What causes a fever?

A high temperature or fever is common in childhood and is usually caused by a viral infection. These can include common illnesses such as chills, colds, coughs, ear infections, flu or diarrhoea. Sometimes viral infections cause more serious illnesses. Bacterial infections are less common than viral infections but can also cause high temperatures. Bacterial infections, such as pneumonia or meningitis are extremely serious and must receive medical attention immediately so if you think your child's high temperature is caused by something of this nature you should seek medical help as soon as possible.

What constitutes a fever?

Normal body temperature ranges between 36-36.8 degrees C (96.8-98.2 degrees F). If your child has a high temperature, ie over 38 degrees C or 100.4 F then they have a fever; however any temperature over 37 degrees is considered a high temperature. A child with a high temperature may look quite unwell or flushed, and may seem irritable. 

How do I know it's not serious?

Most high temperatures are not caused by serious illness and will often come down quickly without treatment. You may be surprised to see your child playing or seeming quite well again once their temperature returns to normal - they won't necessarily be completely over their illness or infection but it's a good sign if your child has responded to their treatment and their symptoms have been alleviated.

As a general rule, a child with a serious infection, such as meningitis, will usually become worse and more ill, even after appropriate treatment to try and alleviate their symptoms. If their temperature remains high and they develop other worrying symptoms, such as breathing problems, headaches, drowsiness, convulsions or rashes, you should seek medical advice as soon as possible. Take a look at our page on Poorly Baby: When to Get Help for further information.

How can I treat a high temperature?

  • Your child should drink plenty of fluids to keep them hydrated. Water is the best choice.
  • Make sure your child is lightly dressed, if the room they're in is normal 'room temperature'. You should not wrap up a feverish child as they may overheat. Try to keep some fresh air circulating, but avoid putting your child right in front of a fan or another source of very cold air. Open a window  slightly or place a fan on the other side of the room.Treating a fever in children
  • Never 'cold-sponge' - this used to be a popular method for lowering temperatures but is now discouraged as blood vessels under the skin may become narrower if the wateris too cold, which in turn reduces heat lost from the body and can trap heat in deeper parts of the body, leading to an increase in body temperature.
  • Try to ensure your child gets plenty of rest.
  • Most fevers last between 2 and 3 days. Check your child's temperature regularly and seek help if their symptoms are getting worse, or of there is no imporovement after 2-3 days.
  • If your child's symptoms do not improve despite following these instructions, seek medical advice. Do not let a high temperature go on for longer than 3 days without seeking help, and always get help immediately if you think your child may be suffering from a bacterial infection. Always trust your instincts if you think something is not right. Call NHS Direct on 0845 4647.
  • Give your child the appropriate dose of ibuprofen or paracetamol - find out more about treating your child with these medicines on our dedicated page, which provides a full list of medicines which are safe for babies and young children to take. NICE guidlines say that either paracetamol or ibuprofen can be used to reduce temperature in children with fever, but they should NOT be administered at the same time (this advice was published in March 2011.)
  • Do not give your child Paracetamol and ibuprofen alternately. However, if you have tried using one of the two medicines initially and your child has not improved you may consider using the other type of medicine to see if that works better for your child.

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