Leprosy remains a public health issue in poorer parts of the world. In 2007 there were approximately 255,000 new cases reported worldwide. Leprosy (or Hansen's disease) is a chronic infectious disease. The skin and peripheral nerves of people with leprosy contain leprosy bacteria. Leprosy can be cured with a combination of antibiotics. The immune system plays an important role in leprosy and determines if and how the disease will develop. The response of the immune system to the antigens of the leprosy bacteria may cause periods of inflammation in the skin and nerves, called reactions. Reactions are the main cause of acute nerve damage and disability in leprosy and occur in about one third of people with leprosy. One type of reaction is erythema nodosum leprosum (ENL), a serious and often chronic complication of leprosy caused by the immune system. People with ENL have red, painful swellings in the skin and often feel ill due to fever and general malaise. There are several treatments for ENL, including the oral drugs prednisolone, thalidomide, and clofazimine. We undertook a systematic review on this topic as it was not clear which treatments were most beneficial.
Our review included 13 randomised controlled trials involving 445 participants. These trials assessed: betamethasone (1 trial), thalidomide (5 trials), pentoxifylline (1 trial), clofazimine (3 trials), indomethacin (2 trials), and levamisole (1 trial). Generally, the quality of the studies was poor and many were too small to identify important clinical differences even if they existed. Three small trials showed benefit for thalidomide and clofazimine treatment in terms of fewer further reactions, more treatment successes, and less relapses of ENL.
Adverse events were reported in most of the trials, but it was often not possible to compare the occurrence of any adverse events between the experimental group and control group. Most adverse events reported were not too serious, and only a few participants could not complete treatment due to serious adverse events or for other reasons.
Whether the interventions improved the quality of life of participants, was not evaluated in any of the trials.
Although we did not find clear benefits in these series of small, poorly-performed studies, this does not mean that these drugs do not work in the treatment of ENL, only that scientific evidence is insufficient. Future studies should be better designed and use clear definitions and outcomes, including long-term outcomes and quality of life measures.