Bacterial Skin Infections — MCQs

Q: A 35-year-old woman presents with hypopigmented and anesthetic patches on her arms, and a positive skin smear for acid-fast bacilli. What is the most likely diagnosis?

Leprosy. ***Leprosy*** - The presence of **hypopigmented and anesthetic patches** is pathognomonic for leprosy, indicating nerve involvement - A **positive skin smear for acid-fast bacilli** directly confirms the presence of *Mycobacterium leprae*, the causative agent - This combination of anesthesia with skin lesions and AFB positivity is diagnostic *Psoriasis* - Psoriasis presents with **red, scaly plaques** with well-demarcated borders, typically on extensor surfaces - Does not cause **anesthesia** and is not associated with acid-fast bacilli - Auspitz sign may be present (pinpoint bleeding on scale removal) *Vitiligo* - Causes **complete depigmentation (white patches)** due to melanocyte destruction, not hypopigmentation - Patches are **not anesthetic** - sensation remains intact - An **autoimmune condition** with no involvement of acid-fast bacilli *Pityriasis versicolor* - A **superficial fungal infection** (Malassezia species) causing hypo- or hyperpigmented patches with fine scaling - Patches are **not anesthetic** and maintain normal sensation - **Skin smear shows yeast and hyphae** ("spaghetti and meatballs" appearance), not acid-fast bacilli

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Impetigo

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Folliculitis, Furuncles, and Carbuncles

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Ecthyma

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Erysipelas and Cellulitis

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Staphylococcal Scalded Skin Syndrome

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Necrotizing Fasciitis

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Cutaneous Tuberculosis

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Leprosy

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Lyme Disease

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Syphilis

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Antibiotic Resistance in Dermatology

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Prophylaxis and Management

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