You need to measure your child's temperature when she is sick, but older children often resist rectal thermometers. The Illinois Department of Public Health states that a child over age 4 who can understand directions and cooperate is old enough to have her temperature taken in ways other than rectally. It is important to know the differences between taking a child's temperature orally versus under the arm, or axillary, to gain an accurate measurement with the least amount of resistance and drama.
Results
Oral readings are 1 degree warmer than axillary temperatures. The tongue's underside is warmer than the skin, so a child's oral temperature naturally will be higher than his axillary temperature. A healthy child has an oral temperature of 98.6 degrees Fahrenheit and an axillary temperature of 97.6 degrees Fahrenheit, according to Mayo Clinic.
Safety
It is safer to take your child's temperature under his arm rather than orally, especially when using an older glass-and-mercury thermometer. Young children tend to squirm, thrash and bite more often when ill -- increasing the potential for accidental thermometer breakage in the child's mouth. Digital thermometers reduce the risk of shattering but still pose a risk when placed in a very young child's mouth.
Accuracy
Oral temperature readings usually are more accurate. Heavy clothing, bedding, room temperature, bathing and sweating reduce accuracy of temperature readings gained under a child's arm. Conversely, a child drinking fluids, eating soup or ice cream just before receiving a temperature reading, or crying and talking while the thermometer is in his mouth, will affect the oral reading's accuracy. Accuracy of either method heavily depends on the child's environment and emotional stability.
Time
It takes longer to measure a child's temperature under her arm than orally. Depending on thermometer-manufacturer specifications, oral temperature results are available after only three minutes; axillary readings take about five minutes. Five minutes is a long time for a restless child to sit completely still, holding a thermometer in his armpit.
Convenience
Your child may be unable to breathe well while she holds a thermometer under her tongue if she has sinus congestion. It would be more comfortable to measure this child's temperature under her arm. An axillary reading is more convenient than oral measurements for children who have trouble refraining from eating and drinking hot or cold beverages for at least 10 minutes, which would affect oral thermometer results.
