Fever in Infants


Fever is an increase in body temperature above the normal level of about 98.6? Fahrenheit or 37? Celsius. Fever usually indicates an infection, but may also occur in other disorders such as some types of cancer or arthritis. Fever in infants (babies younger than 1 year old), especially those younger than 3 months, can signal a serious infection. Such young infants who have fever should be seen by a doctor to determine the cause and treat it.



  • Use a rectal thermometer with the bulb end coated with petroleum jelly.

  • Insert it one inch into your baby's rectum while the baby rests on his or her stomach (on your lap or on a changing table).

  • Do not let go of the thermometer because if the baby moves, the thermometer can move also and possibly injure the baby. Proper use of a rectal thermometer will not harm your baby.

  • Leave the thermometer in place for 2 minutes, remove it, and read it.

  • If it is impossible to use a rectal thermometer, an axillary (armpit) temperature can be taken. Usually axillary temperatures are one full degree less than rectal temperatures.



Keep the room temperature comfortable and dress your infant in loose, lightweight clothing. Do not wrap the baby tightly in blankets. Provide plenty of fluid for the baby to drink. If the fever is high or the infant appears uncomfortable, you may sponge the baby with tepid water (barely warm to the back of your wrist). Do not use alcohol to sponge him or her because it can be absorbed through the skin and cause harm. Antipyretic (fever-lowering) medications, such as acetaminophen, may be given on the advice of your doctor. Do not give aspirin to lower a child's fever because aspirin may be associated with the development of Reye syndrome, a potentially fatal medical problem.



  • Fever in an infant younger than 3 months.

  • High fever (greater than 101? Fahrenheit or 38.3? Celsius).

  • Fever associated with abnormal drowsiness, a stiff neck, or the child's appearing severely ill ? this may signal meningitis, a serious infection of the covering of the brain and spinal cord.

  • Fever with drooling or difficulty breathing ? this may indicate epiglottitis, a serious infection of the back of the throat.

  • Fever with a seizure.



About 4% of children younger than 5 years experience a seizure (convulsion) while they have a fever. These are called febrile seizures. Usually they are harmless to the child, with no lasting effects, but should be evaluated by a physician. These seizures are not considered epilepsy (recurrent seizures that occur without a fever).


Adapted with permission from JAMA Patient Page, March 2004 (not copyrighted).