A 6-year-old girl from Delhi presents with her father reporting a 5-day history of painful pustules on her right forearm and hand. The lesions began as small red papules that progressed to pustules with surrounding erythema and edema. The child had a minor abrasion from a playground fall 2 days before the rash appeared. On examination, she has multiple pustules with purulent drainage, some coalescing into larger lesions. The regional lymph nodes (epitrochlear and axillary) are enlarged and tender. There is no systemic fever or constitutional symptoms. A culture from the pustule grows methicillin-sensitive *Staphylococcus aureus* (MSSA). The child's mother reports that the girl had a similar episode 6 months ago that resolved with oral antibiotics. What is the most appropriate management to prevent recurrence?

Explanation

## Diagnosis: Recurrent Staphylococcal Pyoderma (Non-Bullous Impetigo with Regional Lymphadenitis) **Key Point:** This is a case of **recurrent impetigo** caused by MSSA with regional lymphadenopathy. The history of a similar episode 6 months ago indicates either inadequate treatment, poor compliance, or persistent nasal carriage of *S. aureus*. **High-Yield:** Recurrent staphylococcal skin infections in immunocompetent children are often due to: 1. **Nasal carriage** of *S. aureus* (20–30% of population; up to 80% in patients with recurrent infections) 2. **Inadequate initial treatment** or poor compliance 3. **Poor hygiene** or contaminated fomites 4. **Unrecognized underlying immunodeficiency** (rare in this case, given clinical stability) ### Management Algorithm for Recurrent Impetigo ```mermaid flowchart TD A[Recurrent Impetigo]:::outcome --> B{Systemic symptoms?}:::decision B -->|Yes| C[Systemic antibiotic]:::action B -->|No| D[Localized disease?]:::decision C --> E[Oral cephalexin 7 days]:::action D -->|Yes| F[Topical mupirocin]:::action D -->|No| E E --> G[Eradicate nasal carriage]:::action F --> G G --> H[Intranasal mupirocin 5 days]:::action H --> I[Hygiene counseling]:::action I --> J[Prevent recurrence]:::outcome ``` **Clinical Pearl:** The **regional lymphadenitis** (epitrochlear and axillary nodes) indicates secondary bacterial lymphangitis, confirming systemic spread beyond simple localized impetigo. This warrants systemic antibiotic therapy. ### Rationale for Correct Answer **Oral cephalexin for 7 days + intranasal mupirocin for 5 days** is the gold-standard approach: | Step | Rationale | |------|----------| | **Oral cephalexin 25–50 mg/kg/day × 7 days** | Treats active infection; excellent MSSA coverage; good skin penetration | | **Intranasal mupirocin 2% ointment BID × 5 days** | Eradicates nasal carriage (the source of recurrence); applied to anterior nares | | **Hygiene counseling** | Prevent reinfection: avoid sharing towels, nail clippers, razors; keep lesions covered | **Mnemonic:** **CARE** — *C*ephalexin, *A*ntibiotics, *R*ecurrence prevention, *E*radicate nasal carriage. ### Why Nasal Carriage Eradication? **Key Point:** *S. aureus* colonizes the anterior nares in 20–30% of healthy individuals. In patients with recurrent skin infections, this rate approaches 80%. Without eradication, the patient will remain at risk for reinfection. - **Mupirocin** is the gold standard for nasal carriage eradication - Applied to anterior nares (not systemic) - 5-day course achieves 90% eradication - Safe and well-tolerated in children [cite:Robbins 10e Ch 25; Park 26e Ch 8]