Sudden Severe Headache – Causes

What To Do in a Severe Headache?

If you have a newly appearing severe headache, visit your doctor as soon as possible. Severe headache, or a headache that worsens with time, can be a symptom of a life threatening disorder, like bleeding within the head or intoxication.

What Can Cause a Severe Headache?

SUDDEN, UNEXPECTED severe headache can be caused by:

  • Insect-borne infections, like Dengue fever, malaria (in US in travelers returning from Africa), African sleeping sickness (trypanosomiasis), epidemic (Europena, classic) typhus, endemic typhus (in US: Texas, Califormnia – contact with rats, small mammals), Indian tick fever (in India, Mediteraneum), poliomyelitis (in small children in Afghanistan, India, Nigeria, Pakistan). Infections are transmitted by insects. Symptoms may include:
    • Severe headache
    • Fever
    • Vomiting
    • Fatigue
    • Rash
  • Q fever, transmitted from cattle, goats and sheep; worldwide. Symptoms may last for 2-3 weeks and may include:
    • Sudden severe headache
    • High fever
    • Muscle pains
    • Sore throat
  • Meningitis or encephalitis (bacterial, viral, fungal, chemical), as a complication of an infection of lungs or other organ, acquired as a droplet infection from another person, transmitted by a tick bite, or after a procedure, like myelography . Symptoms include:
    • Severe headache, usually starting in the back of the head, aggravated by bending the neck forward; neck stifness
    • High fever
    • Nausea and/or vomiting
    • Sensitivity to light (photophobia)
    • Back pain and pain in the legs
    • Unconsciousness (in severe cases)
  • Lyme disease (borelliosis), when an initial red “bull’s-eye” rash after a tick bite is overlooked and the infection is not treated, can cause symptoms several weeks or even years later:
    • Sudden severe headache and siff neck
    • Arthrittis, common in the knees
    • Muscle weakness, numbness
    • Paralysis of facial muscles
    • Heart problems resulting in palpitations, dizziness
    • Poor concentration and memory
    • Visual problems
  • Glaucoma, an increased pressure within the eye, triggered by stress, antihistamine medications, infection, injury or surgery. Symptoms include:
    • Sudden severe pain over one or both eyes
    • Blurred vision
    • Eye reddness
    • Nausea
  • Stroke causes headache only sometimes. Severity of a headache does not correlate with severity of stroke (1). Symptoms, usually on one side of the head or body, include:
    • Muscle weakness or paralysis
    • Loss of sensation
    • One-sided headache
    • Unconsciousness (rarely)
  • Ruptured brain artery aneurysm, resulting in bleeding between the brain and “arachnoid” membrane covering the brain (subarachnoid hemorrhage). Symptoms:
    • Severe ‘thunderclap’ headache
    • Nausea and/or vomiting
    • Neck stiffness and back pain (develops within hours)
    • Loss of consciousness (sometimes), (2).
  • Idiopathic intracranial hypertension (idiopathic means the cause is not known; CT or MRI of the head do not reveal any abnormalities) usually occurs in young obese women. Symptoms (3,4):
    • Recurrent, throbbing, severe headache lasting for hours
    • Blurred vision
    • Pain behind the eye
    • Noises in the ear (tinnitus)
    • Nausea
  • Primary thunderclap headache – sudden severe headache without a known cause.

