BITE WOUNDS
Bite wounds account for 1% of all emergency room visits, with an estimated 2 million bite wounds per year in the United States. Dogs account for 80 to 90% of all bite wounds. Cats are the next most common source of 5-15% of wounds. Human bites account for less than 5% of bite injuries. Although most bites are minor, they can result in major morbidity.

DOG BITES
In most cases, the victim knows the dog; the dog is often provoked. Children are more frequently bitten. Young dogs, and female dogs are more likely to bite. Most bites occur on the extremities, however in young children, bites are more likely to occur on the head and neck. Fatal dog bites are associated with the larger breeds and are most often due to exsangination from major neck vessels.

Dog bites become infected 2-20% of the time, one of the lowest rates for mammalian bites. Hand bites are at increased risk of infection, tenosynovitis and septic arthritis. Organisms found in the dog's oral cavity include Pasturella multicida, s. aureus, s. intermedius alpha-hemocytic strep, eikenella corrodens, and capnocytophaga canimorsus.

CAT BITES
Cat bites and scratches are more likely to become infected than dog bites. Because cat teeth are small and sharp, they can more easily penetrate joints and periosteum. Cat oral flora is similar to the dog's. Pasturella is the most common organism cultured from cat bites (50-70%).

HUMAN BITES
Most human bites occur during fights. Medical attention is frequently delayed. The clenched fist bite wound is the classic example. The patient punches someone with a clenched fist; the tooth punctures the patient's knuckle, driving organisms into the joint.

Human bites can cause serious infection. Strep Viridens, Staph aureus, Eikenella, Haemophilus influenza and oral anaerobes can be found.

TREATMENT
Important items in the history include the delay to treatment, tetanus immunization status, and the likelihood of rabies exposure. Patients who are immunocompromized are at higher risk for serious infection and should be treated more aggressively.

Physical exam should note the degree of contusion and crush because these wounds are more likely to become infected. Tendon and nerve involvements are indications for referral for possible surgical treatment. Joint penetration also is an indication for referral. If bone or joint damage is suspected, x-rays are indicated. Foreign bodies on x-ray may be tooth fragments, which should be removed.

All bite wounds should be thoroughly cleansed and debrided of devitalized tissue. Most dog bites can be safely closed if they are less than 8 hours old. Cat bites and human bites, because of their higher infection rates, are often left open. Puncture wounds are not closed. Human bites on the face or cosmetically important areas can be closed after proper debridement. Closure techniques are the same as other lacerations. The wound must be carefully followed for signs of infection.

Prophylactic antibiotic use is controversial. However, it is not mandatory for fresh uninfected dog bites. Cat and human bites are usually treated prophylactically. The drug of choice of all of these bites is amoxicillin / clavulanic acid. In penicillin allergic patients, choices include doxycycline (contraindicated in children and pregnant women) and ciprofloxacin. For established infections, empiric treatment may be started with one of these drugs. Cultures should be taken, with treatment based on the results.