Paper I
Question
Differences between tuberculoid and lepromatous leprosy
Answer
| Feature | Tuberculoid leprosy | Lepromatous leprosy |
|---|---|---|
| Host immunity | Strong cell-mediated immunity (Th1 response) | Poor cell-mediated immunity |
| Bacillary load | Paucibacillary (few/no bacilli); lepromin test positive | Multibacillary (numerous bacilli); lepromin test negative |
| Skin lesions | Few, well-defined, asymmetric, hypopigmented/anaesthetic patches | Numerous, ill-defined, symmetric, diffuse infiltration |
| Nerve involvement | Early, marked, asymmetric nerve thickening | Late, symmetric, diffuse nerve involvement |
| Granuloma | Epithelioid cell granulomas with Langhans giant cells | Sheets of foamy macrophages (lepra/Virchow cells) laden with bacilli |
| Other organ involvement | Usually spared | Common (nasal septum destruction, “leonine facies”, testicular atrophy) |
| Prognosis | Stable, self-limiting | Progressive, more destructive if untreated |
| Type of hypersensitivity | Type IV (delayed-type) | Absent/weak cell-mediated response |