pressure and reduce the workload of the heart.
    
    
  • Tricyclic antidepressants. These drugs are commonly used to treat depression. Antidepressants, however, may increase the risk of suicidal thinking and behavior in children and adolescents. As a result, the U.S. Food and Drug Administration (FDA) recommends that people being treated with these drugs be closely monitored for unusual changes in behavior.
     
  • Corticosteroids. These drugs are commonly used to relieve inflammation.
    
    
  • Lithium. A drug commonly used to treat bipolar disorder.
    
    
  • Ergot alkaloids. This group of drugs is used to treat a variety of conditions including headache.
    
    
  • Antihistamines. These drugs are commonly used to treat allergic reactions.
    
    
  • Indomethacin. This NSAID is commonly prescribed to relieve pain, tenderness, inflammation and stiffness.

Patients taking medications for headache should follow their physician’s dosing instructions carefully. Overuse of over-the-counter or prescription headache medication can cause analgesic rebound headaches and chronic headaches.  

Medications used to treat headaches have variable effectiveness in different people. In many cases, a number of medications may be tried before an effective drug, or combination of drugs, is found.

Patients should contact their physician when medications are not effective in relieving pain or when undesirable side effects develop. Physicians may choose to change the type of medication being used.

A number of other therapies may be used in conjunction with medication. These include:

• Cryotherapy (cold treatments)
• Relaxation techniques (e.g., meditation, progressive muscle relaxation, self-hypnosis)
• Physical therapy
• Cognitive behavioral therapy
• Biofeedback
• TENS or other electrical therapy
• Acupressure or acupuncture
• Nerve block (see Injection Therapy)

If other treatments fail, surgery may be an option in some cases, such as surgery on the sinuses for people suffering sinus headaches or migraines.

Recent research indicates that some populations may be undertreated for headaches, including men and adolescents. Anyone suffering from headaches is advised to take the initiative in seeking help.

Patients may reduce the frequency of headaches by avoiding factors that trigger the headaches. Patients may identify these triggers by keeping a headache diary. To compile this journal, patients record certain information after each headache occurs, including:

• When the headache occurred
• How severe the headache was
• Where the headache was located
• How long the headache lasts
• Additional symptoms experienced with the headache
• What was eaten before the headache occurred
• Sleep patterns and amount of sleep
• Menstrual cycles
• Medications taken prior to and after the headache
• Events prior to the headache (e.g., consumption of alcohol)

Some triggers, such as the hormone changes caused by menstruation or pregnancy, cannot be avoided. When medications are identified as the trigger, however, physicians are often able to find treatment alternatives.

Patients may also be able to reduce the frequency of headaches by making a few lifestyle changes, including:

• Avoiding cigarette smoking, caffeine and alcohol
• Exercising regularly
• Maintaining a nutritious diet
• Getting enough sleep and keeping a regular sleep pattern
• Practicing proper posture and ergonomics
• Using relaxation techniques such as progressive muscle relaxation or meditation 

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about headaches:

1. What may be causing my headaches?
   
   
2. How can I determine the cause of my headaches?
   
   
3. What symptoms may accompany my headaches?
   
   
4. Do I have a migraine, sinus headache, tension headache, cluster headache or some other type?
   
   
5. How can I relieve my headaches?
   
   
6. How can I prevent headaches?
   
   
7. What is the best over-the-counter drug for my headaches?
   
   
8. What other treatment might I need?
   
   
9. At what point should I call you or seek emergency treatment for a headache?
   
   
10. How many headaches are too many for my age?
    
    
11. Are some tests used for children to determine the cause of headaches?