Headaches are extremely common. They can happen after a stressful day, poor sleep, dehydration, an illness, prolonged screen time, or a migraine attack. In most cases, a headache is not caused by a dangerous medical condition.

However, some headaches are warning signs of problems that require urgent or emergency evaluation. A headache that begins suddenly and reaches severe intensity quickly, occurs after a significant head injury, or happens with weakness, difficulty speaking, confusion, fever and neck stiffness, loss of consciousness, or major vision changes should not simply be treated at home.

The important question is therefore not just “Why does my head hurt?” but:

When is a headache something you can monitor at home, when should you visit urgent care, and when should you go directly to the emergency room?

This guide explains common causes of headache, features that can distinguish migraine and tension-type headaches, warning signs of potentially serious conditions, and how healthcare professionals evaluate a concerning headache.¹˒²

Medical disclaimer: This article is for general educational purposes and does not provide an individual diagnosis or replace evaluation by a qualified healthcare professional. If you are experiencing severe, sudden, unusual, or rapidly worsening symptoms, seek appropriate medical care.

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What Causes Headaches?

A headache is pain or discomfort involving the head, scalp, or neck. There are many possible causes, ranging from primary headache disorders such as migraine to headaches that occur because of another illness or medical condition.¹

Some of the more common possibilities include:

• Tension-type headache
• Migraine
• Viral illnesses
• Sleep deprivation
• Stress
• Skipped meals
• Medication effects
• Caffeine withdrawal
• Neck and muscle tension
• Sinus or upper respiratory symptoms
• Cluster headache

Less commonly, headache can result from a serious secondary cause such as bleeding around the brain, stroke, meningitis, significantly increased intracranial pressure, acute glaucoma, or another neurological or vascular disorder.²

The characteristics of the headache—and especially the symptoms occurring with it—help determine how urgently it needs to be evaluated.

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What Does a Tension Headache Feel Like?

Tension-type headaches are among the most common types of headache.

They frequently produce a dull, aching, squeezing, or pressure-like sensation rather than the pulsating pain commonly associated with migraine. The discomfort may occur on both sides of the head and can feel like pressure around the forehead or a tight band around the head.¹

Tension headaches can also be associated with tightness or soreness involving the:

• Neck
• Shoulders
• Scalp
• Jaw

Stress, inadequate sleep, missed meals, and prolonged positioning may contribute to headaches in some people.¹

For example, someone who spends many hours working at a computer may develop neck and shoulder tension followed by a dull headache later in the day.

A typical mild tension headache without neurological symptoms or other warning signs is usually much less concerning than a sudden, severe, unfamiliar headache.

However, don’t automatically assume that every pressure-like headache is a tension headache. A significant change from your normal headache pattern deserves medical attention.

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What Does a Migraine Feel Like?

Migraine is more than simply a severe headache. It is a neurological condition that can cause recurring attacks involving head pain and other symptoms.

Migraine commonly causes moderate to severe throbbing or pulsating pain, often affecting one side of the head. Associated symptoms may include:

• Nausea
• Vomiting
• Sensitivity to light
• Sensitivity to sound
• Sensitivity to smells
• Fatigue
• Difficulty functioning normally

Migraine attacks can last from hours to days.³

Some people also experience migraine with aura.

Aura commonly causes temporary visual symptoms such as:

• Spots
• Zigzag patterns
• Flashing or sparkling lights

Aura can also involve sensory symptoms such as tingling or changes in speech.³

If you’ve never experienced these neurological symptoms before, however, you should not automatically assume they are migraine aura. New speech difficulty, weakness, major visual changes, confusion, or other neurological deficits require prompt assessment because conditions such as stroke can produce neurological symptoms as well.

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Headache Behind One Eye: Should You Worry?

Bing’s search data shows that people frequently search for “headache behind right eye,” so this deserves particular attention.

Pain behind or around one eye can have several causes.

