What is the recommended dose of cephalexin (cephalexin) for a child with a skin infection?

Cephalexin Dosing for Pediatric Skin Infections

For children with skin infections, cephalexin should be dosed at 25-50 mg/kg/day divided into 3-4 doses per day (typically 25 mg/kg/day in 4 divided doses). 1

Recommended Dosing Regimen

Based on the most recent guidelines from the Infectious Diseases Society of America:

• Standard dosing: 25 mg/kg/day divided into 4 doses 1
• Dose range: 25-50 mg/kg/day 1
• Duration: 7-10 days, depending on clinical response 1

For skin infections specifically caused by Staphylococcus aureus (MSSA):

• Oral cephalexin: 25-50 mg/kg/day in 4 divided doses 1
• Maximum dose: 500 mg per dose 1

Alternative Dosing Options

Recent research suggests that less frequent dosing may be effective while improving adherence:

• Three times daily option: 45 mg/kg/dose (maximum 1.5 g) three times daily 2
• Twice daily option: 22-45 mg/kg twice daily for MSSA with lower MICs (1-2 mg/L) 3

Dosing Considerations

Age-specific considerations:

• Children over 1 year: Follow the standard weight-based dosing above
• Adolescents ≥15 years: May use adult dosing of 250-500 mg every 6 hours 4

Severity considerations:

• Mild infections: Lower end of dosing range (25 mg/kg/day)
• Moderate to severe infections: Higher end of dosing range (50 mg/kg/day) 1
• Severe infections: May require up to 100 mg/kg/day in divided doses 4

Common Pitfalls and Caveats

1. Underdosing: Inadequate dosing may lead to treatment failure and potential development of resistance.

2. Adherence challenges: The standard four-times-daily dosing can be difficult for families to maintain. Consider the three-times-daily regimen (45 mg/kg/dose) if adherence is a concern 2.

3. Penicillin allergy: Cephalexin is a first-generation cephalosporin and should be used with caution in patients with immediate hypersensitivity reactions to penicillin due to potential cross-reactivity 1.

4. Duration of therapy: For streptococcal skin infections, ensure a full 7-10 day course is completed to prevent complications 1.

5. Monitoring: Watch for common side effects including diarrhea, nausea, or rash. Rarely, neutropenia may occur with higher doses 2.

Cephalexin remains a first-line agent for skin infections in children due to its excellent coverage of the most common causative pathogens (Staphylococcus aureus and Streptococcus pyogenes), favorable safety profile, and established efficacy.