What is the recommended outpatient antibiotic for a dog bite wound on the hand in a patient without a penicillin allergy?

Amoxicillin-Clavulanate 875/125 mg Twice Daily for 3-5 Days

For a dog bite to the hand in an outpatient without penicillin allergy, prescribe amoxicillin-clavulanate 875/125 mg orally twice daily for 3-5 days. This is the first-line antibiotic choice with strong guideline support for this high-risk wound location 1.

Why Hand Bites Require Antibiotics

Hand bites are specifically designated as high-risk wounds requiring preemptive antimicrobial therapy 1. The IDSA guidelines explicitly recommend 3-5 days of antibiotics for:

• Moderate to severe injuries, especially to the hand or face
• Injuries that may have penetrated periosteum or joint capsule
• Puncture wounds 1

Hand wounds carry greater risk of serious complications including septic arthritis, osteomyelitis, and tendonitis compared to bites on fleshy body parts 2.

Why Amoxicillin-Clavulanate is First-Line

Amoxicillin-clavulanate provides coverage against both aerobic and anaerobic bacteria that commonly infect dog bite wounds 1, 3, 1. Dog bite wounds yield an average of 5 bacterial species, with approximately 60% containing mixed aerobic and anaerobic organisms 2.

Key Pathogens Covered:

• Pasteurella multocida (isolated from 50% of dog bites) 2
• Staphylococci and streptococci (found in ~40% of bites) 2
• Anaerobes including Bacteroides, Fusobacterium, and Porphyromonas species 2
• Capnocytophaga canimorsus (can cause fatal sepsis, especially in asplenic or liver disease patients) 2

Alternative Regimens (If Amoxicillin-Clavulanate Unavailable)

If amoxicillin-clavulanate is not available, acceptable alternatives include 1, 3, 1:

Single-agent options:

• Doxycycline 100 mg twice daily (excellent activity against P. multocida, but some streptococci resistant) 1, 3, 1
• Moxifloxacin 400 mg daily (provides both aerobic and anaerobic coverage as monotherapy) 3, 1

Combination regimens:

• Penicillin VK 500 mg four times daily PLUS dicloxacillin 500 mg four times daily 1, 3, 1
• Levofloxacin 750 mg daily PLUS metronidazole 500 mg three times daily 3, 1

Critical Pitfalls to Avoid

Do NOT use these antibiotics for dog bites as they have poor activity against P. multocida 2:

• First-generation cephalosporins (cephalexin)
• Penicillinase-resistant penicillins alone (dicloxacillin monotherapy)
• Macrolides (erythromycin, azithromycin)
• Clindamycin monotherapy

These agents will miss Pasteurella, the most common pathogen in dog bites.

Additional Essential Management

Beyond antibiotics, ensure:

1. Wound care: Copious irrigation with sterile normal saline and cautious superficial debridement 2

2. Do NOT primarily close hand bite wounds - they should be left open or approximated at most, as closure increases infection risk 1

3. Tetanus prophylaxis: Administer Tdap if not given within 10 years (or 5 years for dirty wounds) 1

4. Rabies assessment: Consult local health officials to determine if rabies prophylaxis is indicated 1

5. Elevation: Keep hand elevated for first few days to reduce swelling and accelerate healing 2

6. Follow-up within 24 hours to assess for progression of infection 2

When to Consider Hospitalization

Watch for signs requiring inpatient IV therapy:

• Pain disproportionate to injury (suggests periosteal penetration or joint involvement) 2
• Rapidly progressive infection despite oral antibiotics
• Signs of septic arthritis or osteomyelitis
• Systemic signs of infection

For hospitalized patients, use IV ampicillin-sulbactam 1.5-3.0 g every 6-8 hours or piperacillin-tazobactam 3.37 g every 6-8 hours 1, 3, 1.