Cephalexin Dosing for Pediatric Mild Burns with Localized Infection
For a child with a mild superficial burn and localized bacterial infection, use oral cephalexin at 25-50 mg/kg/day divided into 3-4 doses (or alternatively 25-50 mg/kg/day divided into 2 doses every 12 hours for skin and soft tissue infections). This dosing is based on the IDSA 2014 guidelines for skin and soft tissue infections 1.
Specific Dosing Recommendations
The FDA-approved dosing for pediatric skin and soft tissue infections allows flexibility 2:
- Standard dosing: 25-50 mg/kg/day divided every 6 hours (four times daily)
- Alternative dosing: For skin infections specifically, the total daily dose may be divided and given every 12 hours (twice daily)
Practical Weight-Based Dosing Examples
For four times daily dosing using 125 mg/5 mL suspension 2:
- 10 kg child: 1/2 to 1 teaspoon four times daily
- 20 kg child: 1 to 2 teaspoons four times daily
- 40 kg child: 2 to 4 teaspoons four times daily
For twice daily dosing using 125 mg/5 mL suspension 2:
- 10 kg child: 1 to 2 teaspoons twice daily
- 20 kg child: 2 to 4 teaspoons twice daily
- 40 kg child: 4 to 8 teaspoons twice daily
Evidence-Based Considerations
The IDSA guidelines specifically list cephalexin as appropriate for impetigo and skin/soft tissue infections caused by Staphylococcus and Streptococcus species 1. For mild burns with localized infection, this represents the most appropriate first-line oral therapy assuming methicillin-susceptible organisms.
Recent pharmacokinetic data supports less frequent dosing regimens. A 2022 study demonstrated 89.7% success rates using high-dose oral cephalexin for moderate cellulitis in children 3. Additionally, 2020 pharmacokinetic modeling showed that twice-daily dosing at 22-45 mg/kg can achieve adequate drug levels for MSSA with MICs of 1-2 mg/L 4.
Duration and Monitoring
- Treatment duration: Typically 7-10 days for skin and soft tissue infections 1
- Severe infections: May require doubling the dose 2
- Follow-up: Monitor for clinical improvement within 48-72 hours; if worsening or no improvement, consider MRSA coverage or alternative diagnosis
Important Caveats
⚠️ MRSA consideration: If the child has risk factors for MRSA (previous MRSA infection, recent hospitalization, failed initial therapy), cephalexin will be inadequate. In such cases, clindamycin (20 mg/kg/day in 3 divided doses orally) or trimethoprim-sulfamethoxazole would be more appropriate 1.
⚠️ Adherence: The twice-daily dosing regimen significantly improves medication adherence compared to four-times-daily dosing, which is particularly important in outpatient pediatric management 3, 4.
⚠️ Burn-specific concerns: While the evidence provided focuses on general skin infections, mild superficial burns with localized infection follow similar antimicrobial principles. However, if there are signs of systemic infection (fever, tachycardia, extensive involvement), parenteral therapy should be considered 1.