Here's What's Hot With Thermometers

Buying a thermometer isn't as easy as it used to be. You face an array of choices. But the decision doesn't have to be hard. Like temperature, it's a matter of degrees.

You can choose from these types of thermometers:

• Oral, rectal or under the arm. Digital thermometers can take a body temperature orally, rectally or in the armpit. The peak temperature registers in about 30 seconds, often signaled by a beep. A rectal temperature reading is the most accurate, but if done carefully, oral and armpit readings are adequate.

• Ear. These are also called tympanic thermometers. Ear thermometers can be expensive and may be inaccurate. "They are affected by how well they are placed in the ear, by ear wax and by battery quality," says Patricia M. Edwards, M.D., a spokeswoman for the American Academy of Pediatrics (AAP).

• Forehead. Called a temporal artery thermometer, this type takes the temperature on the skin above an artery in the forehead. It's accurate, quick and easy to use. Ease of use makes it handy for parents with very young children who squirm. "Simply sweep it across their forehead [and the temple] and you get an immediate result," Dr. Edwards says.

You can also buy a thermometer that looks like a pacifier. The drawback to this type is that the child must hold the pacifier in one place in his or her mouth for about three minutes. The temperature reading also is usually slightly lower than with a digital oral thermometer, so you should add a half a degree to the result.

Temperature strips placed on the skin are another way to tell body temperature, but they don't give an exact number. Instead, they change color as body temperature changes.

No more mercury

The old mercury thermometer is very precise, but the AAP says you shouldn't use one. Mercury is highly toxic, and a broken thermometer can cause trouble. Newer glass thermometers use a mercury substitute.

Once you pick a thermometer, when should you use it? "Take the temp if the child feels hot and fussy," Dr. Edwards says. "We tell parents that a fever as high as 104 is not unusual in a young child 1 year old and up." If the child looks relatively well, doctors suggest a dose of ibuprofen and waiting an hour to see if the temperature falls. One key exception: In an infant 2 months old or younger, call the doctor about a rectal temperature greater than 100.5 degrees F.

The best place to use the thermometer depends on the child's age:

• Infants. You should start out taking an armpit reading for an infant younger than 3 months. If the temperature is higher than 99 degrees F, take a rectal reading. To do this, put some petroleum jelly on the end of a rectal thermometer. Place the thermometer half an inch to one inch inside the baby's rectum, says the AAP.

• Babies to preschoolers. Take a rectal reading, or use an ear or pacifier thermometer.

• School-age. By this age, most children can hold an oral thermometer in the mouth long enough to get an accurate reading.

What's a fever?

Determining whether your child has a fever depends on where you take the child's temperature:

• Oral = fever is 99.5 degrees F or higher

• Under the arm = fever is 99 degrees F or higher

• Rectal = fever is 100.4 degrees F or higher

A fever won't tell you how sick your child is, however. Some illnesses such as a cold or other viral infection may cause a high temperature. Another type of infection may not cause a fever at all, yet be much more serious. Always call your health care provider if you are concerned about your child's health or have questions about the seriousness of a fever.