A 42-year-old woman with borderline tuberculoid leprosy on MDT for 6 weeks presents with acute inflammation of existing skin lesions, painful peripheral nerves, and loss of sensation in the feet. Skin lesions show increased induration and erythema. What is the most appropriate immediate management?

Explanation

## Clinical Diagnosis This patient presents with **Type I Lepra Reaction (Reversal Reaction)**, a delayed-type hypersensitivity (Type IV) reaction characterized by: - Acute inflammation of **existing skin lesions** (increased induration, erythema) - **Acute neuritis** with pain and sensory loss - Occurs in borderline forms (BT, BL) of leprosy - Timing: typically within first 6 months of MDT (can occur up to 1 year after completion) **Key Point:** Type I reaction is immunologically distinct from ENL (Type III). It represents a shift toward the tuberculoid pole of immunity and is NOT due to immune complexes. ## Management of Type I Lepra Reaction ### First-Line Approach **High-Yield:** The management principle is **continue MDT + start high-dose systemic corticosteroids immediately** to prevent irreversible nerve damage: 1. **Continue MDT** — essential to control bacilli and prevent relapse 2. **Prednisolone 0.5–1 mg/kg/day** — high-dose systemic steroids (NOT intramuscular) 3. **Taper over 12–16 weeks** — gradual reduction to prevent rebound 4. **Protect affected nerves** — rest, elevation, NSAIDs for pain **Clinical Pearl:** Type I reaction can cause **irreversible nerve damage** within days if untreated. Early, aggressive corticosteroid therapy is crucial to preserve nerve function and prevent disability (claw hand, foot drop, blindness). ### Decision Algorithm ```mermaid flowchart TD A[Acute inflammation of existing lesions + neuritis]:::outcome --> B{Type of reaction?}:::decision B -->|Type I: lesion inflammation + neuritis| C[Continue MDT]:::action B -->|Type III: new nodules + systemic symptoms| D[Continue MDT + thalidomide] C --> E[Start prednisolone 0.5-1 mg/kg/day]:::action E --> F[Taper over 12-16 weeks]:::action F --> G{Nerve function preserved?}:::decision G -->|Yes| H[Complete MDT + steroids]:::action G -->|No| I[Consider nerve decompression]:::action ``` ### Why High-Dose Systemic Steroids Are Essential - **Intramuscular steroids** (option D) are inadequate for Type I reaction; systemic therapy is required - **Timing is critical** — delaying steroids by even 1–2 weeks can result in permanent nerve damage - **Dose matters** — low-dose steroids are ineffective; 0.5–1 mg/kg/day is the standard **Mnemonic: NERVE** — **N**eeds steroids, **E**arly treatment, **R**eversal reaction, **V**ascular inflammation, **E**ssential to prevent disability **Warning:** Do NOT stop MDT. Type I reaction is NOT a sign of treatment failure; it reflects immune reconstitution and is managed by adding steroids, not changing MDT. [cite:Park 26e Ch 8] ## Comparison: Type I vs Type III Lepra Reactions | Feature | Type I (Reversal) | Type III (ENL) | |---------|-------------------|----------------| | **Immune mechanism** | Type IV (delayed) | Type III (immune complex) | | **Leprosy type** | BT, BL | LL, BL | | **Lesion changes** | Inflammation of existing lesions | New painful nodules | | **Neuritis** | Common, acute | Less common | | **Systemic symptoms** | Mild | Prominent (fever, arthralgia) | | **Timing** | During/early after MDT | During/after MDT | | **Treatment** | Corticosteroids | Corticosteroids + thalidomide | | **Urgency** | URGENT (nerve damage) | Urgent (but less time-sensitive) |