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Fever

Dr Lynn Thomas, OStJ, BSc, MB.BS, MA, FRCPClinically reviewed: 28/04/2025

A sustained high temperature above 38°C is called a fever. Find out what to look for and how to perform first aid.

What is a fever?

A fever is when a person has a persistent high temperature above 38°C (100.4°F). This is normally caused by a bacterial or viral infection and is often associated with a sore throat, earache, measles, meningitis, or chickenpox. Beware of recent overseas travel. If a young child’s temperature rises above 39°C (102. 2°F), this can be dangerous and might trigger a seizure.

Signs and symptoms

Look for:

  • a persistently high temperature - above 38°C.

  • feeling cold, with goose pimples, shivering, and chattering teeth.

Later they may have:

  • hot, flushed skin, and sweating

  • a headache

  • general aches and pains.

What to do

  1. 1

    If someone has a fever, help make them comfortable and keep them cool, ideally in bed with a sheet or light duvet.

    • Do not use a sponge to cool them as there is a risk of overcooling.

  2. 2

    Give the casualty plenty of cool drinks to replace any fluid loss through sweating.

  3. 3

    If they’re feeling unwell, you can give them the recommended dose of paracetamol for an adult, or the recommended dose of paracetamol syrup for a child.

    • Do not give aspirin to anyone under the age of 16.

  4. 4

    Monitor their level of response until they recover.

    • If you are worried, seek medical advice.

    In a child, contact 111 or the GP surgery if:

    • they are under 3 months and have a temperature over 38°C

    • they are 3-6 months and have a temperature over 39°C

    • the temperature has lasted for over five days

    • they do not want to eat or drink

    • they are dehydrated - nappies that are not very wet, they have sunken eyes

    • you are worried about them.

    In a child, call 999 or 112 if they:

    • have a stiff neck

    • have a rash that does not fade when you press it with a glass

    • are bothered by light

    • have a fit (febrile convulsion) for the first time.

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