A normal temperature is about 37oC (98oF) when taken orally (by mouth). Temperatures taken rectally (by rectum) usually run 0.5oC higher than those taken orally. So a normal temperature is about 37.5oC (99.5oF) when taken rectally. But temperatures may vary during the day, even in healthy children. Many doctors define a fever as an oral temperature above 37.8oC (100oF) or a rectal temperature above 38.0oC (101oF) or an axillary (by ear) temperature above 37.2oC (99oF) (ear temperatures are not accurate in children under 6 months of age and often not recommended in children less than 1 to 2 years of age).
The best way to take child's temperature
You may think you can tell if your child has a fever by touching his or her forehead. It may alert you to a fever, but this isn't an accurate way to tell. Fever strips, which are placed on the child's forehead, are also not accurate.
The best ways to take your child's temperature are orally, rectally, by placing the bulb of the thermometer under the arm (axillary temperature) or using an ear thermometer. For children under 2, you can check by doing an axillary temperature and do a rectal temperature if there is a fever, in order to get an accurate measurement.
Some tips on taking child's temperature:
- If you are using a mercury thermometer, the mercury of the thermometer should be below 35oC (95oF) before taking a temperature. You can run cool water over the thermometer to lower the reading. Some thermometers must be shaken to lower the reading.
- Don't bundle your baby or child up too tightly before taking the temperature.
- Never leave your child alone while taking the temperature.
- Be sure you use the right thermometer. Rectal thermometers are thicker than oral thermometers (the bulb is fatter). Digital thermometers are usually used in the mouth or under the arm.
- If you're taking your child's temperature orally, place the end of the thermometer under the tongue and leave it there for two minutes. Don't let your child bite on the thermometer. The child must be old enough to cooperate and often this method is used in children over 4 to 5 years of age. Digital thermometers may beep when they are ready to be read.
- If you're taking your child's temperature rectally, coat the tip of the thermometer with petroleum jelly (Vaseline) and insert it half an inch into the rectum. Hold the thermometer still for two minutes. Never let go of the thermometer. This method often works best with infants. Some doctors prefer the axillary method for safety reasons.
- Axillary temperatures are not always accurate but this is a safe way to take the temperature of toddlers and children under 4 years of age. Place the bulb of a glass thermometer in the child's armpit and hold the arm against the child's body so that the bulb is covered. Keep the bulb in place for at least 3 minutes.
- Ear temperatures - Uses a special thermometer that quickly takes the temperature from the eardrum (tympanic membrane). These are not accurate in infants and the machines can be expensive.
- After you're done using the thermometer, wash it in cool, soapy water or according to the manufacturer's directions.