What is the first line treatment for a patient with no known allergies or significant medical history presenting with a cat bite?

First-Line Treatment for Cat Bite

For a patient with no known allergies presenting with a cat bite, initiate immediate wound irrigation with soap and water followed by amoxicillin-clavulanate 875/125 mg orally twice daily as first-line antimicrobial therapy. 1, 2

Immediate Wound Management

• Thoroughly wash the wound with soap and water immediately—this simple intervention markedly reduces rabies risk and bacterial load 1
• Copiously irrigate with sterile normal saline using a 20-mL or larger syringe to remove superficial debris 2, 3
• Deeper debridement is usually unnecessary unless significant devitalized tissue is present 2
• Explore the wound for tendon or bone involvement and possible foreign bodies 3

Antimicrobial Therapy: The Critical Component

Amoxicillin-clavulanate is the recommended first-line oral antibiotic for both prophylaxis and treatment of cat bites 1, 2, 4. This recommendation is particularly strong because:

• Cat bites carry a 30-50% infection risk, significantly higher than dog bites 2
• Pasteurella multocida is isolated from 75% of cat bite wounds and is highly susceptible to amoxicillin-clavulanate 1, 5
• Approximately 90% of domestic cats carry P. multocida in their oral cavity 5
• Cat bites have higher prevalence of anaerobes (65%) requiring broader coverage 1

Dosing

• Adults: Amoxicillin-clavulanate 875/125 mg orally twice daily 2
• This provides optimal coverage against Pasteurella multocida, staphylococci, streptococci, and anaerobes 1, 2

Alternative Regimens (for penicillin allergy)

• Doxycycline 100 mg twice daily is the preferred alternative with excellent Pasteurella activity 1, 2
• Fluoroquinolones (ciprofloxacin 500-750 mg twice daily or levofloxacin 750 mg daily) provide good Pasteurella coverage 1, 2
• Trimethoprim-sulfamethoxazole plus metronidazole can be used for combined aerobic/anaerobic coverage 1, 2

Important caveat: Clindamycin should NOT be used as monotherapy because it lacks adequate Pasteurella coverage despite good activity against staphylococci and anaerobes 2

High-Risk Situations Requiring Prophylactic Antibiotics

Prophylactic antibiotics are mandatory for 2, 3:

• Deep puncture wounds (cat bites are typically deep punctures with minimal crush injury) 1
• Wounds on hands, feet, face, or near joints 2
• Immunocompromised patients 2
• Any wound presenting more than 8-12 hours after injury 1

Cat bites to the hand carry the greatest infection risk and have higher rates of osteomyelitis and septic arthritis compared to dog bites 1, 4, 6

Tetanus and Rabies Considerations

• Evaluate tetanus immunization status and update if the last dose was more than 5 years ago for contaminated wounds or more than 10 years for clean wounds 1, 2, 3
• Assess rabies risk, particularly for bites from unknown, stray, or feral cats 1, 2
• For high-risk exposures, rabies postexposure prophylaxis consists of human rabies immune globulin (HRIG) plus vaccine on days 0,3,7,14, and 28 1, 3
• A healthy domestic cat can be observed for 10 days; if it remains healthy, rabies can be ruled out 1

Wound Closure Decisions

• Wounds may be closed if cosmetically favorable (such as facial wounds) or if gaping 3
• Exercise caution with primary closure due to high infection risk—consider delayed primary closure for high-risk wounds 7
• The decision should balance cosmetic factors against bacterial infection potential 1

Follow-Up Instructions

• Advise patients to return immediately if signs of infection develop: increasing pain, redness, swelling, purulent drainage, or fever 2
• Monitor specifically for complications including septic arthritis, osteomyelitis, or tendonitis, especially with hand wounds 2
• Elevation of the injured body part accelerates healing if swelling is present 2

Common Pitfalls to Avoid

• Do not underestimate cat bites because they appear minor—they have higher infection rates than dog bites despite less visible trauma 1, 6
• Do not use inadequate antibiotic coverage—monotherapy with agents lacking Pasteurella activity (like clindamycin alone or first-generation cephalosporins) will fail 2
• Do not delay treatment—patients presenting after 8-12 hours typically have established infection requiring more aggressive management 1