Management of a dog bite includes treatment centered on local wounds as well as consideration of antimicrobials, tetanus prophylaxis, and rabies prophylaxis. Wound management is as important as use of antimicrobials in preventing infection.4 It is estimated that infection rates can be reduced more than 80% with proper irrigation.9 Additionally, a randomized controlled trial specific to dog-bite wounds showed that wound debridement further reduced infection rate to <5%.9 Be cautious, however. Overaggressive irrigation and debridement can increase wound devitalization.
Treatment begins with immobilization and elevation of the affected area. If the skin is intact, wash with soap and water. Open wounds need to be irrigated with normal saline at 250 mL/inch of wound. An 18-gauge catheter attached to a 35-mL syringe will provide adequate pressure for proper irrigation.2 A meta-analysis clearly found that copious irrigation significantly reduced infection rate by more than 50%.10 Foreign debris needs to be completely removed from the wound to prevent complications; however, not all wounds require surgical debridement. Only devitalized and necrotic tissue should be debrided. Puncture wounds should not be debrided. Smooth wound edges are essential for optimal healing and cosmetic appearance.
Many wounds should not be closed. Those older than 24 hours with signs of infection are best left to heal by secondary intention. Wounds with a high risk of complication and infection (e.g., hand and deep puncture wounds) should also be allowed to heal by secondary intention. A randomized controlled trial found that delayed wound closure further reduced infection rates.9 For cosmetic reasons, consult a plastic surgeon for the treatment of wounds of the face, neck, or other highly visible areas.11
Not all wounds require antimicrobial prophylaxis. Indiscriminate prescription of antibiotics increases the chance of adverse reactions and future resistance. Additionally, most randomized controlled trials reviewed found that antibiotic use did not show a lower infection rate except in high-risk situations.12 Accordingly, antibiotics should be prescribed in the following situations: crush injuries, hand injuries, genital injuries, puncture wounds, and wounds with bone and joint involvement.13 Patients with such comorbid factors as immunosuppression, diabetes, and asplenism also require antibiotics.12 In such cases, a broad-spectrum beta-lactamase-resistant antibiotic should be utilized. A systematic review examining soft-tissue infections found amoxicillin/clavulanate to be the most effective treatment for these wounds because of the high incidence of Pasteurella infection.14 For patients allergic to penicillin, doxycycline is a good alternative; however, doxycycline should not be used during pregnancy or in children younger than 8 years.15 For pregnant patients allergic to penicillin, erythromycin may be substituted; these patients should be monitored closely for increased failure rates. Another alternative for the pediatric population is the combination of clindamycin and sulfamethoxazole-trimethoprim. Antibiotics administered for prophylaxis should be prescribed for five to seven days. Patients with infected wounds require antibiotics for a total of 10-14 days. Patients may also need hospitalization for infected dog bites.2
Clinicians must also consider tetanus and rabies immune globulin (RIG) administration. Patients should receive a tetanus toxoid if the last tetanus immunization was given more than five years prior. Patients whose tetanus status is unknown or who have received fewer than three lifetime tetanus immunizations should be given tetanus immunoglobulin and diphtheria/tetanus toxoid or age-equivalent vaccine.16 RIG prophylaxis is prudent if the dog has no records documenting vaccination status, cannot be captured for observation, or exhibits signs of rabies. RIG is dosed at 20 IU/kg of the patient’s body weight. If anatomically possible, give at least half of the dose into the wound. The remainder should be administered IM to the opposite extremity.17 Many patients will require only OTC analgesics for effective pain management. For more severe pain, acetaminophen with codeine every four to six hours for 24 hours is an appropriate regimen. Emotional support should be extended to the patient and family as needed. A mental-health referral may be made if deemed necessary by the provider.