What is the recommended treatment for a patient with a cat bite, considering potential risks of infection, tetanus, and rabies exposure?

Treatment for Cat Bite

Cat bites require immediate thorough wound cleansing, prophylactic antibiotics with amoxicillin-clavulanate, tetanus prophylaxis assessment, and rabies risk evaluation, with particularly aggressive management for hand wounds due to their high infection risk.

Immediate Wound Management

• Wash the wound immediately and thoroughly with soap and water for approximately 15 minutes to reduce infection risk and potential rabies transmission 1
• Irrigate with povidone-iodine solution after soap and water cleansing 1
• Examine the wound carefully for tendon or bone involvement, joint penetration, or pain disproportionate to the injury near bones or joints 1
• Explore the wound for possible foreign bodies and assess depth 2

Critical consideration: Cat bites create deep puncture wounds that seed bacteria into tissue, making them particularly prone to infection compared to dog bites 3, 4. Hand wounds from cat bites carry the greatest infection risk 3, 4.

Antibiotic Prophylaxis

Amoxicillin-clavulanate is the first-line prophylactic antibiotic for cat bite wounds 1, 3, 2. This is particularly critical because:

• Pasteurella multocida is isolated in over half of all cat bite wounds and can cause serious infection with severe complications 3
• Cat bites contain an average of 5 different aerobic and anaerobic bacteria per wound 5
• Puncture wounds and hand wounds have significantly higher infection rates 4

For penicillin-allergic patients, alternatives include 1:

• Doxycycline, OR
• Fluoroquinolone plus an agent active against anaerobes, OR
• Clindamycin plus a fluoroquinolone

Dosing from guidelines 5:

• Amoxicillin/clavulanate: 875/125 mg twice daily for adults
• Children: 25 mg/kg/day of the amoxicillin component in 2 divided doses

Tetanus Prophylaxis

• Assess tetanus immunization status and administer tetanus prophylaxis as indicated 1, 2
• Give tetanus toxoid to patients with unknown or incomplete tetanus immunization 1

Rabies Post-Exposure Prophylaxis

For healthy domestic cats in the US:

• Confine and observe the cat for 10 days to determine if it is shedding rabies virus at the time of the bite 1
• If the cat remains healthy for the full 10 days, no rabies prophylaxis is needed 1

Initiate immediate rabies post-exposure prophylaxis if 1:

• The cat is stray or unwanted
• Cannot be confined for observation
• Dies or develops illness before completing the 10-day observation period
• Shows signs suggestive of rabies during observation

For individuals never previously vaccinated against rabies 1:

• Human Rabies Immune Globulin (HRIG): 20 IU/kg body weight given once on day 0
• Rabies vaccine series: 5 doses on days 0,3,7,14, and 28

Wound Closure Considerations

• Consider wound closure for facial wounds if seen early and properly cleaned, balancing cosmetic factors against infection risk 1
• Avoid primary closure of puncture wounds, which are the most common type of cat bite and have the highest infection risk 4

High-Risk Factors Requiring Aggressive Management

Cat bite wounds are at particularly high risk for infection when 4:

• Located on the hand (45% of cat bites) 4
• Puncture wounds (56% of cat bites) 4
• Full-thickness wounds 4
• Longer time interval until treatment 4
• Inflicted by pet cats (paradoxically higher risk than stray cats in one study) 4

Potential Complications to Monitor

• Infectious complications including septic arthritis, osteomyelitis, subcutaneous abscess, tendonitis, and bacteremia 1
• Capnocytophaga canimorsus can cause fatal sepsis, especially in patients with asplenia or underlying hepatic disease 1
• Cat-scratch disease from Bartonella henselae may develop after cat bites 6

Critical Pitfalls to Avoid

• Never delay wound cleansing, as it is the first and most important intervention 1
• Do not underestimate the infection risk of seemingly minor puncture wounds from cat bites 3, 4
• Avoid initiating unnecessary post-exposure prophylaxis for healthy domestic cats that can be observed for 10 days 1
• Do not exceed the recommended HRIG dose, as excess HRIG can suppress active antibody production 1
• Do not dismiss hand wounds as trivial—they require prophylactic antibiotics due to high infection rates 7, 4