Leviticus 13:1-3

The LORD said to Moses and Aaron, “When anyone has a swelling or a rash or a shiny spot on their skin that may be a defiling skin disease, they must be brought to Aaron the priest or to one of his sons who is a priest. The priest is to examine the sore on the skin, and if the hair in the sore has turned white and the sore appears to be more than skin deep, it is a defiling skin disease. When the priest examines that person, he shall pronounce them ceremonially unclean.