Leviticus 13:29-13:39

If a man or a woman has an affection on the head or in the beard, the priest shall examine the affection. If it appears to go deeper than the skin and there is thin yellow hair in it, the priest shall pronounce him unclean; it is a scall, a scaly eruption in the hair or beard. But if the priest finds that the scall affection does not appear to go deeper than the skin, yet there is no black hair in it, the priest shall isolate the person with the scall affection for seven days. On the seventh day the priest shall examine the affection. If the scall has not spread and no yellow hair has appeared in it, and the scall does not appear to go deeper than the skin, the person with the scall shall shave himself, but without shaving the scall; the priest shall isolate him for another seven days. On the seventh day the priest shall examine the scall. If the scall has not spread on the skin, and does not appear to go deeper than the skin, the priest shall pronounce him clean; he shall wash his clothes, and he shall be clean. If, however, the scall should spread on the skin after he has been pronounced clean, the priest shall examine him. If the scall has spread on the skin, the priest need not look for yellow hair: he is unclean. But if the scall has remained unchanged in color, and black hair has grown in it, the scall is healed; he is clean. The priest shall pronounce him clean. If a man or a woman has the skin of the body streaked with white discolorations, and the priest sees that the discolorations on the skin of the body are of a dull white, it is a tetter broken out on the skin; he is clean.