Leviticus 13:2-3

2“When a man has a swelling on the skin of his body or a scab or a bright spot, and it becomes the plague-mark of tza'arat in his flesh, then he shall be brought to Aaron the kohen, or to one of his sons, the kohanim.

3The kohen is to examine the plague of tza'arat on his skin, and if the hair in the plague has turned white, and the appearance of the plague is deeper than the body’s skin, it is the plague of tza'arat. Thus the kohen should examine him and pronounce him unclean.