Among digital thermometers, a popular though expensive option is the ear thermometer, which measures the temperature in the ear canal. This instrument is considered quick, comfortable and relatively accurate, but Dr. Lorraine Stern, a clinical professor of pediatrics at the University of California Los Angeles, cautions that it doesn't work well in small infants. This is because their soft ear canals may provide a reading that is too low.
For infants under 6 months old, doctors recommend using a rectal thermometer. This is also a good option for children under 4 or 5 years old, who are too young to properly use an oral thermometer. Some parents may prefer the axillary thermometer, which measures the temperature under the armpit, though one study found that the normal axillary temperature runs low and should be interpreted with caution.
Stern warns against using forehead thermometers, which are sold in strips, and pacifier-thermometers, because neither of them will give an accurate reading.
She also reminds parents that, except for infants, a reading from a thermometer shouldn’t be the only factor that determines if a child needs to see a doctor. "A child with a 101° F fever who is moaning and pale maybe sicker than a child with an 103° F fever who is running around," Stern explains. While a fever is often scary for the parent and uncomfortable for the child, it is part of the way the body fights infection.
Besides weighing factors such as your child's appearance and energy level, parents should also consider their child's age and the length of time they've had the fever. "In infants under 2 months with a fever, bring them in right away," Stern says. "In a 4-year-old, you can wait a day or two and see what happens if they don't look bad."
"It the child's temperature seems too high or too low, check it with another method,” Stern continues. “And you may have to combine such things as the thermometer reading, how your child looks and even putting your lips on his or her forehead."