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Severe Headache: Possible Causes & When to See a Doctor

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

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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.

Thunderclap headache

A thunderclap headache is a severe headache that feels like the worst of one's life and it 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

Tension headache (first onset)

Tension headache is described as feeling like there is a band around the head that gets tighter and tighter. The headaches may occur in episodes – a few times a week – or chronically, where they almost never entirely go away.

This is a common type of headache but the cause remains unclear. It may be a combination of stress and an overactive sensitivity to pain.

Symptoms include dull, aching pain and tightness in the forehead, sides, and back of the head, and sometimes pain in the neck and shoulder muscles. Unlike migraines, there is usually no nausea, vomiting, or sensitivity to light.

Tension headaches are not dangerous in themselves, but can interfere with work and with quality of life.

Diagnosis is made through patient history and sometimes physical examination. CT scan or MRI may be done to rule out a more serious cause of the headaches.

Over-the-counter and other pain relievers are sometimes prescribed. Lifestyle changes to reduce stress, improve diet, and increase exercise are often helpful, as is massage and biofeedback.

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

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 , 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

New migraine

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

Insomnia disorder

Insomnia disorder means being unable to fall asleep, or to stay asleep long enough to get the normal seven to eight hours of sleep per night.

Common causes are pain; sleep apnea; depression; stress and worry over life events; circadian rhythm disorders such as jet lag; aging; and certain medications.

Many medical conditions, such as diabetes and heart disease, cause poor sleep. Women who are pregnant or menopausal may experience insomnia due to hormone shifts.

Symptoms include waking up during the night; feeling tired in the morning; daytime sleepiness and irritability; and increased errors and accidents through inability to concentrate.

Diagnosis is made through physical examination, patient history, and sometimes testing at a sleep study center.

Treatment consists of addressing underlying medical conditions, along with managing stress and checking all medications and supplements.

Improving "sleep hygiene" means establishing a routine of lying down in a dark room at the same time each night, with no television, computer, or phone. Avoiding food and caffeine before bedtime will prevent heartburn and wakefulness while trying to sleep.

Concussion not needing imaging

A concussion is also known as traumatic brain injury or TBI.

Concussion is the result of being struck in the head. In some cases, especially with infants, being violently shaken so that the head whips back and forth can also cause a concussion.

Most susceptible are those playing contact sports. However, concussion is often the result of an automobile accident or simple fall and can happen to anyone.

Symptoms include headache; loss of balance and coordination; difficulty with memory and concentration; and sometimes, but not always, loss of consciousness.

If symptoms do not clear within a few hours, or seem to get worse, take the patient to the emergency room or call 9-1-1.

Diagnosis is made through patient history and physical examination. A mild concussion does not show up on imaging because there is no bleeding or swelling in the brain. Mild concussion is entirely a disruption in brain function, with nothing to see on an image.

A concussion does not usually need treatment, but head injuries can result in more serious complications, like bleeding in the brain, you should be seen for an evaluation today, just to be sure. The health care provider will determine if imaging of your head, like a CT scan, is necessary. If your symptoms change or worsen, go to the ER immediately.

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

Common cold

The common cold is a contagious viral infection that can cause cough, congestion, runny nose, and sore throat. Most adults catch two to three colds per year, and kids can get more than eight colds each year.

Rest and drink plenty of fluids. Colds are contagious and can easily spread to other people, so if possible, avoid close contact with others, such as hugging, kissing, or shaking hands. Colds typically resolve within 7 to 10 days.

Cluster headache (first attack)

A "new onset" cluster headache means that the person has never experienced a 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

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

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

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.

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.
  • Pain Relievers: Medications like ibuprofen or acetaminophen can help relieve headache pain.

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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The stories shared below are not written by Buoy employees. Buoy does not endorse any of the information in these stories. Whenever you have questions or concerns about a medical condition, you should always contact your doctor or a healthcare provider.
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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  1. Allergy headaches. National Headache Foundation. National Headache Foundation Link.
  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.