What is the best course of treatment for a patient with a cat bite?

Cat Bite Treatment

Start amoxicillin-clavulanate 875/125 mg orally twice daily immediately for all cat bite wounds, as this provides optimal coverage against the polymicrobial flora that causes infection in up to 80% of cases. 1, 2

Immediate Wound Management

• Thoroughly wash and irrigate the wound with soap and water for at least 15 minutes to reduce bacterial load and potential rabies transmission 3, 2
• Consider using povidone-iodine solution as a virucidal agent during irrigation 3, 2
• Remove superficial debris and carefully examine for deep tissue involvement, including tendon penetration, bone involvement, or joint space violation 1, 2
• Do not suture infected wounds or wounds with high infection risk (hand wounds, puncture wounds, wounds presenting >8 hours after injury) 1
• Elevate the injured body part to accelerate healing and reduce swelling 1, 2

Antibiotic Selection

First-Line Therapy

• Amoxicillin-clavulanate 875/125 mg twice daily is the gold standard because it covers Pasteurella multocida (present in 75% of cat bites), staphylococci and streptococci (40% of cases), and anaerobes (65% of cases) 3, 1, 2

Alternative Oral Regimens (for penicillin allergy)

• Doxycycline 100 mg twice daily provides excellent coverage against P. multocida, though some streptococci may be resistant 1, 2
• Fluoroquinolone (ciprofloxacin, levofloxacin, or moxifloxacin) plus metronidazole or clindamycin for anaerobic coverage 3, 2
• Penicillin VK plus dicloxacillin (500 mg four times daily each) is another option 1

Antibiotics to AVOID

• Never use first-generation cephalosporins (cephalexin), penicillinase-resistant penicillins alone (dicloxacillin), macrolides (erythromycin), or clindamycin monotherapy as they have poor or absent activity against P. multocida and will result in treatment failure 3, 1, 2

Intravenous Options (for severe infections)

• Ampicillin-sulbactam, piperacillin-tazobactam, second-generation cephalosporins, or carbapenems for hospitalized patients 3, 1, 2

High-Risk Situations Requiring Aggressive Management

Hand Wounds

• All hand wounds require antibiotic prophylaxis regardless of appearance because they carry the highest infection risk and greatest potential for septic arthritis, osteomyelitis, and tendonitis 1, 2, 4
• Cat bites over joints, tendons, or bones have particularly high complication rates 2, 4
• Even small external wounds can harbor deep infections 5, 4

Immunocompromised Patients

• Patients with diabetes, liver disease, asplenia, or on immunosuppressive therapy require more aggressive treatment due to risk of disseminated Capnocytophaga canimorsus infection, which can cause septic shock, meningitis, and endocarditis 1, 2

Indications for Hospitalization

• Systemic signs of infection (fever, lymphangitis, lymphadenopathy) 1
• Rapidly progressing infection despite oral antibiotics 1
• Deep tissue involvement (tendon, bone, joint) 1, 2
• Immunocompromised host 1
• Hand wounds with significant swelling or functional impairment 4

Rabies and Tetanus Prophylaxis

Rabies Assessment

• A healthy domestic cat should be confined and observed for 10 days 3, 1
• Any illness in the cat during observation warrants immediate euthanasia and rabies testing 3
• Stray or unwanted cats should be euthanized immediately and tested for rabies 3
• If rabies prophylaxis is indicated, administer both rabies immune globulin (RIG) and rabies vaccine series (5 doses over 28 days) 3, 2

Tetanus Prophylaxis

• Update tetanus vaccination if status is outdated or unknown 3, 2

Follow-Up Protocol

• All outpatients must be followed up within 24 hours either by phone or office visit to assess for progression of infection 1
• If infection progresses despite appropriate antibiotic therapy, hospitalize immediately 1
• Provide intensive hand physiotherapy after a short period of immobilization for hand wounds 4

Critical Pitfalls to Avoid

• Never rely on topical antibiotics alone without systemic coverage 1
• Do not delay treatment, as this leads to complications including septic arthritis, osteomyelitis, tendonitis, and bacteremia 1, 2
• Do not underestimate small puncture wounds, especially on the hand, as they frequently cause deep infections 5, 4
• Do not use mupirocin for cat bites, as it does not adequately penetrate to reach deep-seated infections 1