What is the appropriate management for a cat bite, including wound irrigation, tetanus prophylaxis, empiric antibiotics, and rabies post‑exposure prophylaxis?

Management of Cat Bites

Start amoxicillin-clavulanate 875/125 mg twice daily immediately for all cat bite patients, regardless of wound appearance, as cat bites have a 30-50% infection rate and require prophylactic antibiotics. 1

Immediate Wound Care

• Irrigate the wound copiously with sterile normal saline using a 20-mL or larger syringe to mechanically remove bacteria and debris 1
• Thoroughly wash all bite wounds with soap and water, which has been shown in animal studies to markedly reduce rabies transmission 2
• Remove only superficial debris; avoid aggressive deep debridement unless significant devitalized tissue is present, as this can enlarge the wound and impair closure 1
• Do not primarily close cat bite wounds except facial wounds managed by specialists with meticulous irrigation and prophylactic antibiotics 2
• Elevate the affected extremity to reduce swelling and accelerate healing 2, 1

Antibiotic Prophylaxis

First-Line Regimen

• Amoxicillin-clavulanate 875/125 mg orally twice daily is the gold standard due to excellent coverage against Pasteurella multocida (present in ~90% of cat mouths and >50% of infected cat bites), staphylococci, streptococci, and anaerobes 1, 3, 4
• Cat bites yield an average of 5 different bacterial isolates with 60% containing mixed aerobic-anaerobic bacteria 1
• Duration: 3-5 days for uncomplicated prophylaxis 1

Penicillin Allergy Alternatives

• Doxycycline 100 mg orally twice daily with excellent P. multocida activity 1
• Moxifloxacin 400 mg orally daily as monotherapy with good anaerobic coverage 1

When to Use IV Antibiotics

• Switch to IV therapy for established infection with systemic signs (fever, lymphangitis), deep tissue involvement, or immunocompromised patients with moderate-to-severe injuries 1
• IV options: ampicillin-sulbactam, piperacillin-tazobactam, or carbapenems (ertapenem, imipenem, meropenem) 2, 1
• Transition to oral amoxicillin-clavulanate once clinical improvement occurs 1

High-Risk Scenarios Requiring Special Attention

Hand Bites (Highest Risk)

• Hand wounds have the greatest infection risk and require early prophylactic antibiotics, close observation with 24-hour follow-up, and low threshold for imaging if bone/joint involvement suspected 1, 5
• Pain disproportionate to injury near bone or joint suggests periosteal penetration 2
• Prophylactic antibiotics reduce infection in hand bites (NNT = 4) 6

Other High-Risk Wounds

• Bites to the foot, face, or near joints require prophylactic antibiotics 1
• Deep puncture wounds (typical of cat bites due to sharp teeth) 1
• Immunocompromised patients 1
• Wounds with edema or crushing injury 7

Tetanus Prophylaxis

• Administer tetanus toxoid if not vaccinated within 10 years 2, 1
• Tdap is preferred over Td if Tdap has not been previously given 2
• For dirty wounds, give booster if >5 years since last dose 2

Rabies Considerations

Domestic Cats

• A healthy domestic cat that bites should be confined and observed for 10 days 2, 1
• Any illness during observation should be evaluated immediately by a veterinarian 2
• If the cat is stray, unwanted, or develops signs suggestive of rabies, it should be euthanized and tested for rabies 2, 1

Feral/Wild Cats

• Consider rabies post-exposure prophylaxis for all feral and wild cat bites 2, 1
• Consult local health department about rabies prevalence in your area 2
• Rabies prophylaxis includes rabies immunoglobulin on day 0 plus rabies vaccine series 2

Follow-Up and Monitoring

• Arrange follow-up within 24 hours, either by phone or office visit 2, 1
• Instruct patients to return immediately if they develop redness, swelling, foul-smelling drainage, increased pain, or fever 2
• If infection progresses despite appropriate antibiotics and wound care, hospitalization should be considered 2

Duration of Treatment for Complications

If infection develops despite prophylaxis:

• Cellulitis or soft tissue infection: 1-2 weeks (up to 3-4 weeks if extensive or slow to resolve) 1
• Septic arthritis: 3-4 weeks 2, 1
• Osteomyelitis: 4-6 weeks 2, 1
• Tenosynovitis: 3-4 weeks 1

Common Pitfalls to Avoid

• Never assume a cat bite is "just a scratch" – the 30-50% infection rate demands prophylactic antibiotics for all cat bites 1
• Avoid using first-generation cephalosporins or penicillin alone, as many oral anaerobes produce β-lactamases 2
• Do not delay treatment waiting for culture results; empiric therapy is essential 1
• Hand wounds require particularly aggressive management due to proximity to tendons, joints, and bones 1, 5