Headache: types, causes, symptoms, and when to worry

Headache is one of the most common health problems on the planet, and you have probably had one this week or know someone who has. According to the World Health Organization (WHO), headache disorders affect about 40% of the population, the equivalent of 3.1 billion people in 2021, which places them among the most frequent disorders of the nervous system. The good news is that, in the vast majority of cases, the pain is benign and passing. The news that few people know is that there are well-defined types, with different triggers and different ways of managing them, and that recognizing your type is the first step toward suffering less.

This guide was built to be a complete reference: you will understand what a headache is, how to tell the main types apart, why it happens, which triggers to avoid, how it is diagnosed, what treatment approaches exist, and, above all, the few warning signs that call for immediate medical attention. All of it is based on official sources such as the WHO, MedlinePlus (from the United States National Library of Medicine), and the NHS (the United Kingdom National Health Service).

What a headache is

A headache is the name given to any pain located in the head or the upper part of the neck. Even though we feel the pain "in the head," the brain tissue itself does not hurt, because it has no pain receptors. What hurts are the structures around it: the muscles of the skull, neck, and shoulders, the blood vessels, the nerves of the face and scalp, and the membranes that line the brain. When one of these structures is stimulated, by muscle tension, changes in the vessels, or inflammation, the result is the pain we know.

A headache can arise on its own, with no other disease behind it, or it can be the reflection of a passing situation, such as a poor night of sleep, the flu or a cold, prolonged fasting, or dehydration. This difference is so important that medicine divides headaches into two large groups, which we will see next.

Primary and secondary headache: the divide that changes everything

Before talking about specific types, it is worth understanding this classification, because it guides both the treatment and the level of concern.

Primary headache is the one in which the headache is the problem itself, and not the symptom of another disease. This is where the most common types fall: tension-type headache, migraine, and cluster headache. They are responsible for the overwhelming majority of headaches and, although they can be very bothersome, they generally do not indicate a risk to life.

Secondary headache is the pain that appears as a consequence of another condition. The most common example, according to the WHO, is medication-overuse headache. But the list of secondary causes is long and ranges from simple situations, such as a sinus infection or a cold, to rare and serious conditions, such as infections, bleeding, or increased pressure inside the skull. It is precisely to identify the dangerous secondary causes that the warning signs described further on exist.

The main types of headache

Most headaches fit into a few well-recognized patterns. Knowing how to identify yours helps you find relief faster and know what to discuss with your doctor.

Tension-type headache

This is the most common type of headache. People usually describe a feeling of pressure or tightness on both sides of the head, as if a band were squeezing the skull. The intensity is generally mild to moderate, and the pain does not usually worsen with day-to-day physical activity. According to the WHO, the episodic form, which occurs on fewer than 15 days per month, is reported by more than 70% of people in some populations, and it affects about 50% more women than men.

Tension-type headache is closely linked to stress, anxiety, and tension in the muscles of the neck, shoulders, scalp, and jaw. Poor posture, many hours in front of a screen, and poor nights of sleep tend to feed this type of pain.

Migraine

Migraine is a more intense and disabling primary headache. The WHO describes it as recurrent attacks of moderate to severe pain, often on one side only or behind the eye, with a pulsating quality (it seems to throb). The attacks last from 4 to 72 hours when untreated and usually come with nausea, vomiting, and strong sensitivity to light (photophobia) and sound (phonophobia). The pain tends to worsen with physical effort, which leads many people to prefer lying down in a dark and quiet place.

Migraine usually begins at puberty and mainly affects people between 35 and 45 years of age, being more common in women. MedlinePlus estimates that about 12% of people have migraine, and that women are about three times more likely to have it than men, which points to the role of hormonal changes.

Cluster headache

This is a relatively rare type that affects fewer than 1 in every 1,000 adults, according to the WHO, and is more common in men (about six men for every woman). The attacks are short but extremely intense, concentrated around one of the eyes, and they can recur several times a day during periods called "clusters." Because of its intensity and pattern, it is a pain that always deserves specialist evaluation.