SUDDEN severe headache with a SUSPECTED cause

  • Sinusitis (viral, bacterial, fungal, allergic) can cause:
    • Severe, pressure-like headache and tenderness in cheeks or forehead, aggravated by bending forward or lying down
    • Pain in the teeth or back of the head (sometimes)
    • Blocked nose, thick or clear nasal discharge
    • Sore throat and mild fever may be present.
    • There is usually no nausea or sensitivity to light
  • Hangover on the day after excessive alcohol drinking, usually includes:
    • Intense, throbbing headache
    • Tiredness
    • Nausea, loss of appetite
    • Sensitivity to light
    • Dizziness..
  • Food poisoning (staph, salmonella…) can trigger symptoms from 20 minutes to 72 hours after eating:
    • Vomiting and/or diarrhea
    • Abdominal cramps
    • Severe headache
    • Itch, reversal of hot/cold sensations, numbness, muscle paralysis or confusion can appear in seafood poisoning due to ciguatera toxin (in big tropical fish, like barracuda, mackerel), clupeotoxin (in anchovies, sardines, herrings, bonefish), scombroid poisoning (after eating non-properly preserved fish of any kind), and shellfish
  • Water-borne infections, like leptospirosis. Symptoms appear 2 days to 4 weeks after drinking water contaminated with animal urine and may last from few days to 3 weeks or longer:
    • Severe headache
    • High fever
    • Muscle aches
    • Red eyes, jaundice
  • Illegal drugs (cocaine, heroin, ecstasy, speed – amphetamines) abuse or withdrawal can cause:
    • Confusion
    • Nausea
    • Shallow breathing
    • Constricted pupils (in heroine), or dilated pupils (in cocaine, amphetamine)
    • Severe headache, which may be a symptom of bleeding within a head (intracranial hemorrhage), so it should be checked by a doctor as soon as possible
  • Poisons in the workplace and environment:
    • Carbon monoxide (CO) produced by cars (accidents or suicide attempts in garages), stoves, gas or propane powered engines (like pressure washers), in metal industry, mines, boilers, burners, grain silos or fermentation tanks can cause poisoning with the following symptoms:
      • Severe headache
      • Nausea
      • Fatigue
      • Chest pain
      • Bright pink or flushed red skin
      • Confusion
    • Poisonous plants, like foxglove, Lilly of The Valley, poisonous mushrooms can cause:
      • Vomiting, diarrhea, abdominal cramps
      • Hallucinations
      • Svere hedache
      • Unconsciousness (in severe cases)
      • Death (rarely)
  • Medications side effects, overdose or withdrawal
    • Nitroglycerin sublingual tablet or ointment
    • Opiates (morphine, codeine) overdose
    • Salicilates (aspirin) overdose
    • Vitamin A (intravenous) overdose..can cause:
      • Rebound headache – severe headache not responding to any analgetic
  • Hypoglycemia, common in diabetics, may cause
    • Severe headache in the morning
    • Weakness
    • Blurred vision
    • Unconsciousness
  • Blunt head injury with a skull fracture resulting in a collection of the blood above or below the brain membrane, called ‘dura’ (epidural or subdural hematoma). Another, often missed condition, causing headache is venous sinus thrombosis. Symptoms may include:
    • Sudden severe headache few hours or several days after an injury
    • Nausea and/or vomiting
    • Unconsciousness – may be transitional and occurs only sometimes
    • Limb weakness or unusual sensations on one side
  • Lumbar puncture may cause:
    • Severe pressure-like or throbbing headache few to 48 hours after the procedure and lasting for few days
    • Neck stiffness
    • Nausea
    • Sensitivity to light
  • High blood pressure can rarely cause a severe headache. Causes: adrenal tumor (pheochromocytoma). Symptoms:
    • Sudden throbbing headache on both sides or in the back of the head
  • Dissection of the vertebral artery, mostly occurring in sport injuries in young men, can cause:
    • ‘Thunderclap’ headache and unusual sensations in the back of the head
    • Problems with speech and other neurological symptoms
  • Brain abscess is a localized collection of pus in the brain, resulting from a spread of infection from another organ (like facial skin infection or pneumonia), mostly in patients with weakened immune system (corticosteroids, HIV/AIDS, diabetes, liver cirrhosis, chemotherapy), or congenital heart disease. Brain abscess can also result from a penetrating head injury. Symptoms:
    • Severe headache, stiff neck, confusion, fever
  • High altitude (mountain) sickness due to brain swelling. Symptoms appear within 6 hours to 4 days after arriving at high altitude:
    • Sudden, intense, throbbing frontal or diffuse headache
    • Shortness of breath
    • Weakness
    • Confusion, inability to sleep
    • Swelling of the face, hands and feet
  • Eclampsia are seizures appearing in late pregnancy, during delivery or few days thereafter. Symptoms and signs:
    • Seizures
    • Severe throbbing headache
    • Vision disturbance
    • Upper abdominal pain
    • Body swelling
    • High blood pressure (sometimes)


