This chapter focuses on the clinical evaluation and management of wounds caused by bites from a variety of species, predominantly mammals. Treatment of infected bite wounds, as well as prophylaxis of selected uninfected bite wounds, will be covered.
Animal bites occur frequently in the United States, accounting for at least 1% of all visits to hospital emergency departments each year.1,2 Approximately, 80% of all bite wounds are minor in nature and do not require medical attention.3 Five to ten percent of bite wounds warrant suturing, and 2% require hospital admission. The overall morbidity of bite wounds, however, includes infectious complications, cosmetic complications, disability, psychological trauma, and medical expenses. Annual health care expenditure for the treatment of bite wounds is estimated to be between $30 million and $100 million.2–4
It is widely accepted that bite wounds are more common in children, especially those of age 5–9 years, and are more common in boys. School-aged children comprise 30–50% of all mammalian bite victims, while accounting for only 15% of the population.5 The number of reported bite wounds grossly underestimates the actual number of bites that occur each year. A survey of children aged 4–18 years revealed that 45% had been bitten by a dog during their lifetime, despite annual reported bite rates of 0.5% for children 5–14 years of age.6
The vast majority of mammalian bite wounds (80–90%) are inflicted by dogs. In 1994, an estimated 4.7 million dog bites occurred in the United States, necessitating close to 800,000 medical visits.7 Cat bites are second in frequency (5–10%) with an estimated 400,000 per year,8 followed by human bites (2–3% of mammalian bites). More than 70% of bites are caused by the victim's own pet or an animal known to them.2
Wounds caused by bites, or through accidental contact with teeth or fangs, can cause different types of tissue injury, most commonly abrasions and lacerations. Bite wounds that result in medical attention also include punctures, avulsion of soft tissue, crushing of tissue, fractures, and violation of normally sterile sites, such as joint spaces. The amount of pressure generated by dog bites is likely to produce localized crush injuries, with devitalized tissue that is prone to infection. Sixty percent of dog bite wounds are punctures, 10% are lacerations, and 30% are a combination of both. In contrast, 85% of cat bite wounds are punctures, 3% are lacerations, and 12% are a combination of both.9 Puncture wounds are harder to cleanse and irrigate, and thus have a high infection rate. Human bites are equally likely to produce lacerations, punctures, or a combination of both.10
Most mammalian bite wounds occur on the extremities, especially the hands and arms.1,7 In children younger than 5 years, a larger proportion (50–70%) of bite injuries occur to the face and head, especially those caused by ...