Interventions to treat erythema nodosum leprosum, a complication of leprosy

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.

Authors' conclusions: 

There is some evidence of benefit for thalidomide and clofazimine, but generally we did not find clear evidence of benefit for interventions in the management of ENL. However, this does not mean they do not work, because the studies were small and poorly reported. Larger studies using clearly defined participants, outcome measures, and internationally recognised scales are urgently required.

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Background: 

Erythema nodosum leprosum (ENL) is a serious immunological complication of leprosy, causing inflammation of skin, nerves, other organs, and general malaise. Many different therapies exist for ENL, but it is unclear if they work or which therapy is optimal.

Objectives: 

To assess the effects of interventions for erythema nodosum leprosum.

Search strategy: 

We searched the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 1, 2009), MEDLINE (from 2003), EMBASE (from 2005), LILACS and AMED (from inception), CINAHL (from 1981), and databases of ongoing trials, all in March 2009. We checked reference lists of articles and contacted the American Leprosy Missions in Brazil to locate studies.

Selection criteria: 

Randomised controlled trials (RCTs) of interventions for ENL in people with leprosy.

Data collection and analysis: 

Two authors performed study selection, assessed trial quality, and extracted data.

Main results: 

We included 13 studies with a total of 445 participants. The quality of the trials was generally poor and no results could be pooled due to the treatments being so heterogeneous. Treatment with thalidomide showed a significant remission of skin lesions compared to acetylsalicylic acid (aspirin) (RR 2.43; 95% CI 1.28 to 4.59) (1 trial, 92 participants). Clofazimine treatment was superior to prednisolone (more treatment successes; RR 3.67; 95% CI 1.36 to 9.91) (1 trial, 24 participants), and thalidomide (fewer recurrences; RR 0.08; 95% CI 0.01 to 0.56) (1 trial, 72 participants). We did not find any significant benefit for intravenous betamethasone compared to dextrose (1 trial, 10 participants), pentoxifylline compared to thalidomide (1 trial, 44 participants), indomethacin compared to prednisolone, aspirin or chloroquine treatments (2 trials, 80 participants), or levamisole compared to placebo (1 trial, 12 participants). Mild to moderate adverse events were significantly lower in participants taking 100 mg thalidomide compared to 300 mg thalidomide daily (RR 0.46; 95% CI 0.23 to 0.93). Significantly more minor adverse events were reported in participants taking clofazimine compared with prednisolone (RR 1.92; 95% CI 1.10 to 3.35). None of the studies assessed quality of life or economic outcomes.

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