Fever
By the AllHealth UK editorial teamLast reviewed Next review due Compiled from published NHS and NICE guidance. Not reviewed by a clinician.
Key facts
A fever is a temporary rise in body temperature. The NHS considers 38°C or above to be a high temperature. It's usually a sign your body is fighting an infection and is rarely dangerous on its own in adults.
Most often affects:Children under 5Elderly adultsPeople with weakened immunity
What commonly causes fever
- Viral infections (cold, flu, COVID-19)
- Bacterial infections (UTI, strep throat)
- Inflammatory conditions
- Heat exhaustion or heatstroke
- Medication side effects
- Post-vaccination response
What helps at home
- Rest and drink plenty of clear fluids — water, diluted squash, or clear broth
- Take paracetamol or ibuprofen to reduce temperature and relieve discomfort
- Wear light, breathable clothing — avoid bundling up
- Do not sponge your child down or cool their skin with damp cloths — the NHS says a high temperature is a natural and healthy response to infection.
- You do not need to keep taking your temperature — how unwell you feel matters more than the number. If you feel hot, cold or shivery you may have a high temperature even if the thermometer reads under 38C.
- Keep the room at a comfortable temperature — not too hot
When to get help
These three levels are different. Getting the level right is the single most useful thing this page can do for you.
Non-urgent advice: see a GP if
- Your temperature has been above 38°C for more than 3 days
- The fever keeps returning over several weeks
- You have night sweats or have lost weight without trying
- You still feel unwell weeks after the temperature settled
Urgent advice: ask for an urgent GP appointment or call 111 if
- Your temperature is above 38°C and does not come down with paracetamol
- You have a fever and your immune system is weakened — for example by chemotherapy or steroid treatment
- You have a fever after returning from a country where malaria is found
Immediate action required: call 999 or go to A&E if
- A rash that does not fade when you press a glass against it
- Fever with confusion, drowsiness, or difficulty waking
- Fever with difficulty breathing or bluish lips
- Uncontrollable shivering, or skin that is pale, blotchy, blue or grey, or feels cold to the touch — these can be signs of sepsis
- A fever with a very painful headache, a stiff neck, or being unable to look at bright lights
What to do next
Not sure whether fever needs a doctor? These are your options, cheapest and fastest first.
Questions people ask about fever
Reducing the chance of it coming back
- Wash hands regularly with soap for at least 20 seconds
- Stay up to date with vaccinations (flu jab annually)
- Avoid close contact with people who are unwell
- Keep your immune system strong with good nutrition and sleep
Conditions this can be part of
Listed alphabetically, not by likelihood — this page does not tell you which one you have.
- COVID-19
- Ear infection
- Flu
- Urinary tract infection
Sources and further reading
This page was written from the following published guidance. All links checked 26 August 2026.
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