Leviticus 13
3 Ref and the priest shall look on the plague in the skin of the flesh: and if the hair in the plague be turned white, and the appearance of the plague be deeper than the skin of his flesh, it is the plague of leprosy; and the priest shall look on him, and pronounce him unclean.
4 Ref And if the bright spot be white in the skin of his flesh, and the appearance thereof be not deeper than the skin, and the hair thereof be not turned white, then the priest shall shut up `him that hath' the plague seven days: