Fever is the body's
normal and healthy reaction to infection and other illnesses, both minor and
serious. Fevers help the body fight infection. Fever is a symptom, not a
disease. In most cases, fever means your child has a minor illness. Often you
must look at your child's other symptoms to determine how serious the illness
is. Although it may be scary when your child's temperature goes up, fever is
The average normal body
temperature is about
98.6 °F (37 °C). It usually rises
during the day from a low of
97.4 °F (36.3 °C) in the morning
to a high of 99.6 °F (37.6 °C) in the late afternoon. Each child has a normal temperature
range that may be different from another child's. Mild increases to
100.4 °F (38 °C) can be caused by exercising,
wearing too many clothes, taking a hot bath, or being outside in hot
Temperature varies depending on how you take it. The most common ways to measure it are:
- Under the tongue.
- In the armpit.
- In the rectum.
- In the ear.
You can also use:
- Forehead thermometers.
- Pacifier thermometers.
Some methods may not be as reliable or accurate as others. For information about taking
accurate temperatures, see the topic
If you think your child
has a fever but you are not able to measure his or her temperature, it is
important to look for other symptoms of illness.
Children tend to
run higher fevers than adults. The degree of fever may not indicate how serious
your child's illness is. With a minor illness, such as a cold, a child may have
a temperature of 104 °F (40 °C), while a very serious infection may not
cause a fever or may cause only a mild fever. With many illnesses, a fever temperature can go up and down very quickly and often, so be sure to look for other
symptoms along with the fever.
Babies with a fever often have an infection caused by a virus, such as a cold or the flu. Infections caused by bacteria, such as a urinary infection or bacterial pneumonia, also can cause a fever. Babies younger than 3 months should be seen by a doctor anytime they have a fever because they can get extremely sick quickly.