What Is Headache? Symptoms, Causes, Diagnosis, Treatment, and Prevention

A person with a headache has discomfort or pain beneath the scalp or forehead, behind the eyes, or arising from the head or upper neck. While headaches may occur occasionally or frequently, they are still the most common nervous system disorder in the world. Evidence suggests that 52 percent of the global population is affected by a headache disorder every year, with 14 percent reporting migraine.

There are more than 150 types of primary and secondary headache disorders, according to the National Institute of Neurological Disorders and Stroke. Headaches can be the body’s reaction to emotional stress, grief, too much or too little sleep, or depression. Some people get a headache after physical exertion, crying, eye strain, or sex. Sometimes headaches are harmless and come and go in a matter of minutes, while other types of headache can be a symptom of a serious health problem.

Types of Headaches

Headaches may be primary or secondary, says Emad Estemalik, MD, a neurologist and the section head for headache and facial pain at the Center for Neurological Restoration at the Cleveland Clinic in Ohio.

“A primary headache is a headache that occurs independently and is not caused by another medical condition,” says Dr. Estemalik. “Secondary headache is when the head pain is being caused by another health issue; for example, a brain tumor would be a secondary cause of headache.” Secondary headaches are more concerning than primary headaches because they could be a sign of a more serious underlying health condition, he adds.

Migraine, cluster, and tension-type headaches are the most common types of primary headache. Secondary headaches can be caused by tumors, head injury or trauma, high blood pressure, fever, infection, or medication overuse.

Migraine

Many people use the words "migraine" and "headache" interchangeably, but a migraine attack is more than just a bad headache. Migraine is a neurological disorder that typically causes severe headaches but can also cause visual disturbances, nausea, vomiting, and extreme sensitivity to light, sound, touch, and smell along with head pain.

Migraine is very common; next to tension-type headache, it’s the most common type of headache. According to JAMA Network, in the United States over 17 percent of women and nearly 6 percent of men report having migraine symptoms.

It’s estimated that about 25 to 30 percent of people with migraine experience aura, which is described as a series of visual, sensory, or speech changes that occur shortly before the head pain hits. The American Migraine Foundation describes visual aura symptoms as including seeing lines or spots, sensory symptoms may include tingling or numbness in one or more areas of the body, and speech symptoms may include slowing and slurring of speech or difficulty understanding what others are saying.

Migraine pain is often described as throbbing and piercing. It generally occurs on one side of the head and lasts anywhere from 4 to 72 hours. Symptoms can include sensitivity to light and loud noises, nausea, and vomiting.

Learn More About Migraine

Tension-Type Headache (Also Called Stress Headache)

Tension-type headaches are the most common type of headache, and they tend to be milder than migraine attacks, says Katherine Hamilton, MD, of Medstar Health in Washington, DC.

“Tension-type headaches have different characteristics than migraines in that they tend to affect both sides of the head and involve a dull, pressure-type pain,” Dr. Hamilton says. Many people describe tension headaches as having a band squeezed around their head.

Tension-type headache can have a muscular component to the headache: The head and neck muscles can get a little bit tenser, says Estemalik. “Skull, head, and neck tenderness can happen in this type of headache,” he adds.

Cluster Headache and Other Trigeminal Autonomic Cephalalgias

Cluster headaches are relatively rare, affecting between 200,000 and 1 million Americans, according to the American Migraine Foundation. These headaches come in clusters (also known as cycles or periods) that can happen about once or twice a year and might last as long as a month, or even longer, per the University of Michigan Health. While technically not life threatening, these headaches cause such severe pain that some people contemplate suicide.

Cluster headache comes on suddenly, is almost always one-sided, and is associated with a piercing and very intense pain, says Kiran Rajneesh, MD, a pain medicine doctor and headache specialist at The Ohio State University Wexner Medical Center in Columbus.

The headaches generally last 15 minutes to 3 hours, often waking the person from sleep, with pain localized behind one eye or at the temple near the forehead; a runny nose and tearing on the side with the pain is also common.

Whereas people with migraine often retreat to a dark room to lie down, people with cluster headaches pace and can sometimes exhibit aggressive behavior, says Dr. Rajneesh. “Because the pain of a cluster headache is so severe, patients can become very agitated and restless,” he says.

The underlying cause of cluster headache is not known. Per the Mayo Clinic, cluster headache patterns indicate that they may be connected to abnormalities in the body’s biological clock, located in the hypothalamus, the area of the brain that produces hormones that control body temperature, heart rate, and appetite.

Other Primary Headache Disorders

In addition to migraine, tension-type headache, and cluster headache, the following are also primary headache disorders:

Primary Cough Headaches These headaches are brought on by coughing, sneezing, blowing your nose, laughing, crying, or straining. Primary cough headaches can be painful and disruptive, but they are harmless, resolve in 30 minutes or less, and are not caused by other head or brain conditions.

Primary Exercise Headache This type of headache occurs during or immediately after exercise. The pain is described as pulsing or throbbing on both sides of the head, and it can last for between 5 minutes and 48 hours, according to a review.

Primary Headaches Associated With Sexual Activity These headaches are brought on by sexual activity and can happen during or after sex, explains the American Migraine Foundation. They usually affect both sides of the head and are often located in the back of the head. They can be as short as one minute, but in some cases mild pain can linger for up to three days.

Primary Thunderclap Headache This is a very rare and severe form of headache that occurs abruptly, peaks within 30 seconds to a minute after onset, and then fades in the next few hours. StatPearls describes thunderclap headache as a secondary headache caused by intracranial vascular disorders; a thunderclap headache is usually only diagnosed as primary when all organic reasons have been ruled out.

Cold-Stimulus Headache This sudden-onset headache is more commonly known as a “ice cream headache” or “brain freeze.” According to Hackensack Meridian Health, it’s thought that the pain occurs when the cold substance hits the roof of the mouth or back of the throat and triggers a nerve response in the brain. A typical brain freeze lasts 30 seconds or less.

External-Pressure Headache This type of headache is caused by wearing tight hats, helmets, bands, or goggles. An article says that it is thought to happen because of continued stimulation of cutaneous nerves due to pressure on the scalp or forehead.

Primary Stabbing Headaches Also called ice pick headaches, these headaches cause severe, stabbing pain and typically last a few minutes or less, according to the American Migraine Foundation. In some cases, the pain occurs in the eyes.

Nummular Headache Also called coin-shaped headache, nummular headache comes with small circumscribed areas of continuous pain on the head. This can be a primary headache, but it can also be a secondary headache, caused by a malignant process in the brain, per StatPearls.

Hypnic Headache Also referred to as the “alarm clock headache,” the unique feature of hypnic headaches, according to the American Migraine Foundation, is that they develop only during sleep and they wake up the person experiencing them. This type headache occurs 10 days or more a month and typically lasts between 15 minutes and 4 hours.

New Daily Persistent Headache (NDPH) The name describes the key features of this headache, per a review: It develops in a person with no prior history of headaches, it occurs daily, and the pain is persistent and lasts for more than three months. One key feature of the headache is that people often clearly remember the date or even the time when the headache started. All potential causes must be ruled out before it is diagnosed as NDPH.

Secondary Headaches

Secondary headaches may be due to any of the following:

Trauma A post-traumatic headache (PTH) is a headache that develops within seven days of an injury or after regaining consciousness. Post-traumatic headache can be migraine like or tension-type; acute PTH resolves within three months, but persistent PTH can last much longer, according to a study.

Cranial or Cervical Vascular Disorders These headaches are related to blood flow in the brain and can be a major symptom of craniocervical vascular disease, such as a stroke. According to research, headaches caused by cranial or cervical vascular disorder usually come on quickly, are described as throbbing or thunderclap, peak rapidly, and sometimes don’t come with any other local symptoms or signs.