  • Migraine,triggered by monosodium glutamate (MSG), red wine, old cheese, strong scents… Symptoms:
    • One-sided, throbbing headache, aggravated by physical exertion, lasting 6-72 hours
    • Nausea or vomiting
    • Sensitivity to light
    • Aura – flashing lights or other unusual sensations preceding headache (only sometimes)
  • Hypercapnia – increased level of CO2 in the blood, due to chronic obstrucive pulmonary disease (COPD – bronchitis or emphysema), sleep apnea, miastenia gravis, resulting in:
    • recurrent severe both-sided headache, shortness of breath, sleepiness or delirium
  • Basilar artery migraine, mostly in young women during menstruation. Symptoms may include:
    • Strange sensations (aura), followed by one or both-sided pain on the back of the head
    • Partial or complete loss of vision
    • Poor muscle coordination
    • Slurred speech
    • Hearing problems
    • Dizziness
  • Cluster headache
    • Sudden, severe, one-sided headache, lasting for several minutes, repeating one or more times a day, several days in a row
  • Occipital neuralgia
    • Shooting pain and tenderness in the back of the head, usually due to a spinal disorder
  • Trigeminal neuralgia
    • Shooting, electro-shock-like facial pain triggered by touching the face, brushing the teeth…
  • MELAS (Mitochondrial myopathy, Encephalopathy, Lactic Acidosis, Stroke-like episodes) is a genetic disease, with onset of symptoms between 2-10 years of age:
    • Muscle weakness
    • Seizures
    • Attacks of severe throbbing headache in the back of the head lasting for few days
    • Various developmental disorders

Related Articles:


  1. Subarachnoid hemorrhage and severe headache (
  2. Stroke severity does not correlate with a headache severity (
  3. Idiopathic intracranial hypertension (pseudotumor cerebri) and severe headache  (
  4. Idiopathic intracranial hypertension, sleep apnea, obesity and headache  (
About Jan Modric (249 Articles)
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  • Aprons

    Yesterday my brother felt a sudden headache, fever and he vomited too much. Actually before he got that headache he was well and doing his assignment from school. Then after five minutes he cried for he told us that he is not feeling well. He then was so hot and vomited. My brother is only 13 years old and I wonder what causes his sudden headache. So I look upon the net and I stumbled upon here. Still I need guidance and specific illness. I’m really anxious for my brother.

    • Jan Modric


      take your brother to the doctor immediately and do not search for answers on the internet. He could have meningitis or some other life-threatening condition.

  • Theresa Cliffords

    I developed severe headache and lower back pain after a 2 day period what could be the problem even in my previous period it lasted 2 day I also developed severe headache too but no back ache

    • Hi Theresa. Sometimes the menstrual-related headaches are linked to the changes in hormone levels. It can occur even if you never had this problem in the past. It is more likely to occur in women who suffer with PMS. In your case you are reporting a headache after your period and while this may also be related to hormones, it is also to consider conditions like iron-deficiency anemia. However, it is also important to note that while lower backache is not uncommon during your periods, unusual pain could be originating from th uterus, fallopian tubes or ovaries and may in fact be a symptom of endometriosis or PCOS although you would have noted some menstrual abnormalities as well. It is advisable that you consult with your gynecologist.

  • Please help

    Please help! i’m miserable. I’m tired of going to the dr because i’m afraid they think i’m looking for something wrong with me. I’ve been dizzy for 3 weeks. i’m had a constant headache on both sides of my head and it feels really heavy. i’ve tried meclazine but it hasn’t done anything and tried imitrex and nothing! I’m been on prednisone and augmentin but that hasn’t helped either. I have had the sinus surgery in 04 and these headaches do not feel like sinuses. I’ve been to the ER for shortness of breath along with these problems. My blood gas has been fine, and my blood work came back normal. The past few days i’ve experienced tingling in the face and my right hand feels heavy. My dr gave me the imitrex yesterday but all it did was cause stomach issue. (like tightening and pain like an ulcer) Any help i would appreciate.

    • Hi. You have not mentioned your age, gender or other medical history so the advice is going to be broad and rather general. Firstly, you should consult with a neurologist if you are not already doing so. Secondly, the concern here is whether this is related to any disruption in the blood flow to the brain. If you are over 40 years, a smoker, overweight/obese or if you have a family history of strokes then this would have been considered. Of course, most of these symptoms could be due to conditions like migraines, vertigo and certain inner ear diseases. Seeing that you have tried so many drugs with no relief you should be looking at consulting with a neurologist or seeking a second opinion from another doctor.

    • holly

      I seem to have the same problem for the past 7 weeks. My MRI showed pronounced enhancement of cranial nerve 7. My primary nd believes this is causing inflammation which effects cranial nerve8, exhibiting senorimotor symptoms. He believes I have vestibular neuroritis caused by a viral infection but refuses to prescribe an antiviral medication. I’m at wits end and feel your pain!