Leviticus 13:3 - Joseph Benson’s Commentary on the Old and New Testaments

The priest shall look on the plague In some dubious cases, the priest might find it convenient to take the judgment of physicians, or of persons who understood the theory of diseases better than himself; but, as he was to admit to or exclude from the sanctuary, he alone was to give judgment, and pronounce who were clean or unclean, and, as such, to be admitted or excluded. When the hair is turned white He begins with the last of the three marks of a leprosy, namely, the bright spot. The reason of the hair's turning white is thus assigned by Calmet, in his Dissertation on the Leprosy: “The flesh,” says he, “ceasing to receive its proper nourishment from the blood, which gave it its former vivid colour, the hair, which has its root in the corrupted, empoverished glands, becomes likewise ill-nourished, and so grows whitish and slender, like a plant in stony, parched ground.” His flesh For the leprosy consumed both the skin and the flesh.