Medication-overuse headache (rebound headache)

This type deserves to be highlighted because it is common and, at the same time, little known. When a person uses pain medicines very often, the pain reliever itself begins to feed a cycle of headaches. The WHO notes that this medication-overuse headache can affect up to 5% of people in some populations, with a predominance in women. MedlinePlus links the problem to using pain medication on more than three days per week. It is a clear example of how "treating" the pain the wrong way can make it worse, and that is why frequent use of pain relievers should always be evaluated by a professional.

Other common causes of headache

Beyond the types above, several everyday situations cause secondary and passing headaches, such as colds and flu, sinus infections, a sore throat with a cold, uncorrected vision problems, headaches related to hormonal changes (such as the menstrual period or menopause, often part of PMS), and pain linked to straining, coughing, or physical activity. The NHS also lists poor posture, dehydration, and skipping meals among the frequent causes.

Comparison table of the main types

Feature	Tension-type headache	Migraine	Cluster headache
Location	On both sides, in a band	Usually on one side	Around one of the eyes
Type of pain	Pressure, tightness	Pulsating, throbbing	Stabbing, very intense
Intensity	Mild to moderate	Moderate to severe	Extremely severe
Duration	From hours to a few days	From 4 to 72 hours	Short attacks, repeated during the day
Worsens with effort	Generally no	Yes	Attack is intense on its own
Associated symptoms	Muscle tension	Nausea, sensitivity to light and sound	Red and watery eye, blocked nose
Who is most affected	More common in women	About 3 times more in women	More common in men

The four phases of a migraine

One of the reasons migraine is so distinctive is that it tends to happen in phases. Not everyone goes through all of them, and they vary from one attack to another, but knowing them helps you anticipate and manage them better. MedlinePlus describes four possible phases:

1. Prodrome: begins up to 24 hours before the pain. There may be subtle signs such as mood changes, cravings for certain foods, yawning, or an increased need to urinate.
2. Aura: happens in some people. These are temporary neurological symptoms, most often visual, such as seeing flashing lights, bright spots, or zigzag lines. There may also be tingling or muscle weakness.
3. Headache (the pain): the pain phase itself, which usually starts gradually and becomes stronger, throbbing, and often on one side, with sensitivity to light, sound, and smells, along with nausea.
4. Postdrome: after the pain passes, it is common to feel tired, weak, and to have trouble concentrating for up to a day, in what many people call a "migraine hangover."

Why a headache happens: causes and mechanisms

There is no single cause for headaches, because each type has a different mechanism. In tension-type headache, the lead role is played by tension in the muscles of the neck, shoulders, and scalp, often brought on by stress, anxiety, and posture. In migraine, the mechanism is more complex and involves an increased sensitivity of the nervous system and the participation of nerves and substances that cause inflammation and pain around the brain's vessels, with a strong genetic and hormonal influence.

Secondary headaches, on the other hand, have their cause in the condition behind them: the pressure of inflamed sinuses in a sinus infection, the fever and inflammation of a cold, the visual strain of an uncorrected refractive error, and so on. A sinus infection that turns out to be bacterial may, in some cases, need antibiotics, a decision that belongs to the doctor. Understanding the mechanism matters because it explains why different measures work for different types of pain.

The most common triggers

A trigger is what sets off an attack in someone who is already predisposed. Identifying and reducing your triggers is one of the most effective strategies for lowering how often the pain appears. Among those most cited by official sources are:

• Stress, anxiety, and muscle tension
• Insufficient, excessive, or irregular sleep, including insomnia
• Skipping meals and prolonged fasting
• Dehydration (drinking too little water), so good hydration helps
• Alcohol consumption
• Excess caffeine, or its sudden withdrawal
• Hormonal changes, such as the menstrual period
• Sensory stimuli, such as very bright lights and loud noises
• Changes in weather and routine
• Tobacco
• Certain foods, in sensitive people, such as chocolate, aged cheeses, and processed meats
• Overuse of pain medicines

An important note about food and caffeine is worth making: triggers are individual. What sets off pain in one person may have no effect at all on another. For this reason, more useful than cutting out everything on the list is discovering your personal triggers, and the best tool for that is the headache diary, explained further on.

