All of the following are characteristic features of tuberculoid leprosy EXCEPT:

Explanation

## Classification of Leprosy: Tuberculoid vs Lepromatous ### Tuberculoid Leprosy (TT) — Key Features **Key Point:** Tuberculoid leprosy represents the immunologically competent end of the leprosy spectrum, characterized by strong cell-mediated immunity and minimal bacillary burden. | Feature | Tuberculoid | Lepromatous | |---------|------------|-------------| | **Lesions** | Few, well-demarcated, hypopigmented macules | Numerous, ill-defined erythematous plaques | | **Bacillary load** | Paucibacillary (1–5 bacilli) | Multibacillary (>100 bacilli) | | **Lepromin test** | Positive (strong CMI) | Negative (weak CMI) | | **Nerve involvement** | Early, severe (asymmetric) | Late, mild (symmetric) | | **Disability risk** | High (due to early nerve damage) | Low initially, high if untreated | ### Why Option 4 Is Wrong **High-Yield:** "Numerous ill-defined erythematous plaques with high bacillary load" is a **lepromatous leprosy** feature, NOT tuberculoid. This is the key discriminator in all leprosy classification questions. ### Clinical Pearl **Mnemonic: TB (Tuberculoid) = Few & Fierce** - Few lesions - Few bacilli (paucibacillary) - Fierce immunity (positive lepromin) - Fierce nerve damage (early, asymmetric) Conversely, **Lepromatous = Many & Meek** - Many lesions - Many bacilli (multibacillary) - Meek immunity (negative lepromin) ### Lepromin Test (Mitsuda Test) **Key Point:** The lepromin test measures delayed-type hypersensitivity (Type IV) to *Mycobacterium leprae* antigens. It is **positive in tuberculoid** and **negative in lepromatous** leprosy. [cite:Park 26e Ch 10]