What is the best approach for managing a cat bite in a patient, considering potential infections and underlying medical conditions?

Management of Cat Bites

For cat bites, immediately initiate amoxicillin-clavulanate 875/125 mg twice daily as first-line therapy, as this provides optimal coverage against Pasteurella multocida (present in 70-75% of infected cat bites) and other common pathogens. 1, 2

Immediate Wound Management

• Thoroughly irrigate the wound with sterile normal saline using a 20-mL or larger syringe to remove debris and reduce bacterial load 2, 3
• Avoid high-pressure irrigation as this may drive bacteria deeper into tissues 1
• Explore the wound for tendon, bone, or joint involvement, especially in hand wounds where complications are more common 1, 2
• Debride only if significant devitalized tissue is present 2

Antibiotic Therapy

First-Line Treatment

• Amoxicillin-clavulanate 875/125 mg twice daily orally is the definitive first-line agent 1, 2
• This combination provides essential coverage against P. multocida (isolated in 70-75% of infected cat bites), staphylococci, streptococci, and anaerobes 1, 4
• Cat bites have a 30-50% infection rate, significantly higher than dog bites (5-25%), making prophylactic antibiotics critical 1

Alternative Oral Regimens (for penicillin allergy)

• Doxycycline 100 mg twice daily - excellent Pasteurella activity 2
• Fluoroquinolones (ciprofloxacin 500-750 mg twice daily or levofloxacin 750 mg daily) plus metronidazole for anaerobic coverage 1, 2
• Trimethoprim-sulfamethoxazole plus metronidazole 1, 2

Intravenous Options (for severe infections)

• Ampicillin-sulbactam, piperacillin-tazobactam, or carbapenems (ertapenem, imipenem, meropenem) 1
• Second-generation cephalosporins such as cefoxitin 1

Critical Pitfall: Avoid These Antibiotics

• Never use first-generation cephalosporins (cephalexin), dicloxacillin, macrolides (erythromycin), or clindamycin as monotherapy - all have poor activity against P. multocida and will fail 1, 2

High-Risk Situations Requiring Aggressive Treatment

Mandatory antibiotic prophylaxis for:

• Deep puncture wounds (cat teeth create deep, narrow wounds with high infection risk) 1, 2
• Hand, foot, face, or near-joint wounds 1, 2
• Immunocompromised patients (risk of fulminant sepsis) 1, 5
• Wounds presenting within 24 hours of injury 1
• Patients with prosthetic joints or heart valves 1

Treatment Duration

• Standard course: 3-5 days for prophylaxis 1
• 7-14 days for established infection 1
• 4-6 weeks for complications (osteomyelitis, septic arthritis, tendonitis) 1

Special Considerations

Diabetic Patients

• Require 1-2 weeks minimum antibiotic therapy for mild infections 2
• Extend to 3-4 weeks if extensive infection, slow healing, or severe peripheral artery disease 2
• Ensure optimal wound care with debridement and off-loading 2
• Early surgical consultation for deep abscess or extensive necrosis 2

Rapid Onset Infections

• Cellulitis developing within 12-24 hours strongly suggests P. multocida 6
• This pathogen causes rapidly developing cellulitis with serosanguineous or purulent drainage 6
• Can progress to osteomyelitis if inadequately treated 6

Cat Scratch Disease (Bartonella henselae)

• If lymphadenopathy develops, treat with azithromycin 500 mg day 1, then 250 mg daily for 4 additional days (adults >45 kg) 2
• For children <45 kg: 10 mg/kg day 1, then 5 mg/kg for 4 days 2

Essential Ancillary Management

• Update tetanus prophylaxis if not current 2
• Assess rabies risk for unknown or feral cats and provide post-exposure prophylaxis (immune globulin plus vaccination on days 0,3,7,14) if indicated 2, 3
• Elevate the injured extremity to accelerate healing if swollen 1, 2

Red Flags Requiring Urgent Evaluation

• Pain disproportionate to injury (suggests periosteal penetration or deep infection) 1
• Hand wounds (higher risk of septic arthritis, osteomyelitis, tendonitis) 1, 2
• Systemic signs (fever, chills, lymphangitis) 2
• Rapid progression within hours (potential fulminant sepsis, especially in immunocompromised) 5

Follow-Up

• Instruct patients to return immediately if increasing pain, redness, swelling, purulent drainage, or fever develop 2
• Monitor closely for complications including septic arthritis, osteomyelitis, abscess formation, or bacteremia 1, 2
• Approximately 90% of cats carry P. multocida in their oral cavity, making infection highly likely without proper treatment 7