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Severe Headache: Possible Causes & When to See a Doctor

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Last updated January 19, 2021

Severe headache questionnaire

Use our free symptom checker to find out what's causing your ache.

Severe headaches can be caused by headache syndromes, medication overuse, underlying medical conditions, decreased/increased pressure and arterial problems.

Severe headache questionnaire

Use our free symptom checker to find out what's causing your ache.

Severe headache symptom checker

Symptoms of a severe headache

Most people get mild headaches from time to time. However, some conditions cause recurring headaches so severe that it is impossible to continue normal daily activities. In other cases, a new type of severe headache can arise suddenly. Depending on the cause, the headache can be located in different parts of the head, can last for a short or long amount of time, and may be throbbing, non-throbbing, intermittent, continuous, dull or sharp in quality.

Severe headaches can occur due to an identifiable cause such as an injury. They can also happen without an underlying medical problem. In this case headaches are thought to occur due to overexcitement of nerve endings in the brain.

Common accompanying symptoms of a severe headache

If you're experiencing a severe headache, you may also experience:

Severe headache causes

Headache syndromes

In some cases, severe headaches have characteristic features that allow for the diagnosis of a specific chronic headache syndrome.

Medication overuse

Unfortunately, overuse of pain medications to treat your headaches can actually make them worse over time. The headaches may increase in frequency until they occur every day.

Underlying medical conditions

Many medical conditions can cause headaches that may be severe. For example, an eye condition called glaucoma can trigger an acute and severe headache. Extremely high blood pressure can also cause a headache.

Decreased pressure

Loss of some of the fluid that surrounds the brain and spinal cord can decrease pressure in the skull and lead to headaches. This is a common complication following a lumbar puncture or after epidural anesthesia used during certain operations or childbirth with vaginal deliveries.

Increased pressure

Increased pressure within the skull due to a process within or surrounding the brain will commonly lead to a severe headache along with other symptoms, such as vomiting or confusion.

  • Structural causes: A structural abnormality in the brain, such as a tumor or a malformation that has been present since birth, can cause increased pressure.
  • Infection: An infection of the fluid surrounding the brain (meningitis) or of the brain itself (encephalitis) can cause severe headache symptoms.
  • Bleeding: Head trauma, rupture of an abnormally shaped blood vessel (subarachnoid hemorrhage due to ruptured brain aneurysm), or extremely high blood pressure can cause bleeding in the brain, resulting in increased pressure and a headache.

Arterial problems

Arterial problems that can result in severe headaches include the following.

  • Injury: An injury to the carotid artery, one of the major arteries in the neck, can cause a severe headache on the side of the injury. This may also result in a stroke.
  • Inflammation: The artery passing over your temple can become inflamed, causing severe headache in that area.
  • Blockage: A clot or other type of blockage of an artery in the brain can cause a sudden and severe headache.

New migraine

New, or new-onset, migraine means the person has never experienced a migraine headache before. A migraine is a one-sided headache that causes intense pain and throbbing due to blood vessels dilating in the brain.

The exact reason for new-onset migraine headache is not known, but a number of causes are being studied:

  • Pregnancy.
  • Soy isoflavone supplements, especially in men.
  • Use and overuse of certain medications.
  • Traumatic head injury.
  • Angioma, which is a cluster of dilated blood vessels in the brain.
  • A complication of surgery for some heart conditions.

Anyone with a sudden severe headache should be seen by a medical provider, so that a more serious cause can be ruled out. A transient ischemic attack, also known as TIA or mini-stroke, can have symptoms similar to a migraine but is far more serious.

Diagnosis is made through patient history, physical examination, and imaging such as a CT scan.

Treatment for migraine varies with the individual. Lifestyle changes may be recommended and there are a number of medications that may be tried.

