@irontoenail - I think that people with leprosy end up losing the pain sensors in their limbs as well. That's why they have the reputation for "rotting away" even though they don't actually lose anything from the leprosy itself. I've heard that they have to spend a lot of time double checking all their extremities to ensure that none of them are being injured, because there is no other way to tell.
They end up getting so many injuries in the areas that go numb that eventually they get permanent damage. The body has fewer defenses for other diseases as well.
It's a really terrible disease and we are lucky to live in a world where it can basically be cured now.