Can doxycycline be used to treat dog bites?

Doxycycline for Dog Bite Treatment

Doxycycline is an effective alternative oral antibiotic for treating dog bites, particularly when amoxicillin-clavulanate (the first-line treatment) cannot be used. 1

Microbiology of Dog Bites

Dog bites typically involve polymicrobial infections with both aerobic and anaerobic bacteria:

• Pasteurella species (found in 50% of dog bite wounds)
• Staphylococci and streptococci (found in ~40% of bites)
• Capnocytophaga canimorsus (particularly concerning in asplenic or hepatic disease patients)
• Anaerobes including Bacteroides, fusobacteria, Porphyromonas, and Prevotella species 1

The average dog bite wound yields approximately 5 different bacterial isolates, with about 60% containing mixed aerobic and anaerobic bacteria 1.

Antibiotic Treatment Algorithm

First-Line Treatment:

• Amoxicillin-clavulanate (studied in clinical trials and recommended with B-II level evidence) 1, 2, 3

Alternative Oral Options (when first-line cannot be used):

• Doxycycline (100mg twice daily) 1, 4
• Penicillin VK plus dicloxacillin 1
• Sulfamethoxazole-trimethoprim plus metronidazole 4

Intravenous Options (for severe infections):

• β-lactam/β-lactamase combinations (e.g., ampicillin-sulbactam)
• Piperacillin/tazobactam
• Second-generation cephalosporins (e.g., cefoxitin)
• Carbapenems (e.g., ertapenem, imipenem, meropenem) 1

Antibiotics to Avoid

The following antibiotics have poor in vitro activity against Pasteurella multocida and should be avoided for dog bite treatment:

• First-generation cephalosporins (e.g., cephalexin)
• Penicillinase-resistant penicillins (e.g., dicloxacillin)
• Macrolides (e.g., erythromycin)
• Clindamycin 1

Indications for Antibiotic Prophylaxis

Prophylactic antibiotics should be considered for:

• Puncture wounds
• Wounds to the hand, feet, face, or genitals
• Wounds that have undergone primary closure
• Moderate or severe bite wounds
• Immunocompromised or asplenic patients 5

Treatment Duration

Standard treatment duration for uncomplicated skin infections from dog bites is 5-7 days 4.

Additional Management

1. Wound care:

   • Clean and irrigate with warm water or normal saline
   • Remove foreign bodies and devitalized tissue
   • Examine neurovascular function and joint movement 2

2. Wound closure:

   • Primary closure may be performed for cosmetically important areas (face) or gaping wounds if risk of infection is low 3

3. Prophylaxis considerations:

   • Evaluate need for tetanus vaccination
   • Assess need for rabies post-exposure prophylaxis 2, 3

Special Considerations

• Hand bites are at higher risk for complications including septic arthritis, osteomyelitis, and tendonitis
• Elevation of the injured body part accelerates healing if swelling is present
• Pain disproportionate to injury severity near a bone or joint may suggest periosteal penetration 1

Monitoring

Patients should be evaluated for improvement within 48-72 hours of initiating treatment. If infection has not improved within 5 days, treatment duration may need to be extended 4.