Rarity: Common

Top Symptoms: new headache, fatigue, nausea, mild headache, headache that worsens when head moves

Symptoms that always occur with new migraine: new headache

Symptoms that never occur with new migraine: fever, diarrhea, productive cough, headache resulting from a head injury

Urgency: Self-treatment

Severe headache questionnaire

Use our free symptom checker to find out what's causing your ache.

Severe headache symptom checker

Tension headache (first onset)

Tension-type headaches are the most common type of headache. It is pain or discomfort in the head and/or neck. It's often associated with muscle tightness in these areas. This condition can occur as little as once a year (infrequent) but as often as more than 15 days per month (chronic). The cause of tension-type headaches is not clear.

Rarity: Common

Top Symptoms: new headache, nausea or vomiting, moderate headache, loss of appetite, mild headache

Symptoms that always occur with tension headache (first onset): new headache

Symptoms that never occur with tension headache (first onset): photo and phonophobia, throbbing headache, headache resulting from a head injury

Urgency: Self-treatment

Cluster headache

A cluster headache is a type of recurring headache that is moderate to severe in intensity. It is often one-sided head pain that may involve tearing of the eyes and a stuffy nose. Attacks can occur regularly for 1 week and up to 1 year. Each period of attacks (i.e. each cluster) is separated by pain-free periods that last at least 1 month or longer. Other common headaches may also occur during these cluster-free periods.

Rarity: Uncommon

Top Symptoms: severe headache, nausea, throbbing headache, history of headaches, sensitivity to light

Symptoms that always occur with cluster headache: severe headache

Urgency: Hospital emergency room

Insomnia disorder

Insomnia disorder is a short-term or chronic condition whereby individuals have difficulty sleeping. Other common symptoms include fatigue, difficulty with concentration, social dysfunction, reduced motivation, and behavioral changes. The short-term form of the condition is usually ...

Common cold

The common cold is a viral infection of the upper respiratory tract, which includes the nose, mouth, sinuses, throat, and larynx. There are over 200 viruses that can cause upper respiratory infections, and usually the exact virus behind a cold is never known.

The common cold is, of course, very common..

Acute bacterial sinusitis

Acute bacterial sinusitis, also called bacterial rhinosinusitis or "sinus infection," has symptoms much like viral rhinosinusitis but a different treatment.

Any sinusitis usually begins with common cold viruses. Sometimes a secondary bacterial infection takes hold. Like cold viruses, these bacteria can be inhaled after an infected person coughs or sneezes.

Anyone with viral sinusitis, upper-respiratory allergy, nasal passage abnormality, lung illness, or a weakened immune system is more prone to bacterial sinusitis.

Symptoms include thick yellowish or greenish nasal discharge; one-sided pain in the upper jaw or teeth; one-sided sinus pain and pressure; fatigue; fever; and symptoms that get worse after first improving.

See a doctor right away for severe headache, high fever, stiff neck, or vision changes. These can indicate a medical emergency.

Diagnosis is made with a simple examination in the doctor's office.

Bacterial sinusitis can be treated with antibiotics, but this is not always necessary. Often rest, fluids, and over-the-counter pain relievers and decongestants are enough.

Prevention is done through good lifestyle and hygiene to keep the immune system strong.

Rarity: Common

Top Symptoms: fatigue, headache, cough, sinusitis symptoms, muscle aches

Symptoms that always occur with acute bacterial sinusitis: sinusitis symptoms

Symptoms that never occur with acute bacterial sinusitis: clear runny nose, being severely ill

Urgency: Primary care doctor

Sinus headache

Sinus headache, also called sinusitis or rhinosinusitis, is caused by either a bacterial or a viral infection of the sinuses (open spaces) behind the eyes and nose.

Symptoms include fever; thick nasal discharge which may be clear, white, greenish or yellowish; some loss of sense of smell; foul-smelling breath; and pain, congestion, and pressure over the sinus areas of the face, especially if bending forward or lying down.

A self-diagnosed "sinus headache" very often turns out to be a migraine headache with a few sinus symptoms. This requires very different treatment from an actual sinus headache, and is an important reason to see a medical provider about any sort of ongoing headaches.

