What antibiotics are recommended for a 3-year-old with an open wound?

Antibiotic Selection for Open Wounds in a 3-Year-Old Child

For a 3-year-old with an open wound, first-line antibiotic therapy should be oral cephalexin (75-100 mg/kg/day divided into 3-4 doses) or oral clindamycin (30-40 mg/kg/day divided into 3-4 doses) to cover methicillin-susceptible Staphylococcus aureus, which causes over 70% of skin and soft tissue infections in children. 1

Primary Treatment Approach

First-Line Oral Antibiotics

• Cephalexin is the preferred oral agent at 75-100 mg/kg/day divided into 3-4 doses for methicillin-susceptible S. aureus skin infections 2
• Oral clindamycin (30-40 mg/kg/day in 3-4 doses) is an equally effective alternative with the same coverage 2
• Flucloxacillin remains the treatment of choice in some regions as a penicillinase-resistant penicillin, though cephalexin offers broader coverage 1

Treatment Duration

• 7-10 days of therapy is appropriate for most skin and soft tissue infections, despite many clinical trials using 10 days 1
• There is no evidence that 10-day courses are more effective than 7-day courses for uncomplicated skin infections 1

When to Consider Alternative Antibiotics

If Methicillin-Resistant S. aureus (MRSA) is Suspected

• Oral clindamycin (30-40 mg/kg/day in 3-4 doses) is first-line for community-acquired MRSA in well-appearing children 2, 1
• Trimethoprim-sulfamethoxazole is an alternative, but children must be observed closely for potentially severe adverse effects 1
• For severe MRSA infections requiring hospitalization, vancomycin (40-60 mg/kg/day every 6-8 hours) is the treatment of choice 2

If Polymicrobial Infection is Suspected

Consider amoxicillin/clavulanate in specific scenarios:

• Bite wounds (human or mammalian) where polymicrobial coverage is needed 1
• Puncture wounds of the foot 1
• Perianal wounds or decubitus ulcers where mixed flora is likely 1
• Dosing: 45 mg/kg/day of amoxicillin component in 3 doses OR 90 mg/kg/day in 2 doses 3

Critical Supportive Management

Beyond antibiotics, wound care is essential:

• Remove any infected foreign bodies from the wound 1
• Surgical drainage is required for walled-off abscesses or collections 1
• Regular wound cleaning plays a vital role in ensuring cure 1

Common Pitfalls to Avoid

• Do not use amoxicillin alone for open wounds, as it lacks adequate staphylococcal coverage due to beta-lactamase production by most S. aureus strains 1
• Avoid macrolides (erythromycin, azithromycin) as monotherapy due to increasing resistance in S. aureus, though they remain cost-effective alternatives in some settings 1
• Do not overlook the need for drainage - antibiotics alone are insufficient for walled-off infections 1

When to Escalate to Parenteral Therapy

If the child requires intravenous therapy due to severity:

• Ceftriaxone (50-75 mg/kg/day once daily) has major advantages for moderate-to-severe skin infections and may be suitable for outpatient treatment 1
• Cefazolin (150 mg/kg/day every 8 hours) or oxacillin (150-200 mg/kg/day every 6-8 hours) for hospitalized patients with methicillin-susceptible S. aureus 2