Treatment for Cat Scratch
For a simple cat scratch, immediately irrigate the wound thoroughly with soap and water, then apply amoxicillin-clavulanate 875/125 mg twice daily if the wound is deep, on the hand/face/near joints, or the patient is immunocompromised. 1
Immediate Wound Management
All cat scratches require thorough cleansing as the first critical step:
- Irrigate immediately with copious amounts of soap and water (100-1000 mL of tap water) to reduce bacterial load and prevent both bacterial infection and Bartonella henselae transmission 2
- For stray cat scratches, add povidone-iodine solution as a virucidal agent, particularly important for rabies risk 2
- After cleaning, apply topical antibiotic ointment and cover with a clean occlusive dressing, changing daily 2
- Verify and update tetanus immunization status 1, 2
Antibiotic Prophylaxis Decision
Prophylactic antibiotics are indicated for: 1
- Deep wounds
- Wounds on hands, feet, face, or near joints
- Immunocompromised patients
- Cat scratches carry approximately 10-20% infection risk (higher than the 30-50% for actual bites) 1
First-line antibiotic: Amoxicillin-clavulanate 875/125 mg twice daily provides optimal coverage against Pasteurella multocida and other common pathogens from cat scratches 1
For penicillin-allergic patients: 1
- Doxycycline 100 mg twice daily (excellent Pasteurella activity)
- Fluoroquinolones: ciprofloxacin 500-750 mg twice daily or levofloxacin 750 mg daily
- TMP-SMX plus metronidazole for combined aerobic/anaerobic coverage
Avoid clindamycin monotherapy as it misses P. multocida coverage despite good activity against staphylococci, streptococci, and anaerobes 1
Special Considerations for Stray Cats
Stray cat scratches require heightened vigilance: 2
- If the cat cannot be captured for 10-day observation, initiate rabies postexposure prophylaxis immediately with both rabies immune globulin (RIG) and vaccine series 2
- Stray cats have higher rates of Bartonella infection and unknown rabies vaccination status 2
Cat Scratch Disease (CSD) Development
If lymphadenopathy develops 1-3 weeks after the scratch, suspect cat scratch disease caused by Bartonella henselae: 3, 4
Treatment for CSD:
- Azithromycin is first-line: 500 mg on day 1, then 250 mg daily for 4 additional days (for patients >45 kg) 1, 3
- For patients <45 kg: 10 mg/kg on day 1, then 5 mg/kg daily for 4 additional days 1, 3
- Alternative if azithromycin contraindicated: Doxycycline 100 mg twice daily for 10-14 days 3
- Erythromycin 500 mg four times daily is another alternative 3
Most cases of CSD are self-limited and resolve within 1-6 months without treatment, but azithromycin has been shown to speed recovery 3, 4
Red Flags Requiring Urgent Evaluation
Seek immediate medical attention if: 2
- Increasing redness, swelling, warmth, or pain around the wound
- Red streaks extending from the wound (lymphangitis)
- Fever or systemic symptoms
- Lymph node enlargement (typically 1-3 weeks post-scratch)
Severe or Disseminated Disease
For immunocompromised patients (especially HIV with CD4+ <100 cells/µL): 3
- Risk of bacillary angiomatosis, peliosis hepatis, or CNS involvement
- Requires erythromycin or doxycycline for >3 months until CD4+ >200 cells/µL for >6 months 3
- Doxycycline with or without rifampin is preferred for CNS bartonellosis 3
For hepatosplenic involvement: Gentamicin has shown 73% efficacy with rapid response within 48 hours, though evidence quality is lower than azithromycin 3, 5
Prevention Counseling
For patients with cats (especially immunocompromised): 6, 3
- Choose cats >1 year old in good health to reduce Bartonella risk
- Avoid rough play and situations where scratches are likely
- Implement comprehensive flea control (fleas transmit Bartonella between cats)
- Wash any cat-associated wounds promptly
- Do not allow cats to lick open wounds
- Keep cats indoors and do not allow them to hunt
Common pitfall: Do not test cats for Bartonella infection—this provides no benefit to diagnosis or management 3