What is the recommended treatment for an infected dog bite?

Treatment of Infected Dog Bite Wounds

Amoxicillin-clavulanate is the preferred antibiotic treatment for infected dog bite wounds, administered at a dose of 875/125 mg twice daily for 7-10 days. 1 This recommendation is based on its excellent coverage against Pasteurella multocida and other common bite wound pathogens commonly found in dog bites.

Initial Wound Management

1. Immediate wound care:

   • Thorough irrigation with sterile normal saline
   • Removal of superficial debris
   • Avoid primary closure of wounds (except for facial wounds) 1

2. Surgical considerations:

   • Primary surgical repair is appropriate for most clinically uninfected facial bite wounds
   • Delayed closure should be reserved for high-risk or already infected wounds 2
   • Surgical consultation is required for deep infections, abscess formation, compartment syndrome, or necrotizing infections 1

Antibiotic Therapy

First-line treatment:

• Amoxicillin-clavulanate (875/125 mg twice daily) 1
  • Provides coverage against P. multocida (found in 20-30% of dog bites), Staphylococcus aureus, and oral anaerobes 2, 3

Alternative options for penicillin-allergic patients:

• Doxycycline (excellent alternative) 1
• Clindamycin plus a fluoroquinolone
• Metronidazole plus a fluoroquinolone
• Trimethoprim-sulfamethoxazole 1

Antibiotics to avoid:

• First-generation cephalosporins
• Penicillinase-resistant penicillins
• Macrolides
• Clindamycin alone (due to poor activity against P. multocida) 1

Treatment Duration

• Localized infections: 7-10 days
• Severe or systemic infections: 10-14 days
• Complicated infections (osteomyelitis, septic arthritis): 3-4 weeks 1

Special Considerations

High-risk patients requiring broader spectrum antibiotics and closer monitoring:

• Immunocompromised individuals
• Elderly patients
• Patients with cirrhosis or asplenia
• Those with severe comorbidities 1

Indications for hospitalization:

• Severe infections with systemic symptoms
• Deep infections involving tendons or joints
• Hand infections (particularly high risk)
• Immunocompromised patients with moderate to severe infections 1

Additional prophylaxis to consider:

• Tetanus prophylaxis if vaccination is not current within 10 years
• Rabies immune globulin and vaccine series for high-risk exposures 1

Monitoring and Follow-up

• Assess response within 24-48 hours
• Monitor for signs of worsening infection
• Consider inflammatory markers and wound culture to guide antibiotic therapy if not improving 1

Special Anatomical Considerations

Hand bites deserve special attention as they have a higher risk of infection and complications. Evidence shows that prophylactic antibiotics significantly reduce infection rates in hand bites (NNT = 4) 4. The CDC recommends prophylactic antibiotics for all dog bites to the hand, even if not initially infected 1.

Common Pitfalls to Avoid

1. Inadequate wound irrigation - Thorough irrigation is as important as antibiotics for infection prevention
2. Using inappropriate antibiotics - First-generation cephalosporins have poor activity against P. multocida
3. Delayed treatment - Especially for hand wounds which can rapidly develop complications
4. Overlooking tetanus status - Always verify and update tetanus prophylaxis as needed
5. Premature wound closure - Except for facial wounds, primary closure should be avoided for infected bites

While older literature suggested dicloxacillin as a treatment option 5, more recent evidence strongly supports amoxicillin-clavulanate as the preferred choice due to its broader spectrum of activity against the polymicrobial nature of dog bite infections 1, 6.