A fever is a temperature of 100.4 or higher. The best/most accurate way to check a temperature in infants and young children is a rectal temperature. Babies who are less than 1 month old and have a fever need to be seen right away. Be sure to talk to your child's physician about appropriate weight-based medication dosing for Acetaminophen or Ibuprofen, which can be used to reduce fever.
You should contact the physician's office if there are any of the following signs or symptoms along with fever: rapid breathing that doesn't go away, blue coloring, the skin around the ribs pulls in when the child is breathing (retractions), your child cannot be woken up, there is a decrease in appetite, or your child is having difficulty peeing or pooping.