Only a small minority of those exposed to M. leprae develop the disease. The incubation period is 3–5 years or longer. The major clinical manifestations involve skin and nerves: the former range from depigmented, often anaesthetic areas, to massive nodules; nerve involvement ranges from localised nerve swelling(s) to extensive areas of anaesthesia. Advanced nerve destruction gives rise to severe deformities: foot-drop, wrist-drop, claw-foot, extensive ulceration of the extremities with loss of ?ngers and toes, and bone changes. Eye involvement can produce blindness. Laryngeal lesions produce hoarseness and more serious sequelae. The diagnosis is essentially a clinical one; however, skin-smears, histological features and the lepromin skin-test help to con?rm the diagnosis and enable the form of disease to be graded.
Although the World Health Organisation had originally hoped to eliminate leprosy worldwide by 2000, that has proved an unrealistic target. The reason is an absence of basic information. Doctors are unable to diagnose the disorder before a patient starts to show symptoms; meanwhile he or she may have already passed on the infection. Doctors do not know exactly how transmission occurs or how it infects humans – nor do they know at what point a carrier of the bacterium may infect others. The incidence of new infections is still more than 650,000 cases a year or about 4.5 cases per 10,000 people in those countries worst affected by the disease.
Treatment Introduction of the sulphone compound, dapsone, revolutionised management of the disease. More recently, rifampicin and clofazimine have been added as ?rst-line drugs for treatment. Second-line drugs include minocycline, o?oxacin and clarithromycin; a number of regimens incorporating several of these compounds (multi-drug regimens – introduced in 1982) are now widely used. A three-drug regime is recommended for multi-bacillary leprosy and a two-drug one for parcibacillary leprosy. Dapsone resistance is a major problem worldwide, but occurs less commonly when multi-drug regimens are used. Older compounds – ethionamide and prothionamide
– are no longer used because they are severely toxic to the liver. Corticosteroids are sometimes required in patients with ‘reversal reaction’. Supportive therapy includes physiotherapy; both plastic and orthopaedic surgery may be necessary in advanced stages of the disease. Improvement in socio-economic conditions, and widespread use of BCG vaccination are of value as preventive strategies. Early diagnosis and prompt institution of chemotherapy should prevent long-term complications.... leprosy
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.... hansen’s disease