Migraine can produce pain involving one side of the head and the area around an eye. Cluster headaches can also cause extremely severe one-sided pain around the eye.

Other possibilities include sinus-related symptoms, eye strain, and various ophthalmologic or neurological conditions.

The important distinction is whether the headache is accompanied by warning signs.

Severe pain involving one eye accompanied by a red eye requires prompt medical attention, particularly if there are visual changes, nausea, vomiting, or significant eye pain.²

Certain eye emergencies can produce headache-like pain and threaten vision if treatment is delayed (also see eye redness and when to worry).

Do not assume that severe pain behind an eye is simply a migraine if the symptoms are new or substantially different from previous headaches.

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When Is a Headache Serious?

Most headaches are not emergencies. What matters is identifying patterns that raise concern for a secondary cause.

A headache deserves greater concern when it is:

• Sudden and extremely severe
• The first severe headache you’ve experienced
• Dramatically different from your usual headaches
• Progressively worsening
• Associated with neurological abnormalities
• Associated with high fever and neck stiffness
• Associated with loss of consciousness or confusion
• Following significant head trauma
• Associated with severe eye pain or major vision changes
• New in someone with certain significant underlying medical conditions

A person’s age, medical history, medications, pregnancy status, immune status, cancer history, and recent events can also affect how clinicians evaluate a new headache.²

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What Is a Thunderclap Headache?

A thunderclap headache is a severe headache that begins abruptly and reaches very high intensity rapidly.

People sometimes describe it as:

• “The worst headache of my life”
• A headache that came out of nowhere
• An explosive headache
• An instantly severe headache

A sudden, explosive headache requires emergency evaluation because one important cause is subarachnoid hemorrhage, or bleeding into the space surrounding the brain.

There are other potential causes of sudden severe headache as well.

The American College of Emergency Physicians specifically addresses evaluation for subarachnoid hemorrhage in adults presenting with acute headache because rapidly identifying this condition can be critical.⁴

A sudden severe headache should not be treated at home simply to “see if it goes away.”

If your headache is abruptly severe or substantially different from anything you have experienced before, seek emergency medical evaluation.

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Headache With Weakness, Numbness, or Trouble Speaking

This combination is particularly concerning.

Seek emergency medical care if a headache occurs with new:

• Weakness of an arm or leg
• Facial weakness or drooping
• Numbness
• Difficulty speaking
• Slurred speech
• Difficulty understanding speech
• Loss of balance
• Significant coordination problems
• Confusion
• Major vision changes

These symptoms can indicate an acute neurological problem, including stroke or intracranial bleeding.²

Do not drive yourself if you are experiencing symptoms suggesting a stroke or other major neurological emergency. Emergency medical services can begin assessment and treatment while transporting you.

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Headache With Fever and Stiff Neck

Headache can occur during ordinary viral illnesses, particularly when fever, congestion, fatigue, and body aches are present.

However, the combination of significant headache, fever, and neck stiffness deserves particular attention because meningitis is one possible cause.²

Meningitis involves inflammation of the tissues surrounding the brain and spinal cord.

Depending on the cause and presentation, other symptoms can include:

• Nausea
• Vomiting
• Light sensitivity
• Confusion or altered mental status
• Significant lethargy
• Seizures

Not every person with meningitis has every classic symptom.

If someone has a severe headache accompanied by high fever, stiff neck, confusion, altered consciousness, or significant systemic illness, emergency evaluation is appropriate.²

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Headache With Nausea or Vomiting

Nausea and vomiting are common during migraine attacks, so their presence does not automatically indicate an emergency.³

However, context matters.

A familiar migraine accompanied by nausea in someone with an established migraine pattern is different from a new severe headache with repeated vomiting, neurological abnormalities, fever and neck stiffness, or a recent head injury.

Repeated vomiting can also contribute to dehydration (also see nausea and vomiting and when to worry).

Seek medical evaluation if vomiting prevents you from keeping down fluids, especially when accompanied by worsening headache or other concerning symptoms.

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Headache After a Head Injury

Headache commonly occurs after minor head trauma, but certain symptoms following a head injury require urgent evaluation.

Seek immediate medical attention after a head injury if there is:

• A headache that progressively worsens or does not resolve
• Repeated vomiting
• Seizure
• Difficulty waking up
• Weakness or numbness
• Slurred speech
• Loss of coordination
• Increasing confusion, agitation, or unusual behavior
• Loss of consciousness
• Significant neurological changes

These symptoms can indicate a more significant traumatic brain injury or intracranial bleeding.⁵

Risk may also be different for someone taking anticoagulant medications or with certain bleeding disorders.

Do not dismiss a progressively worsening headache after head trauma merely because the person initially seemed well.

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Why Do I Have a Headache Every Day?

Another search pattern identified in Bing’s data is “headaches everyday.”

Frequent headaches deserve evaluation because there are many possible explanations.

These can include:

• Frequent tension-type headaches
• Migraine
• Sleep problems
• Medication effects
• Caffeine-related headaches
• Chronic neck or musculoskeletal problems
• Vision-related issues
• Other medical conditions

Another important possibility is medication-overuse headache.

Taking certain acute headache medications too frequently can contribute to recurring headaches. MedlinePlus recommends discussing headaches with a healthcare professional when pain medicines are required frequently, and NINDS notes that preventive strategies may be appropriate for some people with frequent migraine attacks.¹˒³

If you are having headaches repeatedly, don’t simply continue increasing your use of over-the-counter pain medication without discussing the pattern with a healthcare professional.

A headache diary can be useful.

Record:

• Date and time
• Duration
• Location of pain
• Pain severity
• Associated symptoms
• Sleep
• Meals
• Caffeine
• Menstrual cycle if relevant
• Medications taken
• Possible triggers
• What relieved the headache

Patterns in this information can help a clinician distinguish between different headache disorders and select appropriate treatment.³

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Can Dehydration Cause a Headache?

Headaches can occur when someone has not been drinking adequately, particularly when fluid loss occurs through vomiting, diarrhea, heat exposure, or strenuous activity.

Other possible symptoms of dehydration can include:

• Thirst
• Dry mouth
• Dizziness
• Weakness
• Reduced urination
• Darker urine

If headache occurs with vomiting or diarrhea, maintaining hydration becomes particularly important.

However, severe or unusual headache should not automatically be attributed to dehydration simply because you haven’t consumed much water (also see dizziness and when to worry).

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Can Sinus Problems Cause Headaches?

Upper respiratory illnesses and sinus inflammation can cause facial pressure or discomfort that people describe as a headache.

Symptoms suggesting an upper respiratory or sinus component may include:

• Nasal congestion
• Facial pressure
• Nasal drainage
• Reduced sense of smell
• Cough
• Pressure around the cheeks or forehead

However, not every headache with facial pressure is a bacterial sinus infection, and antibiotics are not appropriate for every sinus-related headache.

Some migraine attacks can also be mistaken for “sinus headaches.”

If headache is accompanied by significant neurological symptoms, sudden severe onset, confusion, or other red flags, a more serious cause needs to be considered regardless of whether congestion is also present.

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Can Coughing Make a Headache Worse?

Some people experience headaches that are triggered or worsened by coughing, sneezing, straining, bending over, or other activities that temporarily alter pressure.

There are benign primary cough headaches, but a new headache consistently triggered by coughing or exertion can sometimes require medical evaluation to exclude a secondary cause.

This is particularly important when the headache:

• Is new
• Is severe
• Begins abruptly
• Is progressively worsening
• Occurs with neurological symptoms
• Occurs with vomiting or visual abnormalities

A clinician may determine whether additional evaluation or imaging is appropriate based on the patient’s age, examination, history, and headache characteristics (also see persistent cough).

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Can High Blood Pressure Cause Headaches?

