It depends on the child’s age:
- in children under five, a fever (high temperature) is a temperature over 37.5C (99.5F)
- in children five and over, a fever is a temperature of 38C (100.4F) or over
You can use a thermometer to find out if your child has a fever. For more information, see How do I take someone’s temperature?
Causes of fever
Most fevers are caused by an infection or other illness.
Fever helps your body fight infections by stimulating the body’s natural defences. By increasing the body’s temperature, a fever makes it harder for the bacteria and viruses that cause infections to survive.
Conditions that can cause fevers include:
Other things that may raise the temperature of a baby or child include:
- overheating because of too much bedding or clothing
- teething
- being vaccinated
Treating a fever
You can usually treat fever in young children at home using infant paracetamol. For more information, see birth to five: treating a high temperature.
Getting help
If you’re worried about your child, trust your instincts. Speak to your GP or call NHS Direct on 0845 4647.
If your GP surgery is closed, contact the out-of-hours service. If you’re still concerned, or if your GP or out-of-hours service can’t come quickly enough, take your child straight to the nearest hospital’s accident and emergency department.
Other symptoms
Symptoms that may be a sign of a more serious illness include:
- being unusually sleepy
- not drinking for more than eight hours
- having an unusual rash
For more signs of serious illness and advice on when to call an ambulance for your child, see birth to five: recognising signs of serious illness.
Febrile convulsions
Febrile convulsions are seizures (or fits) that sometimes happen in children who have a high temperature. They are most common in children under three and are rare after the age of six.
Febrile convulsions can happen as a result of any illness that causes a high temperature. They can be frightening for parents but look much worse than they actually are. Febrile convulsions rarely cause any long-term complications.
If the seizure has not stopped within three minutes, call 999. If it stops, but it was your child’s first ever seizure, take them to the nearest accident and emergency department to be checked over.
See the Health A-Z topic about febrile convulsions for more information.
Read the answers to more questions about children’s health.
Further information:
