Fever is a rise in body temperature above the normal range, and most of the time it is part of the fight against infection. Measuring it correctly reduces both unnecessary use of medication and unnecessary worry.

Methods and how reliable they are

Method Notes
Rectal Accepted as the most reliable in young babies; on a physician's advice
Underarm Common and practical; can be affected by the room temperature
Ear (tympanic) Fast; earwax and a wrong angle can change the reading
Forehead (non-contact) Practical; sweating and the room temperature affect the reading
Oral In older children; wait a while after hot or cold drinks

Mercury thermometers are not used; they carry the risk of breaking and of contact with mercury.

For an accurate reading

  • If the child is dressed, undress them and wait a while before measuring
  • Wait a few minutes after crying or running around
  • Within the same day, measure with the same method where possible
  • Note the time and the value of the reading; it is valuable for the physician

What to watch for in a child with a fever

The child's overall condition matters as much as how high the fever is: alertness, fluid intake, urine output and breathing are monitored.

A physician should be consulted without delay in the following situations: fever in a baby younger than three months, fever together with drowsiness, bluish discolouration, rapid and laboured breathing, a rash, neck stiffness, a seizure, or an inability to take fluids.