People frequently attribute headaches to elevated blood pressure, but the relationship is more complicated than simply “my blood pressure is high, therefore it caused my headache.”

Pain, stress, anxiety, illness, and other factors can temporarily elevate blood pressure.

Extremely elevated blood pressure accompanied by evidence of acute organ injury is a different situation and can constitute a hypertensive emergency.

A severe headache occurring with very high blood pressure plus symptoms such as:

• Neurological deficits
• Confusion
• Significant vision changes
• Chest pain
• Severe shortness of breath

requires urgent medical assessment (also see chest pain and when to worry)

Do not rely on headache severity alone to determine whether a blood-pressure reading is dangerous.

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Headache With Chest Pain or Shortness of Breath

Headache itself usually does not explain significant chest pain or breathing difficulty.

If these symptoms occur together, clinicians consider the entire presentation rather than assuming they are all part of a benign headache.

New chest pain or significant shortness of breath can independently require urgent or emergency evaluation (also see shortness of breath and when to worry).

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When Should You Go to Urgent Care for a Headache?

Urgent care may be appropriate when a headache needs medical evaluation but there are no obvious emergency warning signs.

Examples may include:

• Persistent headache that isn’t improving
• A suspected migraine without emergency features
• Tension-type headache that is not responding to usual measures
• Headache associated with a minor illness
• Headache associated with sinus or upper respiratory symptoms
• Recurring headaches requiring evaluation
• Mild-to-moderate headache with a reassuring neurological status

Urgent care clinicians can obtain a medical history, check vital signs, perform a neurological examination, assess hydration, evaluate for infections or other causes, and provide treatment when appropriate.

However, urgent care centers vary considerably in their capabilities.

If the clinician believes that emergency neuroimaging, lumbar puncture, specialist evaluation, or hospital-level monitoring is necessary, you may be sent to an emergency department.

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When Should a Headache Go Directly to the ER?

**Go to the emergency department or seek emergency assistance for a headache with features such as:**²

• Sudden, explosive onset
• “Worst headache of my life”
• New weakness, paralysis, or numbness
• New difficulty speaking
• New major vision abnormalities
• Confusion or significant altered mental status
• Loss of consciousness
• Seizure
• High fever with significant neck stiffness
• Severe headache after significant head trauma
• Severe eye pain with redness or significant vision changes
• Rapidly worsening severe headache
• A first severe or highly unusual headache, particularly when accompanied by other concerning symptoms

Some patients also warrant a lower threshold for evaluation because of their medical history, age, pregnancy/postpartum status, immunosuppression, cancer, anticoagulant use, or other clinical circumstances.

If you aren’t sure whether symptoms represent an emergency and the headache is severe, sudden, or accompanied by neurological changes, it is safer to obtain prompt medical evaluation.

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How Does a Healthcare Provider Evaluate a Headache?

The medical history is one of the most important parts of headache evaluation.

A clinician may ask:

• When did the headache start?
• Did it begin suddenly or gradually?
• What were you doing when it started?
• Where is the pain?
• Is it pressure-like, stabbing, throbbing, or burning?
• How severe is it?
• Is this the first headache like this?
• Have your usual headaches changed?
• Are there visual symptoms?
• Is there weakness or numbness?
• Is there nausea or vomiting?
• Is there fever?
• Is there neck stiffness?
• Was there a recent injury?
• What medications are you taking?
• Are you taking anticoagulants?
• Are you pregnant or postpartum?
• Do you have cancer or immune-system problems?

The physical examination may include:

• Blood pressure and other vital signs
• Mental-status assessment
• Cranial nerve examination
• Strength testing
• Sensation
• Coordination
• Balance and gait when appropriate
• Eye examination
• Neck examination

Many uncomplicated primary headaches can be diagnosed clinically without imaging.

However, concerning findings may prompt additional testing.

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Do You Need a CT Scan for a Headache?

Not every headache requires a CT scan or MRI.

