The efficacy and safety of thalidomide versus azathioprine as steroid-sparing agents in Erythema Nodosum Leprosum (ENL): a randomized controlled trial

Introduction Erythema Nodosum Leprosum (ENL), a multisystemic disease, can significantly impair patients’ quality of life due to its chronic and recurrent course. Systemic corticosteroids and thalidomide are the mainstay of therapy in the management of severe ENL. However, the role of thalidomide as a steroid-sparing agent is limited by its adverse effects and high cost. No interventional trial has evaluated azathioprine’s efficacy in ENL. This study aimed to compare the safety and efficacy of thalidomide versus azathioprine as a steroid-sparing agent in severe ENL. Methodology This assessor-blinded randomized controlled trial was conducted on 48 patients with severe ENL who were randomly allocated to receive either thalidomide or azathioprine with prednisolone. The outcome measures were to compare the proportion of patients achieving remission at the end of 6 months between the groups, cumulative dose of prednisolone, number of ENL flares, side effects, change in Dermatology Life Quality Index (DLQI) from baseline, and correlation between change in ENL International Study Group (ENLIST) Severity Scale (EESS) score and serum IFN-𝛾 level. Results In the azathioprine group, 20/22 participants and in the thalidomide group, 21/22 achieved remission (p = 0.5). The median cumulative dose of steroids received (p = 0.44) and change in DLQI score (p = 0.44) between the two groups were not significantly different. The azathioprine group had more flares (8/22) as compared with the thalidomide group (2/22). There was no statistically significant correlation between EESS score change and serum IFN-𝛾 level change at three months (correlation coefficient −0.24). Conclusion Azathioprine, a steroid-sparing agent, is an effective alternative to thalidomide to control ENL and improve patients’ quality of life without significant adverse effects.