Leviticus 13:2-6

“If anyone has a swelling or a rash or discolored skin that might develop into a serious skin disease, that person must be brought to Aaron the priest or to one of his sons. The priest will examine the affected area of the skin. If the hair in the affected area has turned white and the problem appears to be more than skin-deep, it is a serious skin disease, and the priest who examines it must pronounce the person ceremonially unclean. “But if the affected area of the skin is only a white discoloration and does not appear to be more than skin-deep, and if the hair on the spot has not turned white, the priest will quarantine the person for seven days. On the seventh day the priest will make another examination. If he finds the affected area has not changed and the problem has not spread on the skin, the priest will quarantine the person for seven more days. On the seventh day the priest will make another examination. If he finds the affected area has faded and has not spread, the priest will pronounce the person ceremonially clean. It was only a rash. The person’s clothing must be washed, and the person will be ceremonially clean.