In a 16‑month‑old female weighing 9.2 kg who presents to the emergency department with an infected cat‑scratch wound, what is the appropriate treatment?

Treatment of Infected Cat Scratch in a 16-Month-Old

Treat this infected cat scratch with oral amoxicillin-clavulanate at 45 mg/kg/day divided twice daily (approximately 200 mg twice daily for this 9.2 kg child), along with proper wound care including copious irrigation and debridement if needed. 1

Antibiotic Selection

The IDSA guidelines clearly recommend amoxicillin-clavulanate as first-line therapy for animal bite wounds because it provides coverage against both aerobic and anaerobic bacteria commonly found in cat-related wounds 1. This is critical because:

• Pasteurella multocida is isolated in over 50% of cat bite/scratch wounds and can cause serious infection with severe complications 2
• Cat wounds carry polymicrobial flora including Staphylococcus, Streptococcus, and anaerobes 1, 3
• Cat scratches/bites to the hand have the highest infection risk 2

Dosing for This Patient

For a 9.2 kg child:

• Amoxicillin-clavulanate: 45 mg/kg/day divided BID = approximately 200 mg (of amoxicillin component) twice daily
• Use the 400 mg/57 mg per 5 mL suspension formulation
• Duration: 5-7 days for mild infections, longer if severe

Alternative Options

If penicillin allergy exists:

• TMP-SMX at 5-10 mg/kg/day of TMP component divided BID 1 - though this has poor anaerobic coverage
• Consider adding metronidazole for anaerobic coverage if using TMP-SMX 1

Note: Fluoroquinolones (ciprofloxacin, levofloxacin) are contraindicated in this age group due to cartilage toxicity concerns, despite being listed in adult guidelines 1.

Wound Management

Beyond antibiotics, proper wound care is essential:

• Copious irrigation with normal saline using a 20-mL or larger syringe 4
• Explore the wound for depth, foreign bodies, and involvement of tendons or bone 1
• Do NOT primarily close cat scratch/bite wounds except facial wounds (for cosmetic reasons) - these require cautious debridement and preemptive antibiotics 1
• Cat wounds are typically puncture-type injuries with high infection risk

Tetanus Prophylaxis

Verify tetanus immunization status 1:

• At 16 months, this child should have received 3 doses of DTaP (at 2,4, and 6 months)
• If incomplete series or uncertain, administer DTaP
• If complete primary series, no booster needed (next due at 4-6 years)

Critical Pitfalls to Avoid

1. Don't use first-generation cephalosporins or clindamycin alone - they miss Pasteurella multocida, which is highly prevalent in cat wounds 1
2. Don't underestimate cat scratches - they penetrate deeply and have higher infection rates than dog bites 2
3. Watch for systemic cat scratch disease (Bartonella henselae) - if fever, lymphadenopathy, or systemic symptoms develop beyond local wound infection, consider azithromycin 10 mg/kg day 1, then 5 mg/kg days 2-5 5, 6
4. Hand wounds require aggressive treatment - these have the highest complication rates 1, 2

When to Escalate Care

Admit for IV antibiotics (ampicillin-sulbactam 150 mg/kg/day divided q6h) if:

• Signs of deep tissue infection, abscess, or sepsis
• Involvement of joints, tendons, or bone
• Immunocompromised state
• Failed outpatient therapy after 48-72 hours

Follow-Up

Reassess in 24-48 hours to ensure clinical improvement. Lack of improvement warrants wound culture and consideration of resistant organisms or deeper infection 1.