Leprosy is like sin in many ways. There are some good reasons why many ancient rabbis considered a leper as someone who was already dead.
It begins as nothing.
It is painless in its first stages.
It grows slowly.
It is contagious.
It often remits for a while and then returns.
It numbs the senses—one cannot feel in the afflicted area.
It causes decay and deformity.
It gives a person a repulsive appearance.
It causes separation and death.