Leprosy

Leprosy continues to be an important cause of peripheral neuropathy. The clinical forms of disease reflect the underlying immune response to Mycobacterium leprae, leading to stable polar tuberculoid and lepromatous forms, and immunologically unstable borderline forms. Despite 20 years of effective multi-drug therapy, new cases continue to present. Outside endemic areas, the diagnosis of leprosy is often missed and neuropathic damage becomes irreversible. Patients may present with skin lesions, or signs of peripheral neuropathy or problems secondary to the neuropathy such as ulcers and osteomyelitis. Diagnosis is clinical and depends on identifying skin lesions and thickened nerves. All patients should be given multi-drug therapy, which comprises rifampicin and dapsone, with clofazimine added in multibacillary cases. Relapse rates are low (about 1%). Nerve damage should be sought and treated with corticosteroids if present for less than 6 months. Immune-mediated reactions complicate the borderline types of leprosy and must be recognized and treated promptly with immunosuppression. Patient education is vital to help compliance and management of disabilities. Stigma remains a problem worldwide. The M. leprae genome has recently been sequenced, and this will improve understanding of this non-cultivable organism and the development of new diagnostic tests. BCG vaccine is currently the most effective protection against leprosy.