At what point does a preschooler’s or baby’s temperature cross over to that of a fever?

This is something that every parent should know. A fever likely means that your child is fighting off an infection.

“A temperature of 99 is not a fever and not urgent,” says Irene Tien, MD, a board-certified pediatric ER physician with Mass General Brigham in MA.

“Infants can have temperatures of 99F normally,” continues Dr. Tien. “Fever in a child is not urgent in general.

“If your child is very young (i.e., under three months of age), there needs to be a phone call to the pediatrician if the temperature is 100.4F or higher.

“If the child is older than three months, we don’t really think of a fever as needing a special evaluation beyond a physical exam unless it is 102.2F or higher.

“Fever in kids is complicated, but the height of fever is not a marker for concern except is some cases of young infants.

The Real Threats four year old

“We worry about temperatures being too high when children are left in enclosed spaces, like a car,” points out Dr. Tien. And this situation happens way too often!

“But the height of fevers from infection do not associate with the severity of the infection. Rather, some children are more prone to very high fevers than other children.”

If there are other symptoms such as a nagging cough, vomiting, bad stomach pain, respiratory distress or severe weakness, take your child to the emergency room.

In practice for 20+ years, Dr. Tien is a leading medical voice on social media, providing the public with accurate information to empower them to live their healthiest life.
Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.