Clinical course of erythema nodosum leprosum: an 11-year cohort study in Hyderabad, India.

Erythema nodosum leprosum (ENL) or type 2 lepra reactions complicate lepromatous leprosy and borderline lepromatous leprosy. We report an 11-year retrospective case record analysis of 481 outpatients with borderline lepromatous and lepromatous leprosy at the Dhoolpet Leprosy Research Center in Hyderabad, India.. The overall prevalence of ENL was 24%, 49.4% among cases of lepromatous leprosy (LL) and 9% among cases of borderline lepromatous (BL) leprosy. Logistic regression analysis identified LL (odds ratio [OR] = 8.4, 95% confidence interval [CI] = 4.6-15.4, P < 0.001) and BL with a bacterial index > or = 4+ (OR = 5.2, 95% CI = 2.1-12.9, P = 0.001) as major risk factors. The average patient with ENL was male, 34.7 years of age, and had multiple episodes of ENL (mean = 3.1) over an 18.5-month period. Three types of ENL were identified: single acute ENL, multiple acute ENL (repeated discrete episodes), and chronic ENL (continuous episodes). Acute single ENL is rare, accounting for only 8% of cases. Chronic ENL accounted for 62.5% of the cohort. Chronic ENL was of longer duration and more severe. An age > or = 35 years was a risk factor for developing chronic ENL. Patients with chronic ENL were more compliant with multi-drug therapy, especially during the first six doses of multi-drug therapy. Distinguishing these different types of ENL would be useful for patient management and developing improved treatment of these debilitating reactions. Improved strategies for treatment and management of these reactions need to be developed.