A 38-year-old man with lepromatous leprosy on MDT for 3 months presents with acute onset of painful nodules, fever, and neuritis. Skin lesions show erythema and edema. What is the drug of choice for managing this lepra reaction?

Explanation

## Lepra Reaction Type and Management ### Classification of Lepra Reactions **Key Point:** Lepra reactions are classified into two types based on immunological mechanism: - **Type 1 (Reversal Reaction):** Delayed-type hypersensitivity; occurs in borderline forms - **Type 2 (Erythema Nodosum Leprosum, ENL):** Immune complex-mediated; occurs in lepromatous and borderline lepromatous leprosy ### Clinical Presentation in This Case The patient's presentation (acute painful nodules, fever, neuritis occurring 3 months into MDT) is characteristic of **Type 2 lepra reaction (ENL)**. This is an immune complex deposition disease triggered by antigens released from dead bacilli during effective chemotherapy. ### Drug of Choice for ENL | Feature | Prednisolone | Thalidomide | Clofazimine | |---------|--------------|-------------|-------------| | **Mechanism** | Immunosuppression; reduces TNF-α | Immunomodulation; anti-TNF-α; teratogenic | Bacteriostatic; slow onset (weeks) | | **Onset** | Rapid (24–48 hours) | Rapid (24–48 hours) | Slow (4–6 weeks) | | **First-line** | Yes, for acute ENL | Yes, for chronic/recurrent ENL | No, adjunctive only | | **Dose** | 0.5–1 mg/kg/day, taper | 100–400 mg/day | 100–300 mg/day | | **Contraindication** | Relative in TB coinfection | Absolute in pregnancy; teratogenic | None major | **High-Yield:** Prednisolone is the first-line drug for acute ENL because it provides rapid anti-inflammatory and immunosuppressive effects. It reduces TNF-α production and suppresses immune complex deposition. ### Treatment Algorithm for ENL ```mermaid flowchart TD A[Type 2 Lepra Reaction<br/>ENL Diagnosed]:::outcome --> B{Severity?}:::decision B -->|Mild/Moderate| C[Prednisolone 0.5-1 mg/kg/day]:::action B -->|Severe/Recurrent| D[Prednisolone + Thalidomide]:::action C --> E[Taper over 12-16 weeks]:::action D --> F[Prednisolone taper;<br/>Thalidomide 100-400 mg/day]:::action E --> G[Clinical improvement]:::outcome F --> G ``` **Clinical Pearl:** ENL can occur before, during, or after MDT completion. Prednisolone should be started at 0.5–1 mg/kg/day and tapered gradually over 12–16 weeks to prevent relapse. **Warning:** Do not confuse Type 1 (reversal reaction) with Type 2 (ENL). Type 1 also responds to prednisolone but occurs in borderline forms and presents with inflammation of existing lesions and nerves without systemic symptoms like fever.