What is the treatment for a cat bite?

Cat Bite Treatment

Cat bites require immediate thorough wound cleansing with soap and water for 15 minutes, and prophylactic antibiotics with amoxicillin-clavulanate should be started for all patients, particularly given the 30-50% infection rate—significantly higher than dog bites. 1, 2

Immediate Wound Management

• Irrigate all cat bite wounds thoroughly with soap and water for approximately 15 minutes to reduce infection risk and potential rabies transmission 2, 3
• Examine wounds carefully for tendon or bone involvement, and potential joint penetration—pain disproportionate to injury near a bone or joint suggests periosteal penetration 2, 3
• Hand wounds require particular attention as they carry the greatest risk of infection and serious complications including septic arthritis, osteomyelitis, and flexor tenosynovitis 4, 5, 6
• Debride necrotic tissue and remove foreign bodies, but avoid high-pressure irrigation as this may spread bacteria into deeper tissue layers 1

Antibiotic Prophylaxis (Critical for Cat Bites)

Cat bites have a 30-50% infection rate compared to only 5-25% for dog bites, making prophylactic antibiotics essential rather than optional. 1

• First-line: Amoxicillin-clavulanate is the recommended prophylactic antibiotic for all cat bite wounds 2, 3, 4
• For penicillin-allergic patients: Use doxycycline, or a fluoroquinolone plus an agent active against anaerobes, or clindamycin plus a fluoroquinolone 2, 3
• Avoid: First-generation cephalosporins, penicillinase-resistant penicillins, macrolides, and clindamycin alone—these have poor activity against Pasteurella multocida 3
• Duration: Typically 3-5 days for prophylaxis 1

The rationale for universal antibiotic prophylaxis in cat bites is compelling: Pasteurella multocida is isolated in over 50% of cat bite wounds and approximately 90% of cats carry this organism in their oral cavity 4, 7. Unlike dog bites where selective prophylaxis may be appropriate, the high infection rate and deep puncture nature of cat bites justify routine antibiotic use.

High-Risk Features Requiring Aggressive Management

Admit patients for IV antibiotics and surgical evaluation if any of the following are present:

• Hand or forearm wounds presenting >24 hours after injury with signs of infection (swelling, redness, limited painful mobilization) 6
• Deep puncture wounds, which are the most common type of cat bite and carry highest infection risk 5
• Full-thickness wounds 5
• Wounds involving joints, tendons, ligaments, or bones 3
• Immunocompromised patients or those with asplenia (risk of Capnocytophaga canimorsus sepsis) 2, 3

In one study, 67% of patients presenting late (>24 hours) with cat bites to the hand/forearm required hospital admission for complications including tendon lesions and purulent flexor tenosynovitis, with mean admission duration of 6 days 6.

Wound Closure Considerations

• Generally avoid primary closure of cat bite wounds due to high infection risk 1
• Exception: Facial wounds may be closed if seen early and properly cleaned, considering cosmetic factors 2
• Deep puncture wounds (the typical cat bite pattern) should be left open 5

Rabies and Tetanus Prophylaxis

• Assess rabies risk based on vaccination status of the cat, circumstances of the bite, and whether the cat can be observed for 10 days 2
• If rabies prophylaxis indicated: Administer both rabies immune globulin and rabies vaccine immediately 2
• Tetanus prophylaxis: Administer tetanus toxoid to patients with unknown or incomplete tetanus immunization 2, 3
• Consult local health department about rabies prevalence in your geographic area 1

Microbiology and Complications to Monitor

Cat bite wounds are polymicrobial with mixed aerobic and anaerobic bacteria: 8

• Pasteurella multocida (present in >50% of infected cat bites and ~90% of cat oral cavities) 4, 7
• Staphylococci and Streptococci 1
• Anaerobes including Fusobacterium, Prevotella, Bacteroides, and Porphyromonas species 1
• Bartonella henselae (cat scratch disease) 1

Serious complications include:

• Septic arthritis and osteomyelitis 2, 3
• Flexor tenosynovitis (particularly hand wounds) 6
• Subcutaneous abscess formation and tendonitis 2, 3
• Bacteremia and sepsis (especially Capnocytophaga canimorsus in asplenic patients) 2, 3

Common Pitfalls to Avoid

• Do not underestimate cat bites—their narrow, deep puncture wounds inoculate bacteria into deep tissues and have double the infection rate of dog bites 8
• Do not delay treatment—wounds presenting >24 hours after injury have significantly higher complication rates requiring admission 6
• Do not use inadequate antibiotic coverage—single agents without anaerobic coverage will fail against the polymicrobial flora 3
• Do not forget to wash hands after handling cats and avoid allowing cats to lick open wounds, particularly in immunocompromised patients 1