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What to do if…
you have a sudden, severe, and unusual headache

Produced and maintained by PanicStation.org Published: Last reviewed: Editorial policy USA guide

Short answer

If you have a sudden, severe headache that is unusual for you, especially a “worst ever” or thunderclap headache, call 911 now and do not drive yourself.

Do not do these things

  • Do not sleep it off if it started suddenly, is extremely severe, or comes with new neurological symptoms.
  • Do not drive yourself to the ER if you feel faint, confused, very drowsy, weak, unsteady, or your vision is affected.
  • Do not exceed label doses of pain medicines.
  • Do not take more than one medicine containing acetaminophen at the same time unless a clinician has told you to.
  • Do not drink alcohol or take sedatives to dull symptoms.
  • Do not stay alone if symptoms are severe, sudden, or changing.

What to do now

  1. Reduce immediate risk. Sit or lie down somewhere safe. If possible, have someone stay with you and keep the door unlocked or accessible for emergency responders.
  2. Call 911 right away if any of these are present, even if symptoms improve:
    • The headache came on suddenly and became very severe within seconds or minutes.
    • It feels like the worst headache of your life or very different from your usual headaches.
    • Face drooping, arm or leg weakness or numbness, especially on one side, speech trouble, sudden vision problems, sudden severe dizziness, or trouble walking.
    • Confusion, fainting, seizure, collapse, or being very drowsy or hard to wake.
    • Severe headache after a significant head or neck injury.
    • Severe headache with fever and stiff neck, a new rash, or you look or feel seriously ill.
    • Severe headache with a painful red eye, sudden major vision change, blurred vision, or halos around lights.
    • Severe headache during pregnancy or within a year after giving birth, especially with vision changes, dizziness, fainting, swelling of the face or hands, chest pain, shortness of breath, or feeling that something is very wrong.
  3. If you are unsure, choose emergency evaluation. For a severe, sudden, unusual headache you cannot explain, go to the Emergency Department, and call 911 rather than driving if transport is not clearly safe.
  4. When you call 911 or arrive at the ER, say the key details plainly:
    • The exact start time and how quickly the pain peaked.
    • What you were doing when it started, including exertion, coughing, sex, or an injury.
    • Any weakness, numbness, speech trouble, vision change, dizziness, vomiting, fever, neck stiffness, confusion, fainting, seizure, or collapse.
    • Whether you are pregnant, recently gave birth, take blood thinners, have had a recent infection, or had a recent head or neck injury.
    • Your medicines, allergies, and important medical conditions.
  5. If you are pregnant or gave birth within the last year, say that clearly to 911, EMS, and ER staff. Do not delay calling 911 to check your blood pressure or look up symptoms.
  6. While waiting for help, keep your phone nearby, gather ID and medication information only if it is easy, and avoid alcohol, sedatives, and extra pain medicine unless a clinician tells you to take it.

What can wait

  • Searching online to work out what kind of headache it is.
  • Asking friends or family to decide whether it is serious enough.
  • Deciding which test you need.
  • Finishing work, chores, messages, or plans.
  • Worrying about the cost, paperwork, or what happens after the first medical check.

Important reassurance

Many headaches are not dangerous, but a sudden, severe, unusual headache is treated urgently because some causes are time-sensitive. Getting checked quickly is a protective choice, not an overreaction.

Scope note

These are first steps only, meant to help you stay safer and get urgent evaluation. Later decisions may need help from emergency clinicians, your usual doctor, a neurologist, an obstetric clinician, or another appropriate specialist.

Important note

This is general information, not medical advice, a diagnosis, or professional care. If you think you may be having an emergency, call 911.

Additional Resources

Closely connected guides that may be useful during the same situation or its immediate aftermath.

About this guide

This guide was produced and is maintained by PanicStation.org using its published editorial process. Official and specialist sources are checked where relevant, and AI-assisted tools may be used for drafting, organisation, and consistency checks. The site operator remains responsible for publication, revision, and removal decisions.

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