A difference of 5 degrees C between ear and rectal temperatures in a febrile patient.

A 4-year-old boy with a history of seizures triggered by fever presented at an emergency department (ED) with tachycardia, skin vasoconstriction, and a rectal temperature of 42.2 degrees C. However, his ear temperature (as repeatedly measured in two ears, by two experienced nurses, and with two infrared thermometers) was between 36.4 degrees C and 37.6 degrees C. Antipyretic therapy resulted in skin vasodilation, a rapid decrease of rectal temperature, restoration of heart rate, and disappearance of the difference between the two temperatures. Seizures did not occur. This case shows that infrared ear thermometry cannot be recommended in EDs as the procedure of choice for detecting fever in small children, especially when they are vasoconstricted.