Unnecessary imaging can expose patients to cost and, in the case of CT, radiation. On the other hand, imaging becomes important when clinicians suspect intracranial bleeding, certain vascular disorders, mass lesions, trauma-related complications, or other secondary causes.

For a sudden severe headache concerning for subarachnoid hemorrhage, emergency clinicians may use noncontrast head CT as part of the diagnostic evaluation. Depending on the timing, clinical findings, and residual level of concern after imaging, additional testing may sometimes be necessary.⁴

The appropriate imaging strategy depends on the clinical scenario.

This is why a clinician does not decide whether a headache is dangerous based solely on the pain score.

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How Are Common Headaches Treated?

Treatment depends on the cause.

For an uncomplicated primary headache, supportive measures can include:

• Rest
• Adequate hydration
• Regular meals
• Adequate sleep
• Reducing known triggers
• A quiet, dark room during migraine
• Appropriate over-the-counter medication when safe

Medications such as acetaminophen, ibuprofen, or aspirin may help some uncomplicated headaches.¹˒³

However, these medications are not appropriate for everyone.

NSAIDs such as ibuprofen may require caution or avoidance in people with certain kidney conditions, gastrointestinal bleeding or ulcer history, anticoagulant use, allergies, pregnancy considerations, or medication interactions.

Aspirin also has important age- and condition-specific precautions.

Always follow the product label or instructions from your healthcare professional.

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How Is Migraine Treated?

Migraine treatment can be divided into acute treatment, which attempts to stop or reduce an attack, and preventive treatment, which reduces future attacks.

Depending on the individual, treatment options may include:

• OTC analgesics
• Triptans
• CGRP-targeting medications
• Anti-nausea medications
• Preventive medications
• Lifestyle and trigger management

NINDS also recommends identifying personal triggers and maintaining consistent habits involving hydration, meals, sleep, and physical activity when appropriate.³

People with frequent, disabling, or poorly controlled migraine attacks should discuss preventive treatment with a healthcare professional.

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Can Taking Too Much Headache Medicine Make Headaches Worse?

Yes.

Frequent use of acute headache medications can contribute to medication-overuse or rebound headaches in susceptible individuals.

This can create a frustrating cycle:

Headache → medication → temporary relief → headache returns → more medication.

If you find yourself repeatedly taking headache medicine several days each week, discuss the pattern with your healthcare provider rather than simply continuing to increase the frequency or dose.

MedlinePlus specifically recommends medical follow-up when headache medications are being required frequently.¹

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What Can You Do at Home for a Mild Headache?

If the headache resembles a familiar, uncomplicated headache and there are no concerning symptoms, reasonable measures may include:

1. Resting in a comfortable environment.
2. Drinking fluids if you may be mildly dehydrated.
3. Eating if you have skipped meals.
4. Reducing bright light and noise, especially during migraine.
5. Getting adequate sleep.
6. Using an appropriate OTC pain medication if it is safe for you.
7. Monitoring for new or worsening symptoms.

Avoid repeatedly increasing medication doses beyond labeled instructions.

If your headache persists, becomes more frequent, changes significantly, or develops concerning features, seek medical evaluation.

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Frequently Asked Questions About Headaches

How do I know if my headache is serious?

A sudden severe headache or a headache accompanied by weakness, speech difficulty, confusion, loss of consciousness, high fever with neck stiffness, significant visual changes, or major head trauma requires prompt medical attention.²

A substantial change from your normal headache pattern also deserves evaluation.

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Is a headache on one side dangerous?

Not necessarily.

Migraine commonly causes one-sided head pain.³ Other primary headache disorders can also be unilateral.

The location alone does not determine whether a headache is dangerous. Sudden onset, neurological abnormalities, systemic symptoms, trauma, and other warning signs are more important.

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Is a headache behind my right eye a migraine?

It can be, but pain behind one eye has several possible causes.

Migraine, cluster headache, sinus-related conditions, and eye disorders can all cause pain in or around one eye.

