What is the recommended antibiotic management for dog bites at high risk of infection?

Antibiotic Management for High-Risk Dog Bites

For dog bites at high risk of infection, initiate preemptive antibiotic therapy with amoxicillin-clavulanate 875/125 mg twice daily for 3-5 days. 1

Defining High-Risk Dog Bites Requiring Antibiotics

High-risk dog bites that warrant preemptive antibiotic therapy include: 1

• Moderate to severe injuries, especially puncture wounds that may penetrate periosteum or joint capsules 1
• Location-specific wounds: hand, face, foot, or genital area injuries 1
• Host factors: immunocompromised patients, asplenic individuals, or those with advanced liver disease 1
• Preexisting or resultant edema of the affected area 1
• Patients with implants such as artificial heart valves 1

Important timing consideration: Antibiotics should NOT be given if the patient presents ≥24 hours after the bite without clinical signs of infection. 1

First-Line Antibiotic Regimen

Amoxicillin-clavulanate is the preferred agent because it provides coverage against the polymicrobial flora of dog bites, including both aerobic and anaerobic bacteria. 1, 2

Specific pathogens covered include:

• Pasteurella multocida (most common in dog bites) 1
• Staphylococcus aureus and streptococci 1
• Capnocytophaga canimorsus (can cause severe septicemia, especially in immunocompromised patients with 23-31% mortality) 3
• Anaerobes (Fusobacterium, Prevotella, Bacteroides, Porphyromonas) 1

Dosing:

• Oral: Amoxicillin-clavulanate 875/125 mg twice daily 1, 2
• Duration: 3-5 days for preemptive therapy 1
• Extended therapy: 2-4 weeks may be necessary if complications like osteomyelitis or septic arthritis develop 2

Alternative Regimens for Penicillin Allergy

Doxycycline 100 mg twice daily is the preferred alternative, with excellent activity against Pasteurella multocida, though some streptococci may be resistant. 1, 2

Intravenous options for severe infections:

• Ampicillin-sulbactam 1.5-3.0 g every 6-8 hours 1
• Piperacillin-tazobactam 3.37 g every 6-8 hours 1

Critical Wound Management Principles

Beyond antibiotics, proper wound care is equally—if not more—important for preventing infection: 1

• Copious irrigation with sterile normal saline using a 20-mL or larger syringe 2, 4
• Avoid high-pressure irrigation, as it may spread bacteria into deeper tissue layers 1
• Careful debridement of devitalized tissue while preserving viable tissue, especially for facial wounds 2
• Exploration for tendon, bone, or joint involvement 2, 4

Wound Closure Considerations:

• Facial wounds: Primary closure is recommended after thorough cleaning due to rich vascular supply and cosmetic importance 2, 5
• Other locations: Delayed closure may be preferred for high-risk or already infected wounds 5

Additional Required Interventions

Tetanus Prophylaxis:

• Administer if vaccination is not current within the past 5 years for dirty wounds 2

Rabies Prophylaxis:

• Consult local health officials to determine if rabies post-exposure prophylaxis is indicated 1, 2
• If indicated, provide both rabies immunoglobulin and vaccine for previously unvaccinated individuals 2

Common Pitfalls to Avoid

Do NOT use these antibiotics as monotherapy for dog bites, as they have poor activity against Pasteurella multocida: 2

• First-generation cephalosporins
• Macrolides
• Clindamycin alone

Do NOT rely on topical antibiotics like bacitracin, as they cannot adequately address the polymicrobial flora of bite wounds. 2

Do NOT delay evaluation in immunocompromised patients, as they are at significantly higher risk for severe complications including septicemia, meningitis, and disseminated intravascular coagulation. 3

Monitoring and Follow-Up

Close monitoring for signs of infection is essential: 2

• Increasing pain, redness, or swelling
• Purulent discharge
• Fever or systemic symptoms

Elevation of the injured area is recommended to reduce swelling and accelerate healing. 2