Leviticus 13:30

then the priest shall examine the plague; and behold, if its appearance is deeper than the skin, and the hair in it is yellow and thin, then the priest shall pronounce him unclean. It is an itch. It is leprosy of the head or of the beard.

Then the priest shall see the plague: and, behold, if it be in sight deeper than the skin; and there be in it a yellow thin hair; then the priest shall pronounce him unclean: it is a dry scall, even a leprosy upon the head or beard.