Leprosy type 1 (reversal) reactions and their management

The type of leprosy that affects an individual depends on the immune response mounted against the organism. This leads to a spectrum of disease which may be complicated by immunological phenomena called reactions. Antimicrobial chemotherapy is effective in treating the Mycobacterium leprae infection but up to 30% of individuals with borderline disease experience Type 1 reactions (T1Rs). T1Rs are immunologically mediated episodes, localised in skin and nerves, which are a major cause of nerve function impairment. Nerve function impairment may result in disability and deformity. We review the frequency and features of Type 1 reactions. The data from the limited number of randomised controlled trials of treatment are discussed. These four randomised controlled trials were all conducted in south Asia. The accepted treatment of T1Rs is with oral corticosteroids but there is no consensus about the dose or duration of treatment due to the lack of data. One randomised controlled trial showed that patients treated with a 5 month course of prednisolone (total dose 2.31 g) were less likely to need additional prednisolone than those treated with a 3 month course of prednisolone (total dose 2.94 g). This study did not use nerve function as an outcome measure. The improvement in nerve function impairment with steroid treatment is highly variable, with 33-73% of nerves recovering fully. Optimal steroid regimes and alternative treatments need to be identified if the disability associated with leprosy is to be minimised. Search strategy Papers for this review were identified by repeated searches of the Cochrane Clinical Trials Register, PubMed and LILACS with various combinations of the following search terms 'leprosy', 'lepra', 'reaction', 'steroids', 'corticosteroids', 'reversal', 'Type 1', 'Hansen*'. Searches were complete to the end of November 2008.