Diagnosis is made through patient history, physical examination, and sometimes CT scan or MRI of the head to look for changes in the sinuses.

A true sinus headache, if caused by a bacterial infection, will be treated with antibiotics. If caused by a viral infection, the symptoms can be treated with over-the-counter pain relievers and alternating hot and cold compresses.

Rarity: Common

Top Symptoms: headache, headache that worsens when head moves, facial fullness or pressure, mucous dripping in the back of the throat, sinus pain

Symptoms that always occur with sinus headache: headache

Symptoms that never occur with sinus headache: fever, being severely ill, sore throat, muscle aches, cough, drooping eyelid, wateriness in both eyes

Urgency: Self-treatment

Cluster headache (first attack)

A "new onset" cluster headache means that the person has never experienced a cluster headache before. These headaches most commonly start after age 20.

A cluster headache is characterized by intense pain on one side of the forehead, especially over one eye. It often strikes in "clusters," meaning the headache comes and goes frequently. It may occur at about the same time of day for several days or weeks in a row.

The specific cause for cluster headache is not known. Drinking alcohol, breathing strong fumes, exercising to the point of becoming overheated, and heavy smoking are all possible triggers.

Diagnosis is made through patient history, since there is no specific test for cluster headache. Blood tests, neurologic tests, and imaging such as a CT scan or MRI may be done to rule out any other cause for the new onset of head pain.

Referral will be made to a headache specialist, who can offer new treatments to help the patient manage the symptoms and improve quality of life.

Rarity: Uncommon

Top Symptoms: new headache, severe headache, nausea, throbbing headache, congestion

Symptoms that always occur with cluster headache (first attack): severe headache, new headache

Urgency: Hospital emergency room

Thunderclap headache

A severe headache that's the worst of one's life could be the sign of a bleed in the brain. You should see a doctor immediately!

Rarity: Uncommon

Top Symptoms: thunderclap headache

Urgency: Hospital emergency room

Concussion not needing imaging

A traumatic brain injury (TBI), or concussion, happens when a bump, blow, jolt, or other head injury causes damage to the brain. Every year, millions of people in the U.S. suffer brain injuries. More than half are bad enough that people must go to the hospital, and the worst injuries can lead to permanent brain damage or death.

Rarity: Common

Top Symptoms: dizziness, irritability, depressed mood, difficulty concentrating, trouble sleeping

Symptoms that always occur with concussion not needing imaging: head or face injury

Symptoms that never occur with concussion not needing imaging: recent fall from 6 feet or higher, severe vomiting, posttraumatic amnesia over 30 minutes, slurred speech, fainting, moderate vomiting

Urgency: Primary care doctor

Severe headache treatments and relief

A severe headache may be a sign of a dangerous injury or medical condition and will often require urgent evaluation.

Seek emergency severe headache treatment for the following

You need to seek emergency care if:

  • You have a sudden and extremely severe headache: Even if it is followed by gradual improvement.
  • You have never had a headache as severe as the one you are experiencing now
  • You have neck stiffness and/or fever
  • You are experiencing neurological changes: Such as unequal pupils, confusion, facial weakness on one side, or changes in vision
  • The headache started after a head trauma or intense exercise

In some cases, even though emergency treatment isn't necessary, you may need medical evaluation and treatment.

Severe headache questionnaire

Use our free symptom checker to find out what's causing your ache.

