Infrared assessment of human facial temperature in the presence and absence of common cosmetics

Using a sensitive research-grade infrared camera, we find that common facial cosmetics and lotions mask skin temperature in assays of the human forehead. We test a family of 10 commonly-used cosmetic products and find that volatile liquids and creams lower thermal skin temperature by at least 2 C for up to 5-10 min and at least 1 C for up to 20 min, respectively. Powder and cream that contains brightening agent lower indefinitely the skin temperature sensed by infrared camera. With the qualification that these experiments were performed in a controlled laboratory setting rather than the mass crowd screening environment where infrared temperature sensing of humans sees widespread use, our tests suggest that for human subjects whose face was treated with certain cosmetics and lotions, infrared-based screening for elevated facial temperature (fever) can be unreliable.