A 42-year-old woman with borderline tuberculoid leprosy develops acute inflammation of existing lesions with pain and swelling 2 months into MDT. Histology shows epithelioid cell granulomas with few bacilli. Which drug is the preferred treatment for this lepra reaction?

Explanation

## Lepra Reaction Type 1 (Reversal Reaction) ### Clinical Presentation This patient has **Type 1 lepra reaction (reversal reaction)**, a delayed-type hypersensitivity (Type IV) reaction occurring in borderline forms of leprosy (BT, BL, BB). **Key Point:** Reversal reaction presents with acute inflammation of existing lesions, pain, swelling, and nerve involvement. Histologically shows epithelioid granulomas with few bacilli—indicating immune upregulation. ### Drug of Choice: Prednisolone | Feature | Type 1 Reaction (Reversal) | Type 2 Reaction (ENL) | |---------|---------------------------|----------------------| | **Immunology** | Type IV hypersensitivity | Type III hypersensitivity | | **Bacillary load** | Few bacilli | Many bacilli | | **Timing** | During or after MDT | During or after MDT | | **Lesions affected** | Existing lesions inflame | New tender nodules | | **Drug of choice** | **Prednisolone** | **Prednisolone** (first-line) | | **Dose** | 0.5–1 mg/kg/day | 0.5–1 mg/kg/day | | **Alternative** | NSAIDs (mild cases) | Thalidomide (resistant) | ### Prednisolone Dosing in Type 1 Reaction 1. **Initiation:** 0.5–1 mg/kg/day (typically 40–80 mg/day) 2. **Duration:** Continue until inflammation resolves (4–12 weeks) 3. **Taper:** Reduce by 5–10 mg every 1–2 weeks 4. **Monitoring:** Assess lesions and nerve function monthly **High-Yield:** Prednisolone is the first-line agent for BOTH Type 1 and Type 2 reactions. The distinction lies in the underlying immunology, not the treatment. ### Differential: Type 1 vs Type 2 Lepra Reactions ```mermaid flowchart TD A[Lepra Reaction]:::outcome --> B{Leprosy type?}:::decision B -->|BT, BL, BB| C[Type 1 Reaction]:::outcome B -->|LL, BL| D[Type 2 Reaction]:::outcome C --> E[Existing lesions inflame]:::outcome C --> F[Few bacilli on histology]:::outcome D --> G[New tender nodules]:::outcome D --> H[Many bacilli on histology]:::outcome E --> I[Prednisolone 0.5-1 mg/kg/day]:::action G --> I ``` **Clinical Pearl:** Type 1 reactions indicate immune reconstitution—a favorable prognostic sign. Prednisolone prevents nerve damage and tissue destruction by suppressing the exaggerated cell-mediated response. **Warning:** Do not use thalidomide for Type 1 reactions; it is specifically for ENL (Type 2). Confusing the two is a common exam trap.