Kommentar zu Wajikra 13:43

כמראה צרעת עור בשר AS THE COLOUR OF LEPROSY IN THE SKIN OF THE FLESH — it is like the colour of the leprosy which is mentioned in the section dealing with the plague on the skin of the flesh (v. 2): “When a man hath in the skin of his flesh …”.What is stated about that? That it makes one unclean by reason of four shades of white, and that it is subject to the law of quarantine during two weeks. And it is not to be treated like the colour of the leprosy mentioned in the case of the boil (v 18) or burn (v. 24) which though also unclean by reason of four shades of white are, however, subject to the law of quarantine for one week only, (i. e if at the end of the week there is neither white hair, nor has it spread the priest at once declares him clean); nor must it be treated as the colour of נתקין on a spot where hair grows — which do not make a person unclean by cause of four colours: a שאת and its subspecies, and that of a בהרת and its subspecies.