Abstract: Objective: To investigate the clinical characteristics and related factors of patients with leprosy reactions during multidrug therapy (MDT), and to provide basis for leprosy prevention and treatment. Methods: Relevant information of leprosy patients registered in the LEPMIS in Shandong Province who completed MDT and suffered from leprosy reactions from 2006 to 2020, were collected. General descriptive and Spearman’s correlation statistical analysis were used to evaluate the characteristics of leprosy reaction and its correlation with relevant factors in SPSS 23.0. Results: 314 patients completed MDT from 2006 to 2020, of whom 43 had leprosy reaction (13.7%), including 39 (90.7%) new cases and 4 (9.3%) relapsed cases, 3 BT (7.0%), 14 BL (32.5%), and 26 LL (60.5%). A total of 69 times leprosy reaction occurred in 43 patients during MDT, with an average of 1.6 times per case, 15(34.9%) patients suffered from at least twice of reaction. Of 40 cases, type 1 reaction occurred in 9 (20.9%),  type 2 reaction occurred in 27（62.8%）and two types of reactions both occurred in 3 cases (7.0%). The first time reaction occurred during the first 8 months of MDT in 26 cases (60.4%). Spearman analysis showed that the times of leprosy reactions during MDT was positively correlated with education level (rs=0.383, P=0.011) and negatively correlated with the time of confirmed diagnosis (rs=-0.323, P=0.035).  Conclusion: The incidence of leprosy reactions in patients with leprosy during MDT is high. Leprosy reactions are more common in LL patients and can occur repeatedly. Type 2 reaction is more common than type 1 reaction in MDT patients, which mostly occurs within the first 8 months of MDT. The times of reaction is related to education level and confirmed time of diagnosis. 

Key words: leprosy, leprosy reactions, multidrug therapy