A 42-year-old woman from Odisha presents with multiple ill-defined hypopigmented macules and plaques on her trunk and limbs with loss of sensation. Slit-skin smear shows 4+ acid-fast bacilli. Nerve thickening is present. She is classified as having lepromatous leprosy. What is the drug of choice for her treatment?

## Lepromatous Leprosy: Classification & MDT Regimen ### Disease Characteristics Lepromatous leprosy (LL) is the most severe form of Hansen's disease: - **Bacillary load:** Very high (4–6+ on slit-skin smear) - **Skin lesions:** Numerous ill-defined macules, plaques, nodules; symmetrical distribution - **Nerve involvement:** Early and extensive nerve thickening - **Immune response:** Absent (Th2-dominant, poor cell-mediated immunity) - **Infectivity:** Highly contagious ### WHO MDT Regimen for Lepromatous Leprosy **Key Point:** Lepromatous leprosy is treated with **multidrug therapy (MDT) for 12 months** (not 6 months), consisting of: - **Rifampicin** 600 mg once monthly (supervised) - **Dapsone** 100 mg daily (unsupervised) - **Clofazimine** 50 mg daily (unsupervised) - **Duration:** 12 months **High-Yield:** The 12-month duration for lepromatous leprosy (vs. 6 months for paucibacillary forms) is critical to prevent relapse and ensure bacteriological cure. Relapse rates are ~5% at 5 years if treatment is inadequate. ### Comparison: Paucibacillary vs. Lepromatous MDT | Parameter | Paucibacillary (TT, BT, I) | Lepromatous (LL, BL) | |-----------|---------------------------|----------------------| | **Bacillary load** | 0–5+ | 4–6+ | | **MDT regimen** | Rifampicin + Dapsone + Clofazimine | Rifampicin + Dapsone + Clofazimine | | **Duration** | 6 months | 12 months | | **Relapse rate** | <1% | ~5% (if inadequately treated) | | **Nerve involvement** | Late, limited | Early, extensive | ### Mechanism of Action in LL 1. **Rifampicin:** Bactericidal; rapidly kills bacilli; reduces infectivity within 2 weeks 2. **Dapsone:** Bacteriostatic; prevents resistance; synergistic with rifampicin 3. **Clofazimine:** Bacteriostatic; anti-inflammatory; prevents erythema nodosum leprosum (ENL); slow onset (4–6 weeks) **Clinical Pearl:** Clofazimine is especially important in lepromatous leprosy because it reduces the incidence of erythema nodosum leprosum (ENL), a severe immune complex-mediated reaction that occurs in ~50% of LL patients during or after treatment. **Mnemonic:** **RDC-12** = Rifampicin, Dapsone, Clofazimine for 12 months (lepromatous/multibacillary leprosy). [cite:Park 26e Ch 8; WHO Guidelines for Leprosy]