Skin temperature, as measured by infrared radiation, is increased by the active hyperemia associated with a positive immediate skin test reaction in allergic individuals. An objective method for reading, recording, and quantitating such increases in temperature is possible with the use of a new instrument. This method may prove to be especially useful in identifying the degree of reaction on heavily pigmented skins, where the erythema of the reactions is difficult or impossible to see.
Kaufman HS, Sulzberger MB. Infrared Thermometry for Reading Reactions on Darkly Pigmented Skin. JAMA. 1967;202(2):91-93. doi:10.1001/jama.1967.03130150059007