Hansen’s disease

A chronic bacterial infection, also called leprosy, that damages nerves, mainly in the limbs and facial area, and may cause skin damage. The disease is caused by a bacterium,, which is spread in droplets of nasal mucus. Hansen’s disease is not highly contagious, and a person is infectious only in the early stages. Prolonged close contact puts people at risk. The disease is most prevalent in Asia, Central America, South America, and Africa. Hansen’s disease has a long incubation period – about 3–5 years. There are 2 main types: the lepromatous type, in which damage is widespread, progressive, and severe; and the tuberculoid type, which is milder. In both types, damage is initially confined to peripheral nerves supplying the skin and muscles. Skin areas supplied by affected nerves become lighter or darker and sensation and sweating are reduced. As the disease progresses, the peripheral nerves swell and become tender. Hands, feet, and facial skin eventually become numb and muscles become paralysed, leading to deformity. Other possible features include blindness, destruction of bone, and sterility. The presence of the causative bacteria is confirmed by a skin biopsy. Drug treatment may be with a combination of dapsone, rifampicin, and clofazimine, which kills most of the bacteria in a few days. Any damage that has occurred before treatment, however, is irreversible. Plastic surgery may be necessary to correct deformities; and nerve and tendon transplants may improve the function of damaged limbs.