This patient has experienced a dog bite and should receive treatment with amoxicillin-clavulanate. A 3- to 5-day course of prophylaxis (early preemptive therapy) with amoxicillin-clavulanate is recommended for patients who are immunosuppressed (including those with asplenia or significant liver disease); have moderate to severe wounds (particularly on the face or hand); have wounds near a joint or bone; or have wounds associated with significant crush injury or edema. Amoxicillin-clavulanate, an oral β-lactam/β-lactamase inhibitor, is a good choice because it has a broad spectrum of activity against the aerobic and anaerobic bacteria that constitute a dog's oral flora. Prompt wound irrigation and debridement, if appropriate, are also indicated. Each patient should also be evaluated for the need for tetanus and rabies prophylaxis.

Metronidazole provides anaerobic bacterial coverage but lacks coverage against aerobic bacteria in dogs' mouth flora. If used, it should be combined with a fluoroquinolone (such as ciprofloxacin or levofloxacin) or trimethoprim-sulfamethoxazole.

Patients with bite wounds should be vaccinated with tetanus toxoid if they have not received a tetanus immunization within the past 5 years because this type of wound is considered a “dirty” wound. Other wounds that are considered “dirty” include those contaminated with soil, saliva, dirt, or feces; avulsions; puncture wounds; and wounds resulting from burns, frostbite, crushing, or missiles. This patient has been immunized within this time period, so she does not require tetanus immunization. For a clean and minor wound, a booster dose of tetanus toxoid would be given to prevent tetanus if more than 10 years have elapsed since immunization.

Pursuing no additional therapy or evaluation would not be appropriate for this patient, who is receiving a tumor necrosis factor α inhibitor, which is an immunosuppressant. Although the patient has no signs or symptoms of infection, antibiotic prophylaxis is recommended as soon as possible after a bite to decrease the risk for infection.