Leviticus 13:12,13

And if a leprosy break out abroad. — There were, however, two phases of this returned distemper which exempted the patient from uncleanness. If the leprosy suddenly covered the whole body so that the patient became perfectly white, in which case there could be no appearance of live flesh, then he was clean. This indicated the crisis, as the whole evil matter thus brought to the surface formed itself into a scale, which dried and peeled off.