A 30-year-old man presents to the emergency room with a laceration over the 4th metacarpophalangeal (MCP) joint of his right hand. He reports that he is a mailman, and his closed fist was bitten by a dog while he was delivering mail yesterday. He reports pain but denies fevers, chills, drainage, or any other symptoms. The dog is up to date on vaccinations. His last tetanus vaccine was 3 years ago. He has no medical history and takes no medications. His temperature is 98.6°F (37.0°C), pulse is 80/min, blood pressure is 125/75 mmHg, and respirations are 16/min. Examination of the patient's right hand is shown in Figure A. Which of the following is the most appropriate next step in management?
Clindamycin
Amoxicillin-clavulanate
Clindamycin plus doxycycline
Wound closure and amoxicillin-clavulanate
Amoxicillin-clavulanate
This patient has suffered a clenched fist injury which are generally managed with irrigation and amoxicillin-clavulanate.

Amoxicillin-clavulanate is the usual first-line antibiotic for patients with a human or dog bite. Lacerations sustained from animal or human bites should not be sutured due to the risk of infection. Amoxicillin-clavulanate is first-line therapy for prophylaxis and treatment of human bites and dog bites, in general. Closed fist injuries put the patient at a high risk for osteomyelitis, septic arthritis, and tenosynovitis; therefore, prophylactic antibiotics are appropriate. Amoxicillin-clavulanate provides essential coverage against Pasturella multocida, commonly found in the mouths of dogs, cats, and other mammals. In patients with a penicillin allergy, agents such as TMP-SMX, doxycycline, or cefdinir paired with anaerobic coverage (clindamycin or metronidazole) is appropriate.

Presutti discusses the prevention and treatment of dog bites. Appropriate treatment consists of immediate, copious irrigation, assessment for risk of tetanus and rabies, and administration of prophylactic antibiotics as discussed above.

Figure A shows a dog bite wound over the 4th MCP of the right hand.

Incorrect Answers:
Answer B: Cephalexin does not cover species that are typically present in the mouths of dogs and other mammals and is therefore not an appropriate antibiotic choice for this patient as monotherapy.

Answer C: Clindamycin provides coverage of anaerobic species, but is not sufficient alone for treatment of this patient's injury.

Answer D: Clindamycin plus doxycycline may be appropriate coverage for a dog bite in a patient with an allergy to amoxicillin-clavulanate. However, this patient has no stated allergies and should receive amoxicillin-clavulanate.

Answer E: Wound closure and amoxicillin-clavulanate would not be appropriate. Lacerations sustained from dog or cat bites are not sutured closed due to the risk of infection.

Bullet Summary:
Amoxicillin-clavulanate is the first line antibiotic choice for patients with dog or cat bites.