Nonvascular Intracranial Disorder These headaches can be a result of many different nonvascular (not related to the blood supply) disorders that impact the brain. Many of these conditions are described as idiopathic, meaning that it’s unclear what the cause is. Some of these headaches are caused by high or low cerebrospinal fluid pressure or noninfectious inflammatory diseases.

Headache Attributed to a Substance or Its Withdrawal Experts include among these headaches those caused by acute substance use or exposure; medication-overuse headache (previously called rebound headache), or headaches that are a side effect of chronic medication; and headaches caused by substance withdrawal (for example, opioids or caffeine).

Infection This type of headache causes moderate to severe pain and may be accompanied by fever, per Seattle Children’s. COVID-19 and the flu are viral infections that can cause headache. Meningitis is a very serious bacterial infection that can have headache as a symptom.

Disorder of Homeostasis Homeostasis is the concept that, according to an article, organisms adjust to external stimuli and surroundings so that internal conditions remain stable. Medical issues that disturb this balance may cause a headache, such as arterial hypertension or hypothyroidism, and external examples are high altitude or fasting.

Headache or Facial Pain Attributed to a Disorder of the Cranium, Neck, Eyes, Ears, Nose, Sinuses, Teeth, Mouth, or Other Facial or Cervical Structure This type of headache can include cervicogenic headaches or headaches caused by sinus infections. According to the International Headache Society, to be diagnosed as this type of secondary headache (rather than a primary headache), these headaches have to have evidence that they are specifically caused by the disorder or lesion.

Psychiatric Disorder Psychiatric conditions are highly prevalent among people with primary headache. Secondary headaches that are attributed to a psychiatric disorder occur only during a psychiatric disturbance, per a review.

Headaches can range from annoying to extremely painful. People may experience throbbing, squeezing, or constant or intermittent pain in the back of the head and upper neck or behind the eyes. Some people feel tightness or pressure at the temples.

Some headaches are excruciating. They feel like a poke in the eye, a stabbing in the brain, or a band of pressure around the head. Severe head pain can cause nausea and vomiting, according to the National Headache Foundation.

A headache commonly occurs alone but may coexist with other symptoms. Per the American Migraine Foundation, associated symptoms can be important clues for identifying the underlying cause of a headache.

Symptoms that may occur with headache include blurry vision, confusion, difficulty walking or speaking, excessive sleepiness, nausea, vomiting, fever, neck pain, neck stiffness, and increased sensitivity to light or noise.

Risk factors for primary headaches can include being born female, arterial hypertension, history of head trauma, and alcohol consumption, per a study.

“There are clear genetic predispositions for migraine. It’s very commonly seen in families,” says Anne Damian Yocoub, MD, codirector of the Johns Hopkins Headache Center in Baltimore.

Migraine is polygenic, which means that many genes appear to influence whether a person will develop the condition.

Even though people are born with some propensity for migraine, the condition has a threshold; people can reach that threshold when they are exposed to certain environmental factors or lifestyle changes, says Rajneesh. These can include certain foods or drinks, lack of sleep, or even changes in the weather, he says.

Secondary headaches can be caused by inflammation or irritation of structures that surround the brain or affect its function. They can also be caused by colds or the flu, fever, muscle stiffness in the head or neck area, dental or jaw pain, trauma to the head or neck, sinus infections, bleeding in the brain, or infections like encephalitis or meningitis.

Headaches can also be brought on by toxins, such as too much alcohol, smoking, or the consumption of allergenic or spoiled foods. Headaches can be the first sign of carbon monoxide poisoning or other environmental poisons, and they may be triggered by substance abuse or withdrawal.

Diagnosing what type of headache a person has can be complex, says Barbara Nye, MD, a neurologist and headache specialist at Atrium Health Wake Forest Baptist in Winston Salem, North Carolina. “We really focus on listening to our patients. Much of the information comes from the medical history, and so it’s really important for patients to reflect on how things have developed and the characteristics of their headache.”