Headache by region: what each location tends to indicate

Many people want to understand what pain at a specific spot means. The location helps, but it never confirms the diagnosis on its own. Here are the most common patterns:

• Pain on both sides, in a band around the head: the classic pattern of tension-type headache.
• Pain on one side only, throbbing: common in migraine, although it also appears in other types.
• Pain around one of the eyes, very intense: the typical pattern of cluster headache.
• Pain in the forehead and face, with a feeling of pressure: may be linked to a sinus infection, especially when there is nasal congestion and it worsens when bending the head down.
• Pain at the back of the head and the nape of the neck: often linked to muscle tension and posture. However, a sudden, explosive pain at the back of the head is a warning sign and requires immediate care.

When a headache is an emergency: warning signs

This is the most important section of the guide. The vast majority of headaches are not dangerous, but there is a small group of situations in which the pain can be a sign of something serious. Bringing together the guidance from the NHS and MedlinePlus, seek immediate medical care (an emergency room or emergency service) if a headache comes with any of these signs:

• Sudden and very severe pain, described as the worst of your life, that peaks within seconds or a few minutes
• Pain that starts after a blow or trauma to the head
• A stiff neck accompanied by high fever
• Mental confusion, excessive drowsiness, or difficulty waking up
• A seizure
• Weakness or numbness on one side of the body, difficulty speaking or understanding
• Loss of vision, double vision, or persistent visual changes
• Difficulty with balance or walking
• Severe pain in one eye, with redness
• Skin spots that do not fade when pressed, together with fever

Beyond the emergencies, there are signs that call for an appointment without extreme urgency, but without putting it off, as the NHS and the WHO point out: headaches that become frequent or more intense over time, that clearly worsen when coughing, sneezing, bending over, or straining, that come with jaw pain when chewing or tenderness in the scalp, or that change pattern in people over 50 years of age. Repeated vomiting along with the pain also deserves evaluation.

The central message is simple: a headache with new neurological symptoms, explosive pain, or pain that changes pattern should not be managed at home. When in doubt, seek help.

How the diagnosis is made

There is no single test that diagnoses most headaches. According to MedlinePlus, the diagnosis of primary headaches is essentially clinical, that is, based on the patient's history and on the physical and neurological examination. The doctor usually asks about the location of the pain, the type (pressure, throbbing), the intensity, the duration, the frequency, the associated symptoms, what makes it better and what makes it worse, and the possible triggers. For this reason, arriving at the appointment with this information organized speeds up the diagnosis a great deal.

Imaging tests, such as a CT scan or an MRI, are not necessary in most cases of common headache. They are usually requested when there are warning signs, when the pain changes pattern, or when the doctor suspects a secondary cause. Blood tests, such as a complete blood count, can also be ordered in specific situations. The decision to request each test or not belongs to the professional evaluating the case.

Treatment and management approaches

The treatment of a headache depends on the type, the frequency, and the impact on the person's life, and it should be defined by a health professional. In general terms, the approaches fall into two large groups.

Treatment of attacks (acute): aims to relieve the pain when it appears. It can include non-medication measures, such as resting in a calm and dark place, and the use of medicines. For migraine, MedlinePlus mentions classes of medicines specific to attacks, in addition to common pain relievers, and it reinforces a practical point: the earlier the treatment of the attack is started, the more effective it tends to be. Important: the choice and use of any medicine, including doses and frequency, are the responsibility of the doctor, and using it on your own and in excess can lead to rebound headache.

Preventive treatment: aimed at people who have frequent or very intense attacks, it seeks to reduce the frequency and severity over time. It mainly includes lifestyle changes (regular sleep, hydration, stress control, physical activity) and, in selected cases, continuous-use medicines prescribed and monitored by a doctor. Some people also turn to complementary approaches, but any supplement or therapy should be discussed with a professional before starting, and it does not replace medical evaluation.

