## First-Line Treatment of Non-Bullous Impetigo **Key Point:** For non-bullous impetigo with localized lesions, **topical mupirocin 2%** is the drug of choice per current international and Indian guidelines (IADVL, AAD, IDSA). ### Topical vs Systemic Therapy in Impetigo | Feature | Topical (First-line) | Systemic (Reserved for) | |---------|----------------------|-------------------------| | **Indication** | Localized lesions, limited body sites | Widespread disease (>2% BSA), bullous impetigo, systemic signs, immunocompromised | | **Drug of choice** | Mupirocin 2% TID × 5–7 days | Oral cephalexin or amoxicillin-clavulanate | | **Advantage** | High local concentration, minimal systemic side effects | Broader coverage for extensive disease | **High-Yield:** The stem describes a child with honey-crusted lesions on the face and exposed areas — this is classic **non-bullous impetigo** (the most common form, ~70% of cases). In the absence of explicit indicators of widespread disease (>2% BSA, systemic signs, or failed topical therapy), **topical mupirocin** is the standard first-line treatment. ### Why Topical Mupirocin? 1. **Mechanism:** Inhibits bacterial isoleucyl-tRNA synthetase → bactericidal against S. aureus and S. pyogenes. 2. **Efficacy:** Clinical cure rates of 90–95% for localized non-bullous impetigo, comparable to oral antibiotics. 3. **Guideline support:** Recommended as first-line by AAD, IADVL, and WHO for localized impetigo. 4. **Resistance avoidance:** Topical use minimizes systemic antibiotic resistance pressure. 5. **Safety:** Negligible systemic absorption; safe in children. ### Why Not the Other Options? - **Oral amoxicillin-clavulanate (A):** Reserved for widespread or recurrent impetigo, or when topical therapy fails. Not first-line for localized disease. - **IV cefazolin (C):** Used only for severe skin and soft-tissue infections requiring hospitalization; not appropriate here. - **Oral clindamycin (D):** An alternative for MRSA-associated or penicillin-allergic cases; not first-line for routine non-bullous impetigo. **Clinical Pearl:** Topical mupirocin is preferred over topical fusidic acid in areas with high fusidic acid resistance. For truly widespread impetigo (multiple sites, >2% BSA), oral cephalexin or amoxicillin-clavulanate is added. **Mnemonic:** **"MUP for localized impetigo"** — **MU**pirocin is the **P**rimary topical choice. [cite: Rook's Textbook of Dermatology 9e; KD Tripathi Essentials of Medical Pharmacology 8e; IADVL Guidelines for Impetigo]
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.