What is the appropriate management for a cat bite wound?

Management of Cat Bite Wounds

Cat bite wounds require immediate treatment with amoxicillin-clavulanate, copious irrigation, and should NOT be closed (except facial wounds), with tetanus prophylaxis if vaccination is not current within 10 years. 1

Why Cat Bites Are High-Risk Injuries

Cat bites carry a substantially higher infection risk than dog bites, with 20-80% of cat bites becoming infected compared to only 3-18% of dog bites. 2 The key reasons include:

• Pasteurella multocida is isolated in over 50% of cat bite wounds and is carried in approximately 90% of cats' oral cavities 2, 3
• Cat teeth create deep puncture wounds that inoculate bacteria into deeper tissues 4
• Hand wounds from cat bites have the greatest risk of infection and can lead to devastating complications including osteomyelitis, septic arthritis, and tenosynovitis 5, 3

First-Line Antibiotic Treatment

Amoxicillin-clavulanate is the antibiotic of choice for all cat bite wounds, whether for prophylaxis or treatment of established infection. 1, 3, 6 This combination provides coverage against:

• Pasteurella multocida (present in ~90% of cats) 2
• Staphylococcus and Streptococcus species 1
• Anaerobic organisms including Fusobacterium, Prevotella, and Porphyromonas 1

Alternative Antibiotics for Penicillin Allergy

If the patient has a β-lactam allergy, use one of these regimens: 1

• Fluoroquinolone (ciprofloxacin or levofloxacin) PLUS metronidazole for anaerobic coverage
• Moxifloxacin alone (covers both aerobes and anaerobes as monotherapy)
• Doxycycline 100 mg twice daily has excellent activity against Pasteurella multocida 7

Antibiotics to AVOID

Never use these antibiotics for cat bites as they lack adequate coverage against Pasteurella multocida: 1, 7

• First-generation cephalosporins (e.g., cephalexin)
• Macrolides (e.g., erythromycin, azithromycin)
• Clindamycin as monotherapy
• Penicillinase-resistant penicillins (e.g., dicloxacillin)

Critical Wound Management Steps

Irrigation and Debridement

• Copiously irrigate with sterile normal saline using a 20-mL or larger syringe to adequately cleanse the wound 6
• Perform cautious debridement of devitalized tissue only 1
• Explore the wound for tendon, bone, or joint involvement 6

Wound Closure Decision

Primary wound closure is NOT recommended for cat bite wounds with one critical exception: 1

• Do NOT close: Hand wounds, puncture wounds, or any wound with signs of infection
• Exception: Facial wounds may be closed after copious irrigation, cautious debridement, and initiation of preemptive antibiotics 1
• Other wounds may be approximated (edges brought together without suturing) 1

The rationale: Closing hand wounds significantly increases infection rates, and hand bites already carry the highest complication risk. 5

Tetanus Prophylaxis

Administer tetanus prophylaxis based on vaccination history: 1

• If >10 years since last tetanus vaccination: Give tetanus toxoid booster
• If >5 years for dirty/contaminated wounds: Give booster
• Tdap is preferred over Td if the patient has not previously received Tdap
• Complete the primary series if the patient never received one

Red Flags Requiring Urgent Attention

Watch for these complications that indicate deep tissue involvement: 5

• Pain disproportionate to the injury, especially near bones or joints (suggests periosteal penetration or septic arthritis)
• Rapidly developing cellulitis within 12-24 hours (classic for Pasteurella infection) 4
• Serosanguineous or purulent drainage 4
• Limited range of motion or inability to flex/extend digits
• Fever or systemic symptoms

Management of Complications

If osteomyelitis, septic arthritis, or deep space infection develops: 7

• Requires surgical drainage and debridement 5
• Extended antibiotic therapy for 4-6 weeks (not just 3-5 days) 7
• Consider IV antibiotics: ampicillin-sulbactam, piperacillin-tazobactam, or ertapenem 1

Common Pitfalls to Avoid

• Do not underestimate cat bites, especially to the hand—they appear deceptively minor but carry high infection risk 5, 3
• Do not close puncture wounds or hand wounds—this dramatically increases infection rates 1, 5
• Do not delay antibiotic prophylaxis—Pasteurella infections develop rapidly, often within 12-24 hours 4
• Do not use inadequate antibiotics—first-generation cephalosporins and macrolides will miss Pasteurella 1, 7
• Do not skip wound exploration—failure to identify tendon or bone involvement leads to delayed diagnosis of serious complications 6

Duration of Antibiotic Therapy

• Prophylaxis for uninfected wounds: 3-5 days 7
• Treatment of established infection: 7-10 days minimum 7
• Deep tissue infections (osteomyelitis, septic arthritis): 4-6 weeks 7