The disorder is prevalent in Central and South America, in the Far East, and in the tropical countries of Asia and Africa. There are about 4,000 cases in the United States. Leprosy is contagious through the respiratory tract, but the danger of catching it from another person is very slight. Relatively few persons exposed to the disease develop it. To contract leprosy, a person must have low resistance and live in contact with a person whose body contains large numbers of the germs.
Children are more likely to become infected than are adults.
There are two main forms of leprosy, tuberculoid leprosy and lepromatous leprosy. Tuberculoid leprosy appears as an infection around nerve endings, causing gradual loss of feeling and the appearance of pale areas on the skin where sensation is reduced. The nerves may be felt as thickened, tender, rope-like structures. This may lead to partial paralysis, producing wrist drop or foot drop and sometimes local areas of ulceration. The normal pigmentation in some areas on the skin is lost, and the skin becomes slightly reddened.