Severe eye pain accompanied by redness or visual changes should receive prompt medical evaluation.

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Why do I keep getting headaches every day?

Frequent headaches can occur with migraine, tension-type headache, sleep problems, medication overuse, caffeine-related issues, musculoskeletal problems, and numerous other conditions.

Recurring headaches should be discussed with a healthcare professional, especially if they are new or increasing in frequency.

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Is a sudden headache always an aneurysm?

No.

There are multiple causes of sudden headache. However, subarachnoid hemorrhage from a ruptured aneurysm is one important diagnosis that clinicians must consider with a sudden severe headache, which is why thunderclap headache warrants emergency evaluation.⁴

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Can stress cause headaches?

Yes.

Stress can contribute to tension-type headaches and can also act as a migraine trigger in susceptible individuals.¹˒³

However, don’t automatically attribute a new severe or unusual headache to stress without considering other symptoms.

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Can lack of sleep cause headaches?

Inadequate or disrupted sleep can contribute to headaches and can trigger migraine attacks in some people.³

Maintaining a consistent sleep schedule may help some patients with recurrent headaches.

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Can skipping meals cause headaches?

Yes. Missed meals can contribute to headache and can trigger migraine attacks in some individuals.³

Regular meals and adequate hydration may help reduce headaches in people who identify these as triggers.

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When should I worry about a headache with dizziness?

Dizziness can accompany migraine and many benign conditions, but headache with sudden severe dizziness, inability to walk normally, weakness, speech problems, significant visual changes, or loss of coordination requires urgent evaluation (also see dizziness and when to worry).

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The Bottom Line: When Should You Worry About a Headache?

Most headaches are caused by conditions that are uncomfortable but not life-threatening.

Tension-type headaches often cause dull or squeezing pressure. Migraine commonly causes recurring moderate-to-severe headaches with symptoms such as nausea and sensitivity to light or sound.¹˒³

What matters most is recognizing when a headache doesn’t fit a reassuring pattern.

Seek emergency medical attention for a **sudden explosive headache, the worst headache you’ve experienced, or headache accompanied by new weakness, difficulty speaking, confusion, loss of consciousness, seizure, major visual changes, high fever with neck stiffness, or concerning symptoms after head trauma.**²˒⁵

For persistent or recurring headaches without emergency features, urgent care or primary care can help identify the type of headache, assess potential triggers, determine whether additional testing is needed, and develop an appropriate treatment plan.

When in doubt, pay attention not only to how much your head hurts, but also to how the headache began, whether it is different from your normal headaches, and what other symptoms are occurring with it.

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Medical References

1. MedlinePlus, U.S. National Library of Medicine. Headache.
Supports information regarding common headache patterns, tension-type headache, migraine features, evaluation and treatment.
MedlinePlus — Headache

2. MedlinePlus, U.S. National Library of Medicine. Headaches — Danger Signs.
Supports emergency warning signs including sudden explosive headache, neurological deficits, fever with neck stiffness, severe unilateral eye symptoms and significant changes in headache pattern.
MedlinePlus — Headache Danger Signs

3. National Institute of Neurological Disorders and Stroke (NINDS). Migraine.
Supports migraine symptoms, aura, triggers, headache diaries, acute treatments, preventive treatment and lifestyle approaches.
NINDS — Migraine

4. American College of Emergency Physicians (ACEP). Clinical Policy: Critical Issues in the Evaluation and Management of Adult Patients Presenting to the Emergency Department With Acute Headache.
Supports emergency evaluation of acute headache, including risk assessment and diagnostic approaches for suspected subarachnoid hemorrhage.
ACEP — Acute Headache Clinical Policy

5. MedlinePlus, U.S. National Library of Medicine. Head Injuries.
Supports warning signs following head trauma, including worsening headache, repeated vomiting, seizures, difficulty awakening, neurological deficits and increasing confusion.
MedlinePlus — Head Injuries