What is a fever?
Fever is often the body’s response to a bacterial or viral infection. Fevers turn on the body’s immune system. Fevers are one of the body’s protective mechanisms.
Most fevers between 100°F and 104°F (38°C to 40°C) are good for sick children and help the body fight infection. The exception is babies less than 2 months of age. They should be seen by a healthcare provider right away.
Fever is generally harmless, but your child may not feel well because of the infection that is causing the fever. Fevers with infections don’t cause brain damage. Only body temperatures over 108°F (42°C) can cause brain damage. The body temperature goes this high only with extreme environmental temperatures (for example, if a child is left in a car in hot weather).
What temperature is considered a fever?
Your child has a fever if his or her rectal or oral temperature over 100.4 ˚F (38.0˚C).
A rectal temperature is taken with the thermometer tip inserted into your child’s bottom with a small amount of lubricating jelly
An oral temperature is taken with the thermometer tip under your child’s tongue with mouth closed
How should I treat my child’s fever?
If your child is less than 2 months old, see a doctor urgently if he or she has a fever.
For children over 2 months old, fevers need to be treated only if they cause discomfort. Usually that means fever over 102°F or 103°F (39°C or 39.4°C).
Because the brain has a thermostat, fevers from infection usually top out at 103°F to 104°F (39.4°C to 40°C).
With treatment, fevers usually come down 2° or 3°F (1.1° or 1.7°C)
How the body responds to the medication does not indicate the seriousness of the infection.
If your child is older than 2 months you may treat the fever with Acetaminophen (acetaminophen dosage chart). You only need to treat a fever if your child appears uncomfortable (has difficulty sleeping, is crying and/or not eating). The goal is to make your child comfortable, not to bring down the temperature
If your child is older than 6 months you may give Acetaminophen or Ibuprofen (ibuprofen dosing chart). Give medication only if your child appears uncomfortable
Other things you can do to make your child more comfortable are:
- Offer extra fluids (water, juice) in small but frequent amounts
- Give lukewarm sponge baths
- Put cool washcloths on forehead/back of neck
- Do not use aspirin for children under 18 years of age
The fever will normally last for 2 or 3 days with most viral infections. Therefore, when the fever medicine wears off, the fever will return and need to be treated again. The fever will go away and not return once your child’s body overpowers the virus (usually by the fourth day).
When should I call my doctor if my child has a fever?
Call your doctor if any of the following are true:
- Your child is 2 months old or younger
- Your child has had a fever for greater than three days
- Your child develops other symptoms including:
- increased work of breathing
- difficult or painful urination
- not responding normally to you
- unwilling to eat or drink
When should I take my child to the emergency department for a fever?
Take your child to the nearest emergency room if any of the following are true:
- Your child is 2 months or younger and has a fever
- Your child looks or acts very sick with their fever and has other symptoms such as:
- difficult to wake up
- stiff neck
- trouble breathing
- unable to drink fluids
- crying without tears
- dry diaper for at least 8 hours
- dry mouth with cracked lips
Written/reviewed by Sara Laule, MD
Updated March 2017