It’s also worth noting that not every patient meets every piece of the diagnostic criteria every time, says Dr. Nye. “In those cases, we still treat them for the headache disorder that’s most appropriate,” she says.

The tests that your doctor orders will depend in part on what they suspect could be causing your headaches. The process of diagnosis may include the following:

Medical History Your doctor will want to know about other health conditions you have as well as any medications, supplements, or herbal treatments or teas that you rely on.

Family History You will be asked to provide details on any family members who have headaches or migraine attacks, at what age their headaches started, and any other health diagnoses they may have. Some types of headaches, such as migraine, have a genetic component, according to MedlinePlus.

Physical Exam Your doctor will examine you, paying close attention to your head, neck, and shoulders, all of which can be involved in headache pain.

Neurological Exam A neurological exam may include tests of your vision, hearing, nerves, reaction time, and mobility.

Blood and Urine Tests Blood and urine tests may be ordered to look for infection and other health conditions of which headaches are a symptom.

Spinal Fluid Test This may be necessary if your doctor suspects that your headaches are caused by certain types of infection or by bleeding in your brain.

Imaging Tests Computed tomography or magnetic resonance imaging may be ordered. These imaging tests can show changes in bones and blood vessels as well as the presence of cysts or growths that could be causing your headaches.

Neuroimaging Imaging tests may be performed during a headache episode to get a clearer picture of what is going on during an actual headache.

Electroencephalogram This test can show your doctor whether there are changes in brain wave activity. It can help diagnose brain tumors, seizures, head injury, and swelling in the brain.

Working closely with your family practitioner and, if needed, a neurologist will bring you closer to headache relief.

When Should You See a Specialist?

As a general rule, for nonsevere headaches, it is a good idea to first discuss your headaches with your primary care provider before seeking out a headache specialist. Approximately 2 out of 3 people talk to their primary care doctor first, according to the American Headache Society. However, if the recommended treatments are not working well or you have unusual symptoms, your doctor may refer you to a neurologist.

Possible signs that you may need to see a specialist for your headaches include:

• You have two or more headaches in a week. If your headaches come this frequently, you may need to add a preventive medication to your treatment plan, says Sandhya Kumar, MD, a neurologist and headache specialist at Atrium Health Wake Forest Baptist.
• Your headaches are getting worse, not better, with time and treatment. This may signal that you need further tests to make sure you’re properly diagnosed and on the right medications, says Dr. Kumar.
• Your headaches are not responding to recommended over-the-counter treatment or prescription drugs. Taking over-the-counter headache medication 10 days or more out of the month can put you at risk of developing medication-overuse headache (also called rebound headache). These hard-to-treat headaches are caused by taking too much pain-relieving medication, says Kumar.
• You are over 50 and having chronic headaches or a new type of headache. Being older than 50 when you develop headache puts you in a higher risk category for certain types of secondary headache, according to research.
• You have a new headache and a history of cancer or HIV/AIDS. This increases the risk that the headache is a caused by a brain tumor, per Memorial Sloan Kettering Cancer Center.
• Your headache began after you hurt your head. This could indicate post-traumatic headache, which may require different treatments than other types of headache, per StatPearls.
• You have a new headache that lasts 24 hours a day, 7 days a week. This could indicate a secondary headache that could be a sign of something more serious.
• Your headache is making it hard for you to carry out your daily life. If the pain is frequently keeping you from work or activities, you should check in with your doctor, says Kumar.

When Does a Headache Require Immediate Medical Attention?

Even though the majority of headaches aren’t life-threatening, there are cases in which a headache is a medical emergency. Per the Mayo Clinic, seek care for your headache right away if you experience any of the following:

• Your headache is accompanied by nausea, vomiting, dizziness, confusion, loss of consciousness, or blurry vision.
• Your headache is accompanied by weakness or loss of control of part of your body, speech, or vision. This could signal a stroke.
• Your headache is sudden and severe, and is accompanied by a stiff neck or fever. This could be meningitis, an inflammation of the brain usually caused by a viral infection.
• Your headache is the worst headache of your life. The abrupt onset of a very severe headache could mean bleeding or a clot in the brain.

How long a headache lasts depends on the type of headache it is. According to the National Institute of Neurological Disorders and Stroke, a thunderclap headache may last less than five minutes, whereas a headache known as hemicrania continua can last for months.

For some types of headache, such as a migraine, recognizing the cues and responding appropriately may reduce the duration of the headache, says Roderick Spears, MD, a clinical associate professor of neurology at Penn Medicine in Philadelphia. “Often the person with migraine doesn’t always recognize the prodrome phase [the warning signs of an oncoming migraine attack], but someone close to them — a spouse or family member — may pick up on it,” Dr. Spears says.

Spears offers a few tips to potentially reduce the length of your migraine attack:

• Aggressively hydrate. Drinking a lot of water is usually helpful.
• Limit your physical activity. If possible, sit or lie down somewhere.
• Avoid stimulating environments. Go to a dark, quiet place.

The key to getting effective treatment for a headache is identifying the underlying cause, per the Cleveland Clinic.

General treatment for a minor headache includes rest, stress reduction, cold compresses, massage to the temples and head area, and over-the-counter treatments such as acetaminophen (Tylenol) and nonsteroidal anti-inflammatory medications (NSAIDs), says Estemalik.

Treatments for Migraine

Medications for migraine and headache relief can be divided into two groups: pain-relieving (also known as abortive medications) and preventive (prophylactic medications).

Pain-relieving medications are taken once symptoms begin. These can include over-the-counter medications or those available by prescription, including triptans and NSAIDs, both of which can be taken as pills.

Two new classes of medications approved to treat acute migraine are gepants and ditans.

Preventive medications are taken regularly, sometimes daily, to stop migraine attacks before they start. Beta blockers (propranolol or timolol), anti-seizure drugs (topiramate), and some types of antidepressants can all be used to help prevent migraine attacks. Gepants have also been approved for preventive treatment of migraine.

Learn More About Migraine Treatments

Treatments for Tension-Type Headache

Tension-type headaches can be treated with over-the-counter medications such as aspirin, ibuprofen (Advil), or acetaminophen, or sometimes they don’t require treatment at all, says Hamilton.

Treatments for Cluster Headache

Acute treatment for cluster headache includes 100 percent oxygen therapy and injectable or nasal spray triptans. Oral triptans aren’t recommended because the time it takes for the medication to start working is often longer than the duration of the headache, according to StatPearls.

Nerve blocks can also be used in the prevention of cluster headaches, says Rajneesh. These in-office procedures can improve cluster headaches for a few weeks to a few months, he adds. Verapamil (Verelan), a calcium channel blocker, may also be used preventively for cluster headache.

Treating Other Trigeminal Autonomic Cephalalgias

Besides cluster headache, trigeminal autonomic cephalalgias include paroxysmal hemicrania, hemicrania continua, and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT syndrome).

Paroxysmal hemicrania may be treated with indomethacin (Indocin), which is a strong nonsteroidal anti-inflammatory.

SUNCT headache is rare, and according to the National Institute of Neurological Disorders and Stroke, most of the information that doctors have about treating them are through case studies, or in-depth studies of individuals or small groups of people. Corticosteroids and the anti-epileptic drugs gabapentin (Neurontin), lamotrigine (Lamictal), and carbamazepine (Tegretol) may help relieve some symptoms in some people with SUNCT headache.

Treatment Approaches for Secondary Headache Disorders

Whenever possible, the underlying cause of a secondary headache should be treated; for example, if the headache is caused by an infection, the infection should be treated, per the Sepsis Alliance.

Your doctor will recommend the best pain reliever to address your headache pain while the cause of the headache is being medically managed.

