A fever is a high temperature. As a general rule, a temperature of 38C (100.4F) or above is a fever.
As a parent it can be extremely worrying if your child has a high temperature. But it's very common and often clears up by itself.
A quick and easy way to find out whether your child has a fever is to take their temperature using a thermometer .
Most fevers are caused by infections or other illnesses. The high body temperature makes it more difficult for the bacteria and viruses that cause infections to survive.
Common conditions that can cause fevers include:
Your child's temperature can also be raised after vaccinations, or if they overheat because of too much bedding or clothing.
Contact your doctor or health visitor urgently if your child:
You should also see your doctor if your child has other signs of being unwell, such as persistent vomiting, refusal to feed, floppiness or drowsiness.
If it isn't possible to contact your doctor.
If your child seems to be otherwise well – for example, if they're playing and attentive – it's less likely they're seriously ill.
If your child has a fever, it's important to keep them hydrated by giving them plenty of cool water to drink.
Babies should be given plenty of liquids, such as breast milk or formula. Even if your child isn't thirsty, try to get them to drink little and often to keep their fluid levels up.
If the environment is warm, you could help to your child to stay at a comfortable temperature by covering them with a lightweight sheet or opening a window.
However, they should still be appropriately dressed for their surroundings and sponging your child with cool water is no longer recommended to reduce a fever.
Children's paracetamol and ibuprofen can help to reduce a fever, but they're not always needed. If your child doesn't seem distressed, there's no need to give them medicine to lower their temperature.
If your child is distressed, don't give them paracetamol and ibuprofen at the same time. Try one on its own first. If they're still distressed before the next dose is due, you could try the other medicine instead.
Call your doctor if you've tried both medicines and they haven't helped.
When giving your child a medicine, always read the packet or leaflet that comes with it to find out how much to give them and how often.
Read more about treating a high temperature in children.
Sometimes a high temperature in children is associated with more serious signs and symptoms, such as:
Possible serious bacterial illnesses include:
It's important to remember that potentially serious causes of fever are relatively rare.
Read more about recognising the signs of serious illness in babies and children .
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.