P DOG BITE WOUND

The most frequent complications of animal bites are infections. The risk of developing an infection and the severity of the infection are related to the type of animal, the location of the bite, the size of the wound, and the need to close the wound surgically. Bite wounds usually result in polymicrobial infections, with aerobic and anaerobic bacteria that come mainly from the animal’s oral flora but also from the child's skin and surrounding environment.

Pasteurella, Staphylococcus, and Streptococcus species, in addition to Capnocytophaga canimorsus, are the most common causes of infections from dog and cat bites. Eikenella corrodens is a common cause of infection from human bites. The general management for bite wounds is no different from what is usually recommended for other wounds. The site of the bite should first be vigorously washed with soap and water to reduce the bacterial inoculum, and any devitalized tissues should be debrided. There is still debate about whether clinically uninfected wounds should be sutured immediately or left open for 24 hours to permit evaluation for possible development of infection. However, delayed closure must be considered when a bite involves the head, hands, or feet; when a significant crush injury has occurred; or when there are clear signs of edema.

Antibiotic treatment is indicated for animal bite wounds that are at high risk for infection. These include skin-puncture wounds, wounds that require suturing (as in this case), and wounds that puncture joint or bone.

When empiric therapy is indicated, amoxicillin–clavulanate is the recommended first-line treatment because this combination is active against most of the pathogens that can be isolated from bite wounds. Penicillin and ampicillin are effective against Pasteurella species, but they should not be used alone without a beta-lactamase inhibitor, such as clavulanate, because Staphylococcus species and most of the anaerobic bacilli that may cause infections produce beta-lactamase. In more-severe cases, or if a patient is unable to take oral antibiotics, intravenous ampicillin–sulbactam can be considered.

In patients with serious beta-lactam allergy, as in this case, trimethoprim–sulfamethoxazole can be used for Pasteurella coverage. However, this agent alone is not sufficient for prophylaxis or treatment of infected animal bites because it does not adequately cover Streptococcus or anaerobes; thus, clindamycin should also be added.

A tetanus toxoid booster, together with human tetanus immune globulin, is recommended for children who have received fewer than three doses of the vaccine. Tetanus prophylaxis is not necessary for adequately vaccinated children unless the wound is dirty and the last tetanus dose was given 5 or more years ago, in which case a booster dose is recommended. When tetanus prophylaxis is indicated, it should be administered as soon as possible after a wound, even in patients who present late for medical attention.

In addition to providing antibiotic prophylaxis and assessing the need for tetanus prophylaxis, all animal bites should be evaluated for rabies risk. Local health departments can provide consultation about specific cases and give recommendations regarding the need for postexposure prophylaxis depending on the animal involved, the circumstances surrounding the bite, and the local epidemiology.

Last reviewed May 2020. Last modified Mar 2018.

Citations

Bula-Rudas FJ and Olcott JL. Human and animal bites. Pediatr Rev 2018 Oct; 39:490.   > View Abstract