A fever in an infant can represent something as simple as a mild virus to something serious like meningitis. A baby with a serious infection can start off looking good, but can get worse fast, so any fever in an infant during the first three months of life requires immediate attention.
Parents may first notice that their baby feels warm. That's called a "tactile temperature" and while a parent's suspicions are sometimes correct, it's important to take the baby's temperature using a thermometer.
According to Dr. Dan Johnson, associate professor and specialist in pediatric infectious diseases at the University of Chicago, parents should avoid the use of thermometers that take the temperature on the forehead or in the ear because they can be inaccurate.
Instead, Johnson recommends a digital thermometer under the arm or in the rectum. Parents should call their doctor if the infant's temperature is 100.5 degrees or more in either location.
Most doctors will want to examine any infant less than 4 weeks old with a fever because infections in very young babies may be more serious than they first appear.
After office hours and on weekends, the doctor may send the family to an emergency department for evaluation. Figuring out the cause of a fever can require extensive testing. The doctor may need to draw blood, collect urine, get a chest x-ray or even do a spinal tap. In some cases, the baby will need to be admitted to the hospital and put on IV antibiotics for a few days.
For babies between 4 and 12 weeks old, some doctors will monitor the child at home and ask the parents to check back in at a specified time. If there is any question about the baby's well-being, the doctor will ask the parents to bring the baby in.
Parents should not give an infant acetaminophen (the active ingredient in Tylenol) or any other fever-reducing medication unless they are directed to do so by their doctor.
Johnson has a few other key pieces of advice for parents.
First, don't hesitate to call your doctor if you have any concerns about your baby's temperature. Your pediatrician is your partner in caring for your baby and won't mind. Second, be sure to follow your doctor's advice. If you don't understand your doctor's plan, ask questions until you do. Lastly, an infant under the age of 3 months with a fever can't wait too long.
Editor's note: This article is only for your information and is not medical advice.
Dr. Lisa Thornton, a mother of three, is director of pediatric rehabilitation at Schwab Rehabilitation Hospital and LaRabida Children’s Hospital. She also is assistant professor of pediatrics at the University of Chicago.
See more of Dr. Thornton's stories here.