Prevention of Headache

Since it isn’t always clear what causes a headache, there’s no surefire way to prevent one from occurring, says Hamilton. But a few behaviors may reduce the number of headaches you have:

• Go to bed and wake up at about the same time every day.
• If you drink coffee, keep your intake consistent, and make sure it’s not interfering with your ability to sleep at night.
• Have regular meals at around the same time every day.
• Drink plenty of water throughout the day.

Hamilton also recommends that her patients with headache and migraine get regular exercise, since exercise can decrease stress, improve sleep, and improve mood.

“Physical activity can also have benefits if people have a lot of neck tension or tension-type headaches. Activities like yoga can help loosen up the muscles and help you relax,” she says.

If you can’t get out and run or walk, try to take advantage of the various free online resources for exercise to help you keep moving and keep a routine, suggests Hamilton. “I recommend a half hour or so of exercise at least five times a week if possible,” she says.

Headaches can have both physical and psychological consequences for those who experience them.

Mental Health Disorders Some types of headaches are associated with higher rates of anxiety, depression, and post-traumatic stress disorder (PTSD), says Dr. Nye. “However, it would be an oversimplification and inaccurate to say, 'Because I have anxiety, I have migraine,' or vice versa,” she adds. “There is a relationship, but one doesn’t necessarily cause the other.”

If one condition isn’t treated, it may cause the other disorder to flare, says Nye. “So people whose depression, anxiety, or PTSD is poorly addressed often have a hard time managing their headache symptoms.”

Stroke Risk People who have sensory symptoms with migraine, such as numbness and tingling, should definitely see a neurologist to make sure there’s not another neurologic condition going on, says Nye. “People who experience migraine with a sensory aura are at a twofold higher risk of stroke over their age-matched population,” she says.

Higher Rate of Suicide There is a higher rate of suicide in people who have cluster headaches, says Nye. These headaches not only cause intense pain but there is often a delayed diagnosis, so they aren’t being properly treated, she says.

Prognosis of Headache

The prognosis depends on the headache type and multiple factors, says Nye. “A primary headache, such as a tension-type headache or migraine, impacts quality of life, but I’m not aware of any data that would indicate that they would shorten lifespan in any way,” she says.

The prognosis of a secondary headache would depend on the condition causing the headache, she says. “In general, in secondary headaches, if the cause of the headache is identified and treated, that headache type should go away,” she says.

It’s estimated that 95 percent of the general population have experienced a headache at some stage in their life.

The 2018 National Health Interview Survey reported that 20.1 percent of women and 10.6 percent of men experienced a severe headache or migraine within the past three months. For both men and women, the number of people experiencing severe headache or migraine declined with age.

It’s estimated that 98 percent of headache disorders are primary headaches, with tension-type headache being the most common type of primary headache. Migraine also very prevalent: It’s estimated that close to 37 million people in the United States alone have migraine, says Nye.

People living with headache or migraine can benefit from reliable resources offering information and support. Many organizations provide educational materials and can assist in finding doctors specializing in headache and migraine care. There are also online communities that offer support as well as practical advice and tips.

American Migraine Foundation

This nonprofit organization strives to connect people with migraine with the care and support they need. The website features a doctor-locator tool and guidance on a range of issues, including managing migraine at work, identifying types of headaches, applying for Social Security disability income, and handling emergency room visits related to migraine.

Coalition for Migraine and Headache Patients

The stated mission of this nonprofit is “to improve the lives of people with migraine, cluster, and other headache diseases by aligning coalition participants and empowering patient voices.” The organization provides resources about disease, treatment, and health insurance as well as tools to help find a specialist.

National Headache Foundation

This organization aims to cure headache and to end the pain and suffering it causes through awareness, advocacy, education, and research. The website offers resources on all different types of headache for both patients and providers.

Learn More About Headache and Migraine Resources

Additional reporting by Brian Joseph Miller.