Severe headache symptom checker

When to see a doctor for severe headaches

Make an appointment with your medical provider if:

  • Your headaches are becoming more severe or more frequent
  • Your headaches are accompanied by certain signs that are typical of headache syndromes: Such as visual changes like spots or lines, nausea, inability to tolerate light and sound, and a runny nose or eye tearing on the same side as the headache
  • You have tenderness over your temple
  • Your headaches are severe enough to interfere with your daily life
  • You recently had a lumbar puncture or epidural anesthesia

Medical treatments for severe headaches

Your medical provider may prescribe one of the following severe headache treatments, depending on the cause of your severe headache:

  • A daily medication to prevent future headaches: And/or a medication to take to stop a headache once it has begun.
  • Referral to a neurosurgeon: If your headaches are being caused by a structural abnormality
  • Treatment for any underlying medical conditions that may be contributing to the headache
  • Using a headache calendar: This can help track your headaches, identify triggers, and monitor your response to treatment.
  • Stopping a pain medication that may be contributing to the headache

At-home treatments and prevention

Some home treatments may help with severe headache symptoms

  • Avoid strong smells, cigarettes, and caffeine
  • Use good sleep hygiene: Such as going to sleep at the same time every night and avoiding electronics at bedtime
  • Avoiding stressful situations and using stress reduction techniques: Meditation can help prevent headaches.

FAQs about severe headache

Can lack of sleep cause a severe headache?

Yes, it is possible for lack of sleep to cause a severe headache. Obstructive sleep apnea, a medical condition that causes decreased sleep quality, can cause headaches. In addition, lack of sleep can trigger headaches if you have a chronic headache syndrome such as migraines.

Why do I have a constant severe headache?

Unfortunately, a constant severe headache can develop when a headache syndrome progresses over time. This often occurs due to overuse of pain medications to treat the original headaches, and may improve if you stop taking the medications. A constant severe headache can also arise without a history of headache, as in the case of the headache syndrome called new daily persistent headache.

Why is my headache only on the right side of my head?

Many headache syndromes, such as migraines and cluster headaches, typically cause pain on only one side of the head. Inflammation of the temporal artery or injury to the carotid artery can cause a headache only on the side of the injury [6,7].

Why does my head pain increase when I cough?

For some people, coughing can trigger a headache or worsen a pre-existing headache. This is thought to occur because coughing briefly increases pressure within the skull. Similar processes like straining to go to the bathroom or exercise can similarly contribute to head pain. Headache associated with coughing can occur on its own with no underlying cause, or it can be due to an underlying medical condition such as a structural malformation of the brain.

Can my severe headache cause blurred vision?

One type of severe headache, a migraine, can cause blurred vision or other changes such as lines or spots in your visual field. However, a headache with blurry vision can be a sign of something more serious, like stroke. If the blurry vision is different from what you usually experience with headaches, or if it lasts for more than an hour, you should seek emergency care.

Questions your doctor may ask about severe headache

  • Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
  • Any fever today or during the last week?
  • Have you experienced any nausea?
  • Have you lost your appetite recently?

Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.

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Dr. Rothschild has been a faculty member at Brigham and Women’s Hospital where he is an Associate Professor of Medicine at Harvard Medical School. He currently practices as a hospitalist at Newton Wellesley Hospital. In 1978, Dr. Rothschild received his MD at the Medical College of Wisconsin and trained in internal medicine followed by a fellowship in critical care medicine. He also received an MP...
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  2. Headache disorder. World Health Organization. Published April 8, 2016. WHO Link.
  3. Jasmin L. Headaches - danger signs. U.S. National Library of Medicine: MedlinePlus. Updated December 6, 2018. MedlinePlus Link.
  4. Facts about glaucoma. National Eye Institute. Updated September 2015. NEI Link.
  5. Increased intracranial pressure (ICP). Johns Hopkins Medicine. Johns Hopkins Medicine Link.
  6. Mirza Z, Hayward P, Hulbert D. Spontaneous carotid artery dissection presenting as migraine--a diagnosis not to be missed. J Accid Emerg Med. 1998;15(3):187-9. NCBI Link.
  7. Rigamonti A, Iurlaro S, Zelioli A, Agostoni E. Two symptomatic cases of cluster headache associated with internal carotid artery dissection. Neurol Sci. 2007;28 Suppl 2:S229-S231. NCBI Link.