Fever Facts

By Alexa Joy Sherman

I’ve taken my son’s temperature dozens of times since he was born, but one thing that never gets easier is seeing the number on the thermometer soar. The higher it climbs, the more concerned I become—and I’m hardly alone. Fever is one of the most common reasons why parents visit emergency rooms with an infant or child, according to the American College of Emergency Physicians (ACEP), and it’s the top reason why they call their child’s doctor, says Ari Brown, M.D., a pediatrician in Austin, Texas, and coauthor of Toddler 411: Clear Answers & Smart Advice for Your Toddler (Windsor Peak Press, 2006).

Put the number in perspective
Most people have been taught that any temperature over 98.6 degrees Fahrenheit constitutes a fever—but that’s not entirely accurate. In fact, a child’s body temperature can fluctuate by one to two degrees throughout the day, notes the National Institutes of Health (NIH). It tends to be lowest in the morning and highest at night. The ACEP considers a fever to be a rectal temperature above 100.4 degrees F or an oral temperature above 99.5 degrees F. Meanwhile, fever is actually a good thing. The bacteria and viruses that cause infection thrive at a normal body temperature, but become threatened under more sweltering conditions.

A fever also prompts your immune system to produce more white blood cells, antibodies and other infection fighting agents, explains the NIH. It’s important to understand that the fever itself will rarely be harmful to your child. “Fever is not a disease, and kids will not self-destruct with a fever,” says Brown. If caused by infection, it will rarely go over 105 degrees F (unless the child gets overheated by excessively heavy clothing or other environmental conditions), and brain damage generally will not occur unless the fever rises above 107.6 degrees F, according to the NIH.