Animal Bites

GENERAL PRINCIPLES

• Management includes copious irrigation, culturing visibly infected wounds, and obtaining imaging to exclude fracture, foreign body, or joint space involvement.

• Most wounds should not be sutured unless they occur on the face and have been thoroughly irrigated.

TREATMENT

• Antimicrobial therapy is given to treat infection and as prophylaxis for high-risk bite wounds based on severity (e.g., moderate to severe), location (e.g., hands, genitalia, near joints), type of animal, immune status (e.g., diabetes mellitus, asplenia, immunosuppression), and mechanism of injury (e.g., puncture, crush injury). Tetanus toxoid should be administered if the patient has been previously vaccinated but has not received a booster in the last 5 years.

• Prophylactic antibiotic therapy with amoxicillin-clavulanate 875 mg/125 mg PO q12h for 3-5 days should usually be administered.

SPECIAL CONSIDERATIONS

• Dog bites: Normal oral flora includes Pasteurella multocida, streptococci, staphylococci, and Capnocytophaga canimorsus. Dog bites comprise 80% of animal bites, but only 5% of such bites become infected. For infected dog bite wounds, amoxicillin-clavulanate, or clindamycin plus ciprofloxacin, is appropriate.

• Cat bites: Normal oral flora includes P. multocida and S. aureus. Because more than 80% of cat bites become infected, prophylaxis with amoxicillin-clavulanate should be routinely provided. Cephalosporins should not be used. Bartonellosis can also develop after a cat bite.

• Wild animal bites: Amoxicillin-clavulanate is a good choice for prophylaxis and empiric treatment for most animal bites. Monkey bites should be treated with acyclovir because of the risk of Herpesvirus simiae (B virus).

• Rabies

î Rabies causes an invariably fatal neurologic disease classically manifesting with hydrophobia, aerophobia, pharyngeal spasm, seizures, and coma.

î The need for rabies vaccination and immunoglobulin prophylaxis (see Appendix A, Immunizations and Postexposure Therapies) should be determined after any animal bite. Risk of rabies depends on the animal species and geographic location. In the US, most recent indigenous cases have been associated with bats, whereas dog bites account for the vast majority of human cases in the developing world.

î Regardless of species, if the animal is rabid or suspected to be rabid, the human diploid vaccine and rabies immunoglobulin should be administered immediately. Bites by domestic animals rarely require prophylaxis unless the condition of the animal is unknown. Public health authorities should be consulted to determine whether prophylaxis is recommended for other types of animal bites.