Erythema nodosum leprosum (ENL) is a severe, multi-system complication of leprosy which is difficult to manage. The evidence for effective treatment is limited and defining outcome measures for clinical trials is difficult. There are no validated measures of disease severity and so we wished to develop a clinical severity scale.

Three published scales that had been used in ENL research were applied to patients with ENL at six leprosy referral centres. An analysis of the clinical features associated with ENL severity was performed on data obtained from the ENLIST 1 study. A meeting of experienced leprosy researchers was held to incorporate the findings from the scale testing and data analysis into a clinical severity scale for ENL Results: None of the three scales used were found to be ideal but some features of each were incorporated into a new scale along with novel items felt to be appropriate. A final 16 item scale – the ENLIST ENL Severity Scale was agreed by the meeting participants and detailed notes and definitions developed.

We have developed a new severity measure for ENL which we propose to subject to formal validation.