When Does a Fever Become Dangerous for a Baby?

If your baby has a fever, his immune system is fighting an infection or illness 1. Feverish babies feel warm to the touch and may appear sweaty, flushed or pale. Fevers are often the first sign of illness in a baby, according to the North Dakota Department of Health. You can often treat low fevers at home, but you should contact your doctor if your baby has a high fever or is very young 1.


A baby has a fever if her axillary, or armpit temperature is 98.6 degrees Fahrenheit or higher, or if her rectal temperature measures 100.4 degrees Fahrenheit or higher, according to the North Dakota Department of Health. Seek medical attention if your baby is less than 3 months old and has a fever or if your baby has a fever of 101 F or higher 1. In addition, see your doctor if your baby's fever lasts longer than 24 to 48 hours or if her fever comes and goes for a week or more, according to Medline Plus.

Danger Signs

You should also seek medical attention if your baby exhibits other symptoms, such as:

  • not producing tears when crying
  • not urinating
  • sore throat
  • nausea
  • vomiting or earache

Call 911 if your baby seems confused, cannot be awakened easily, has a stiff neck, has trouble breathing, has blue lips or nails or has a seizure.

Taking a Baby's Temperature

Doctors recommend taking your baby's temperature in his armpit, according to the North Dakota Department of Health. Keep the thermometer in his armpit for five minutes before reading the temperature. Read the directions on digital thermometers before use; these thermometers may be less accurate on infants. Your baby's temperature fluctuates throughout the day, so if he has a fever but doesn't seem sick, take off some of his clothing or blankets and take his temperature again in 30 minutes 1.

Home Care

Give babies plenty of liquids when they are feverish, but dilute fruit juice with water. Don't force babies to eat while they have a fever, although some babies may eat bland food. Dress babies in lightweight clothing and ensure the room is comfortably cool. Do not cover feverish babies with extra blankets or clothing. Acetaminophen or ibuprofen may help lower a fever, but call your doctor before giving medication to infants younger than 3 months old. In addition, never give babies aspirin. Lukewarm sponge baths may help but don't use cold water or alcohol rubs, which can make babies too cold.