Evidence-based prevention and self-care

For mild and occasional episodes, and as support for prevention, simple lifestyle measures make a real difference. Official sources converge on the following guidance:

• Stay well hydrated. Drinking water throughout the day is one of the NHS self-care recommendations, and dehydration is a common trigger.
• Sleep on a regular schedule. Both too little and too much sleep can set off pain. Consistent times help.
• Do not skip meals. Prolonged fasting is a frequent trigger.
• Manage stress. Since stress feeds tension-type headache and migraine, relaxation techniques, breaks, and physical activity help.
• Take care of your posture and screen breaks. Long periods in the same position strain the neck and shoulders.
• Go easy on alcohol and caffeine. Both, in excess, are known triggers; a caffeine-free warm drink such as ginger tea with lemon can be a soothing alternative.
• Avoid turning the pain reliever into a habit. Using pain medicine on many days of the month is the path to rebound headache.

The headache diary: your most powerful tool

Among all the strategies, the headache diary is one of the most recommended and most underestimated. The idea is simple: record each attack, noting the day and time, the intensity, what you ate, how you slept, what you were doing beforehand, and how long it lasted. With a few weeks of records, patterns begin to emerge, and it becomes much easier to identify personal triggers and assess what is working. This diary is also valuable information to bring to your appointment.

Headache in specific situations

Some situations deserve their own attention, always with the understanding that each case should be evaluated individually by a professional:

• In pregnancy: hormonal changes can alter the pattern of the pain. Since the use of medicines during pregnancy has restrictions, any medicine should be guided by the doctor following the pregnant patient.
• In children: a headache that gets worse, that disrupts sleep, or that comes with other symptoms deserves evaluation, according to the NHS.
• After age 50: the appearance of a new type of headache, or the clear change of an old pattern, is a sign that deserves investigation.
• On waking or one that wakes the person at night: pain that always appears in this pattern should be mentioned to the doctor.

Myths and facts about headaches

"Every severe headache is a migraine." Myth. Intensity alone does not define the type. The full set of features (side, type of pain, duration, and associated symptoms) is what tells them apart.

"If I take plenty of pain relievers, I will solve it for good." Myth, and a dangerous one. Overusing pain medicines can cause rebound headache and make the problem chronic.

"Drinking water helps relieve a headache." True in many cases. Dehydration is a common trigger, and staying hydrated is official self-care guidance.

"Headaches can be hereditary." True, especially in migraine, which has a strong genetic and family component.

"Every headache needs an imaging test." Myth. Most do not. CT scans and MRIs are reserved for warning signs or suspicion of a secondary cause.

What to bring and ask at the appointment

To make the most of the medical evaluation, go prepared. Bring, if possible, your headache diary and have in mind answers to questions such as: how long ago the pain began, how often it appears, in what part of the head it hurts, what type of pain it is, how long it lasts, what seems to trigger it, what relieves it, which medicines you have already used and how often, and whether there are cases of migraine in the family. Useful questions to ask the doctor include: what type is my headache, do I need any test, what changes in habits could help in my case, and which signs should make me come back urgently.

Summary: what to take from this guide

Headache is common and, most of the time, benign. The most frequent types are tension-type headache (pressure on both sides) and migraine (throbbing pain, on one side, with nausea and sensitivity to light). Identifying your type, knowing and reducing your triggers, keeping healthy habits, and using pain relievers sparingly are the foundations of self-care. The non-negotiable point is recognizing the warning signs: sudden and explosive pain, pain after trauma, or pain accompanied by fever with a stiff neck, confusion, weakness, or changes in speech or vision call for immediate care. And, because effective treatments exist, frequent headaches or ones that get worse over time deserve to be investigated. The WHO itself reminds us that most people with headaches still do not receive a proper diagnosis and treatment, so seeking guidance is, very often, the step that is missing in order to live with less pain.