Baby Health: Fevers in Infants
Many conditions—such as an ear infection, a common cold, the flu, a urinary tract infection or pneumonia—may cause a child to develop a fever. Fevers are generally harmless and actually help your child fight infection. They can be considered a sign that your child's immune system is working and her body is trying to rid itself of the infection.
However, fever in infants (babies younger than 1 year old) may also signal a serious infection. Young infants (under 3 months of age) who have any fever at all should be seen by a doctor to determine the cause and treat it. In infants over 3 months old, you should contact your pediatrician any time your child runs a fever associated with abnormal drowsiness, a stiff neck, drooling, difficulty breathing or a seizure, or any time your child has a fever and simply seems severely ill.
Most pediatricians consider any thermometer reading above 100.4 degrees Fahrenheit (38 degrees Celsius) a sign of a fever. This number may vary depending on the type of thermometer (ear, oral, rectal) and body site (armpit, ear, mouth, rectum) used for taking your child's temperature. If you need to call your pediatrician about a fever, be sure to say which method and body site you used in taking your child's temperature.