What is a fever?

Normal body temperature is about 36.4°C. A high body temperature is 38°C or more and is known as a fever. Illnesses like colds and flu, ear infections and tonsillitis, may cause fever in babies. Your baby’s body temperature rises when they have an infection because it’s more difficult for the germs that cause illness (bacteria and viruses) to survive in a high body temperature. 

If you think your baby has a fever, you can check for the following signs:

• Do they feel sweaty?
• Do they look or feel unwell? 
• Do their cheeks look flushed?
• When you touch their forehead, stomach or back, do they feel hot? 
• Does the thermometer show a body temperature of more than 38°C?

If you think your baby has a temperature, it’s best to check with a thermometer.

Checking your baby’s temperature with a thermometer

You can buy a thermometer at a pharmacy or supermarket. Digital thermometers are preferable because they are fast and accurate. To take your baby’s temperature, place the thermometer in their armpit. Hold their arm gently but firmly against their body for the length of time recommended on the thermometer’s instructions (usually about 15 seconds). 

Remember that a higher body temperature doesn’t always mean something’s wrong.
Babies’ temperatures can be affected by various things outside of their bodies. Wait for a few minutes for them to cool down without getting shivery or too cold before you take your baby’s temperature if:

• Your baby was wrapped in a warm blanket
• You just gave them a warm bath
• They were in a warm room or in the sun
• They have been very active
• They are wearing a lot of clothing

When should you see a doctor? *

A fever usually only lasts for 3 to 4 days in young children, but you should take your baby to see a doctor:

  • You think they have a high temperature or they have a temperature of 38C or above and are younger than 3 months old
  • Your baby is between 3 and 6 months old and has a temperature of 39C or more or you think they have a high temperature
  • Your baby has had a fever for 5 days or more
  • Your baby is refusing to eat or isn’t their usual self and you’re worried
  • Your baby has been given medicines like ibuprofen or paracetamol, and it doesn’t bring down their temperature
  • Your baby shows signs of dehydration like dry nappies, no tears when crying and sunken eyes
  • Your baby has other symptoms of being sick like a rash

*This is not a complete list. Always seek medical advice if you are concerned about your child’s symptoms. Speak to a doctor, or pharmacist or call 111. Sometimes babies have a high temperature when they’re teething or after vaccination. If you’re worried, then speak to your doctor.

What to do if your baby has a fever?

It’s not necessary to treat a baby for fever with medicine unless they seem distressed. You can usually look after your baby at home and their temperature should return to normal in 3 or 4 days. If the colour of their skin and lips is normal and they respond normally to you, seem content, are attentive and playing, they smile, stay awake or wake easily and cries normally, then their illness is unlikely to be serious.

Here are some tips to look after your baby, when they have a fever:

• Check on them regularly during the night
• Give them plenty of fluids and check that they’re not dehydrated
• Give them food if they want it
• Try to keep them at home and avoid contact with other people until their temperature is normal 

You can also try giving them either children's paracetamol (from 2 months old) or ibuprofen (from 3 months and weighing over 5kg), such as Nurofen for children if they have a fever. Always read the information leaflet in the medicine packaging and follow all of the instructions before giving medicine to your little one.

Tip: Look out for signs of dehydration when your child has a fever.

Babies and children are more likely to be dehydrated than adults when they’re sick.

If your little one has these signs of dehydration, take them to the GP or to A & E urgently:

• A sunken fontanelle (the soft spot on the top of the head sinks inwards) 
• Dry mouth 
• Sunken eyes 
• No tears when crying
• Fast breathing 
• Cold or blotchy-looking hands and feet
• Seem drowsy 
• Dark yellow pee or no pee in 12 hours

You can lower the chance of dehydration by:
• Giving your child plenty of fluids – start with small sips, you can use a spoon for young children to make it easier to swallow fluids
• Continuing to offer your baby formula or breast milk feeds by giving small amounts more often than usual
• For babies on formula or solid foods - try giving them extra sips of water
• Giving small children their usual diet and offer them food with a high water content like soups, ice lollies or fruit, such as melon

It’s recommended that you call 999 and take a feverish baby for immediate medical attention if they:

• Are extremely agitated, do not stop crying, have a high-pitched cry or seem confused
• Are bothered by light
• Are struggling to breathe
• Suck their stomach in under their ribs
• Have a stiff neck or rash that doesn’t fade when you press a glass against it
• Are drowsy and struggle to wake up
• Have very cold hands and feet
• Have a seizure (fit)
• Have pale, blue or blotchy skin, lips or tongue
• Are not feeding or not responding like they usually do.

Trust your instincts. You know when your baby is not themselves or if it’s an emergency. It’s also good to remember that potentially serious causes of fever are quite rare.
Important Note: If symptoms persist, see your healthcare professional. All information presented on these web pages is not meant to diagnose or prescribe. In all health matters for further information or medical advice, please speak to your GP or a Pharmacist.