What is the recommended management for a cat scratch in the emergency department?

Management of Cat Scratch in the Emergency Department

For cat scratch wounds in the emergency department, thorough wound cleaning followed by amoxicillin-clavulanate is recommended as first-line therapy to prevent infection, especially for deep wounds or those on the hands. 1

Initial Assessment and Wound Management

• Cat scratches should be thoroughly cleansed with sterile normal saline to remove superficial debris 1
• Deeper debridement is usually unnecessary unless there is significant devitalized tissue 1
• Evaluate the wound for depth, location, and time since injury, as these factors influence infection risk 2
• High-risk wounds include those on hands, deep punctures, and wounds in immunocompromised patients 2

Risk Factors for Infection

• Cat scratches have approximately 10-20% risk of infection, with higher rates for actual bites (30-50%) 1
• Factors associated with increased infection risk include:
  • Older patient age 2
  • Longer time interval until treatment (>8 hours) 2
  • Deeper wounds, especially punctures 2
  • Location on hands or lower extremities 2
  • Wounds from "pet" cats versus strays 2

Antimicrobial Therapy

When to Prescribe Antibiotics

• Prophylactic antibiotics are recommended for:
  • Deep wounds 1
  • Wounds on hands, feet, face, or near joints 1
  • Immunocompromised patients 1
  • Wounds with high risk of infection 1
• Antibiotics should not be given if the patient presents >24 hours after injury with no signs of infection 1

First-Line Antibiotic Therapy

• Amoxicillin-clavulanate is the recommended first-line oral therapy:
  • Adults: 875/125 mg twice daily 1
  • Children: 25 mg/kg/day of the amoxicillin component in 2 divided doses 1
• This provides coverage against Pasteurella multocida (present in 75% of cat-associated wounds) and other common pathogens 1

Alternative Antibiotic Options

For patients with penicillin allergy:

• Doxycycline 100 mg twice daily (adults) - excellent activity against Pasteurella multocida 1
• Trimethoprim-sulfamethoxazole plus metronidazole for anaerobic coverage 1
• Fluoroquinolones (e.g., ciprofloxacin 500-750 mg twice daily) may be used but may require additional anaerobic coverage 1

Antibiotics to Avoid

• First-generation cephalosporins (e.g., cephalexin)
• Dicloxacillin
• Erythromycin
• Clindamycin alone
• These have poor activity against Pasteurella multocida and should be avoided 1

Management of Cat Scratch Disease

If regional lymphadenopathy develops (suggesting cat scratch disease caused by Bartonella henselae):

• Azithromycin is recommended for cat scratch disease 1:
  • Patients >45 kg: 500 mg on day 1 followed by 250 mg for 4 additional days 1
  • Patients <45 kg: 10 mg/kg on day 1 and 5 mg/kg for 4 more days 1
• Most uncomplicated cases of cat scratch disease resolve spontaneously and may not require antibiotic treatment 3, 4

Special Considerations

• Evaluate tetanus immunization status and update if needed 1
• Consider rabies risk assessment for scratches from unknown or feral cats 1
• For immunocompromised patients, be vigilant for atypical presentations of cat scratch disease, including bacillary angiomatosis 1
• Elevation of the injured body part, especially if swollen, accelerates healing 1

Follow-Up

• Patients should be advised to return if signs of infection develop (increasing pain, redness, swelling, purulent drainage, fever) 1
• High-risk wounds may benefit from follow-up within 24-48 hours 2
• Monitor for complications such as septic arthritis, osteomyelitis, or tendonitis, especially with hand wounds 1