A 35-year-old farmer from rural Maharashtra presents with a single hypopigmented macule on his left forearm with loss of sensation. Slit-skin smear examination shows 0 bacilli per 100 fields. Lepromin test is strongly positive. What is the most appropriate next step in management?

Explanation

## Clinical Classification and Management Rationale **Key Point:** This patient has **Indeterminate Leprosy** progressing toward **Tuberculoid Leprosy** (TT), based on: - Single lesion with clear sensory loss - Negative slit-skin smear (0 bacilli) - Strongly positive lepromin test (indicates good cell-mediated immunity) ### Why Nerve Assessment Before MDT? **High-Yield:** Baseline nerve function assessment (monofilament testing, grip strength, intrinsic muscle testing) is **mandatory before initiating MDT** in all leprosy patients, especially in tuberculoid forms where: 1. Nerves are already inflamed and at risk of dysfunction 2. Early detection of subclinical nerve involvement guides steroid prophylaxis decisions 3. Establishes baseline to monitor for lepra reactions during treatment ### Classification and Treatment Duration | Feature | Tuberculoid (TT) | Borderline Tuberculoid (BT) | Indeterminate | |---------|------------------|---------------------------|---------------| | Lesions | 1–5, well-defined | Few to moderate | Usually 1 | | Sensory loss | Marked | Marked | Present | | Bacillary load | 0–1 per field | 1–10 per field | 0–1 per field | | Lepromin test | Strongly positive | Positive | Variable/positive | | MDT duration | 6 months (PB) | 12 months (MB) | 6 months (PB) | **Clinical Pearl:** This patient fits **Paucibacillary (PB) leprosy** criteria and requires **6-month MDT**, but nerve assessment must precede treatment initiation. ### Management Algorithm ```mermaid flowchart TD A[Single lesion + sensory loss]:::outcome --> B{Slit-skin smear?}:::decision B -->|Negative/1 bacillus| C[PB Leprosy]:::outcome C --> D[Baseline nerve function assessment]:::action D --> E[Start MDT: Rifampicin + Dapsone for 6 months]:::action E --> F[Monitor for lepra reactions]:::action B -->|>1 bacillus| G[MB Leprosy]:::outcome G --> H[12-month MDT]:::action ``` **Mnemonic:** **PB-6, MB-12** — Paucibacillary = 6 months, Multibacillary = 12 months MDT.