Leprosy reactions are acute inflammatory processes, immunologically mediated that may be precipitated by many factors, including infections and vaccines. They classified in Type 1 Reaction or Reversal Reaction, 2 (T2LR). The most common clinical manifestation of T2LR is the erythema nodosum (EN), and, because this, it also called Erythema Nodosum Leprosum (ENL). Reactions can occur before, duri...