Causes of high temperature
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:
- upper respiratory tract infections (RTIs)
- ear infections
- roseola – a virus that causes a temperature and a rash
- kidney or urinary tract infections (UTIs)
- common childhood illnesses, such as chickenpox and whooping cough
Your child's temperature can also be raised after vaccinations, or if they overheat because of too much bedding or clothing.
When to get urgent medical advice
Contact your GP urgently, if your child:
- is under three months old and has a temperature of 38C (100.4F) or above
- is between three and six months old and has a temperature of 39C (102.2F) or above
You should also see your GP if your child has other signs of being unwell, such as:
- persistent vomiting
- refusal to feed
- floppiness or drowsiness
If your child seems to be otherwise well, for example, if they're playing and attentive, it’s less likely they're seriously ill.
How to assess if your child is unwell
It can be difficult to tell when a child is seriously ill, but the main thing is to trust your instincts.
It is unlikely there is any serious illness if your child is:
- a normal colour
- breathing normally
- smiling and responsive
Below are warning signs that might be serious.
If your child:
- appears pale, it can be a sign that the illness is becoming more serious, and you should seek advice
- is mottled, ashen, or blue; this requires urgent assessment and may be an emergency
If your child:
- is not responding normally, and needs much more encouragement than usual to respond, you should seek advice
- becomes unresponsive, appears unusually unable to stay awake, displays weak, high-pitched, or continuous crying; this requires urgent assessment and may be an emergency
If your child:
- appears to be breathing more rapidly (this depends on their age) then you should seek medical advice
- 6–12 months of age: more than 50 breaths per minute
- over 12 months of age: more than 40 breaths per minute
- is grunting or appears distressed breathing or is taking more than 60 breaths per minute; this requires urgent assessment and may be an emergency
- if symptoms or signs of dehydration are present you should seek advice
Treating a fever
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.
Other things that can help keep your child comfortable include:
- dressing your child in light clothing (appropriate for their surroundings)
- putting your child in a room with a comfortable temperature
- if they're warm, covering them with a lightweight sheet or opening a window
Sponging your child with cool water isn't recommended to reduce a fever.
You can't give them both at the same time. If one doesn't work, you may want to try the other later. You should allow at least three hours to see if the medicine is working before trying an alternative.
Antipyretics aren't always necessary. If your child isn't distressed by the fever or underlying illness, there's no need to use antipyretics to reduce a fever.
When using antipyretics, always read the patient information leaflet that comes with the medication to find the correct dose and frequency for your child's age.
More serious illnesses
Sometimes a high temperature in children is associated with more serious signs and symptoms, such as:
- fits or seizures
Possible serious bacterial illnesses include:
- meningitis – infection of the meninges, the protective membranes that surround the brain and spinal cord
- septicaemia – infection of the blood
- pneumonia – inflammation of the lung tissue, usually caused by an infection
It's important to remember that potentially serious causes of fever are relatively rare.