Human Bites in Emergency Medicine Treatment & Management

• Recovery of avulsed tissue parts (eg, ear, finger) is an important consideration for prehospital providers. Otherwise, human bite wound management generally is uncomplicated and involves temporary dressing and transport.
• Avulsed parts should be wrapped in sterile gauze dressing that is soaked with normal saline and placed in a plastic bag that is, in turn, placed in a container of ice water.

The acute, noninfected human bite

• Cleanse and debride as usual
• Tetanus prophylaxis as indicated
• Antibiotic prophylaxis

  • The literature regarding prophylaxis of human bite wounds is sparse. Only 2 randomized controlled trials directly address the question. In the first, patients with acute, noninfected human bites to the hand were randomized to prophylaxis with placebo, an oral cephalosporin, or a parenteral cephalosporin plus penicillin. Bites involving joints or tendons were excluded from this study. The results were dramatic, with 47% of the placebo group developing infection, while none of the subjects treated with antibiotics developed infection.^[3]
  • A larger, more recent trial attempted to address the question in patients with "low-risk" human bites by randomizing them to placebo or an oral cephalosporin plus penicillin. This trial excluded patients with bites to the hands, feet, or cartilaginous structures, and no patient in this trial had a bite wound that penetrated deep to the epidermis. In this trial, no statistically significant difference was found in the placebo group compared to the group treated with antibiotics.^[4]
  • A large retrospective series examining human bite wounds in children found that none of the bites manifesting as abrasions became infected, while the rate of infection was much higher in bite wounds that caused punctures or lacerations.^[5]
  • From these data one can draw several conclusions:
    1. Acute human bites that do not penetrate the epidermal layer probably do not need antibiotic prophylaxis as long as they do not involve the hands, feet, joints, or cartilaginous structures.
    2. Human bites that completely penetrate the epidermal layer, as well as bites that involve joints or cartilaginous structures probably merit antibiotic prophylaxis, but the evidence is not strong.
    3. Human bites to the hand are at high risk for infection and probably should be given antibiotic prophylaxis.
• Injury patterns

  • Closed-fist injuries: An underlying fracture dictates inpatient treatment under certain circumstances. After appropriate anesthesia, explore the wound for joint space violation or tendon injury. Involvement of the joint space indicates admission. Consider patients with tendon injuries, which usually are present, for admission. Proper wound assessment includes using a tourniquet and extending the wound as needed to improve visualization. Provide outpatient treatment of these wounds (careful wound cleansing, antibiotic coverage, bulky dressing or splint, elevation) only in consultation with hand or orthopedic service. Early, mandatory follow-up care is essential.
  • Chomping injuries: Treat noninfected wounds that appear to violate the tendon apparatus in the same manner as noninfected closed-fist injuries.
  • Puncture wounds: These most commonly are encountered about the head. Such wounds are difficult to clean adequately unless extended to allow for effective irrigation. Even in the absence of infection, such wounds are best left open and closed secondarily, if cosmetically necessary.
  • Bites to the ear or nose: When associated with tissue loss, these wounds require consultation with plastic surgery or ear, nose, and throat (ENT) service. Seeking consult for a bite that violates cartilage in these areas also is prudent because of poor blood supply to cartilage and difficulties in treating chondritis.

The infected human bite wound

• The current recommendations from the Infectious Disease Society of America (IDSA) call for the use of amoxicillin/clavulanate or ampicillin/sulbactam. Cephalexin, which is commonly used for skin and soft-tissue infections, is ineffective against Eikenella corrodens, an important pathogen in infected human bites. TMP/SMX plus clindamycin is an acceptable alternative in the penicillin-allergic patient.^[6]
• Infected closed-fist injuries are a special case because of the deep nature of these infections and relatively poor vascular supply to the tendons and other connective tissue. Admitting patients for intravenous (IV) antibiotic therapy is generally considered appropriate is these cases. Surgical debridement and drainage also may be necessary.

Other considerations

• HIV transmission has been noted only rarely after a human bite. Exposure to saliva alone is not considered a risk factor for HIV (or hepatitis) transmission. Transmission requires HIV-infected blood mixed in the saliva of the biter and a skin break on the victim. The reverse consideration also is important in that blood drawn from an HIV-infected victim would come in contact with the mucous membranes of the biter. A 2005 Centers for Disease Control and Prevention recommendation states that postexposure prophylaxis with a 28-day course of highly active antiretroviral therapy (HAART) should be used in either of these 2 scenarios.^[7]

• In general, consult hand and/or orthopedic service for infected human bites of the hand and those involving a fracture, joint space violation, or significant tendon injury. Consider consultation or agreed-upon protocols for other human bites to the hand.
• Consult plastic surgery or ENT service for significant injuries to the special structures about the face and for wounds involving significant tissue loss.