The kohen is to examine him on the seventh day. If it has spread in the skin, then the kohen is to pronounce him unclean. It is the plague of tza'arat.
Then he is to reexamine the plague on the seventh day. If the plague has spread in the garment, either in the weaving, the texture or the leather, whatever the use for the leather may be, the plague is a destructive mildew. It is unclean.