Leprosy in East Asia is believed to be caused by (a) bad geomancy or (b) bad karma. People with leprosy are marginalised and discriminated against. Lepers are restricted to living in leper colonies, remote villages isolated from the rest of the population, or even secluded on islands (esp. in Korea). Lepers are deprived of their inheritance rights.
Because of fear, stigma, and revulsion toward lepers, the latter may travel quite unhinderedly— constables or guards, for instance, will refuse to search their body and belongings. On the other hand, what explanation can they provide for not being restricted to their colony?
If you're using The Celestial Empire, the Status skill of a leper is limited to 20%. If you're using Monsters & Magic, the Status attribute of a leper is limited to 4.