11 it is a chronic skin disease and the priest shall pronounce them unclean. He is not to isolate them, because they are already unclean.

Read Leviticus 13:11 Using Other Translations

It is an old leprosy in the skin of his flesh, and the priest shall pronounce him unclean, and shall not shut him up: for he is unclean.
it is a chronic leprous disease in the skin of his body, and the priest shall pronounce him unclean. He shall not shut him up, for he is unclean.
it is a chronic skin disease, and the priest must pronounce the person ceremonially unclean. In such cases the person need not be quarantined, for it is obvious that the skin is defiled by the disease.