Testing the validity of erythema detection algorithms

Dermatology has quantified skin color for monitoring progress of treatments. The most common and effective means of erythema detection is visual inspection of the skin. However, for people with darkly pigmented skin, erythema can be masked by melanin. Tissue Reflectance Spectroscopy (TRS) is a noninvasive method of quantifying skin color. Most commonly, TRS quantifies erythema caused by cosmetics, topical ointments, UV light, or other irritants. Recently, TRS has been used to characterize the presence of erythema due to reactive hyperemia or Stage I pressure ulcers. The objective of this study was to compare the reliability and validity of erythema detection algorithms by determining their sensitivity and specificity. Two algorithms, Diffey and Helen Hayes Hospital (HHH), had sensitivity exceeding 85% and specificity exceeding 75%, but most algorithms demonstrated adequate validity across all subjects. The validity of the HHH algorithm did not change with the skin pigmentation of the subject. The results of this comparison will be useful to researchers interested in using TRS to detect erythema in people with different skin pigment levels.