What is the recommended cefaclor dosage and treatment duration for a child aged ≥1 month with a skin or skin‑structure infection caused by susceptible organisms such as methicillin‑susceptible Staphylococcus aureus or Streptococcus pyogenes?

Cefaclor Dosing for Pediatric Skin Infections

For skin and soft tissue infections in children ≥1 month caused by susceptible organisms (methicillin-susceptible Staphylococcus aureus or Streptococcus pyogenes), cefaclor is NOT the preferred first-line agent; instead, use cephalexin 25 mg/kg/day divided into 4 doses or amoxicillin-clavulanate for broader coverage. 1

Why Cefaclor Is Not First-Line

While cefaclor has demonstrated efficacy in pediatric skin infections, current guidelines prioritize other agents:

• First-generation cephalosporins (cephalexin) are preferred for uncomplicated MSSA skin infections at 25 mg/kg/day in 4 divided doses 1
• Amoxicillin-clavulanate offers superior coverage against both S. aureus and S. pyogenes, making it the oral antibiotic of choice for most uncomplicated superficial skin infections requiring systemic therapy 2
• Cefaclor showed inferior bacteriological efficacy compared to cefprozil in comparative trials, despite similar clinical efficacy 3

If Cefaclor Must Be Used

When cefaclor is selected (typically as an alternative when first-line agents cannot be used):

• Standard dosing: 20-40 mg/kg/day divided into 2-3 doses 4, 3
• Duration: 7 days is typically sufficient, though most clinical trials used 10 days 5
• Maximum daily dose: Should not exceed adult dosing equivalents 3

Preferred Treatment Algorithm for Pediatric Skin Infections

For Mild-to-Moderate Infections (Outpatient)

MSSA suspected or confirmed:

• Cephalexin 25 mg/kg/day in 4 divided doses (first choice) 1
• Dicloxacillin 25 mg/kg/day in 4 divided doses (equally effective alternative) 1
• Amoxicillin-clavulanate provides broader coverage including anaerobes 2

Community-acquired MRSA suspected:

• Clindamycin 10-20 mg/kg/day in 3 divided doses if local resistance <10% 1, 6
• TMP-SMX 8-12 mg/kg/day (based on trimethoprim) in 2 divided doses as alternative 1, 6
• Do NOT use TMP-SMX as monotherapy for cellulitis due to poor streptococcal coverage 6

For Moderate-to-Severe Infections (Hospitalization Required)

MSSA infections:

• Nafcillin 50 mg/kg/dose IV every 4-6 hours (preferred) 1
• Cefazolin 33 mg/kg/dose IV every 8 hours if non-type 1 penicillin allergy 1, 6

MRSA suspected or confirmed:

• Vancomycin 15 mg/kg/dose IV every 6 hours (40 mg/kg/day total) 1, 7
• Add clindamycin 10-13 mg/kg/dose IV every 6-8 hours for toxin-mediated syndromes to suppress exotoxin production 7, 1

Critical Treatment Duration

• Standard duration: 7 days for uncomplicated skin infections 6
• Extend therapy beyond 5-7 days if infection has not improved 6
• SSSS and severe infections: 7-14 days guided by clinical response 7

Important Caveats and Pitfalls

Age-related contraindications:

• Never use tetracyclines (doxycycline, minocycline) in children <8 years due to tooth discoloration risk 7, 1, 6

Resistance considerations:

• Verify clindamycin susceptibility before use, as inducible resistance is common in MRSA 7
• Macrolide resistance in S. pyogenes is increasing, making cephalosporins more reliable 4

Special situations requiring broader coverage:

• Animal/human bites: Use amoxicillin-clavulanate for polymicrobial coverage including anaerobes 6
• Immunocompromised patients: Consider broader gram-negative and anaerobic coverage 6

Topical therapy for localized disease:

• Mupirocin 2% ointment for limited impetigo and minor infections 7, 1, 2
• Avoid systemic antibiotics for purely localized furunculosis treatable with incision and drainage 6