eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease

Human Bites

Author: Clifford S Spanierman, MD, Consulting Staff, Departments of Emergency Medicine and Pediatrics, Lutheran General Hospital of Oak Brook, Advocate Health System
Contributor Information and Disclosures

Updated: May 29, 2009

Introduction

Background

Human bites are common in the pediatric age group. Bites may be inflicted during altercations, during play, or even by abusive adults. Bite wounds vary from superficial abrasions to severely disfiguring injuries. The most common complication of human bites is infection. Many concerned parents bring children (particularly younger children) with superficial bite wounds to medical personnel because of the fear of infectious disease transmission.

Pathophysiology

Bacteria heavily colonize the human mouth. Oral flora contains many potentially pathogenic aerobic and anaerobic bacteria. Among these bacteria are Staphylococcus, Streptococcus, Clostridium, and fusiform-shaped species. Bite wounds can inoculate the affected tissue with these microorganisms.

Bites cause varying amounts of tissue destruction. Tissue destruction from human bites tends to be less severe than that of dog bites. Nevertheless, human bites may be potentially disabling or life threatening.

Frequency

United States

Estimates vary regarding the frequency of human bites evaluated in US emergency departments (EDs). Some sources report an annual incidence of 250,000 human bites. This is well below the incidence of dog bites and is approximately half the incidence of cat bites. One study estimated that human bite wounds account for 0.1% of all ED visits.¹

Mortality/Morbidity

Many serious human bites occur during fist fights between older children.² Injury commonly occurs when a clenched fist strikes another individual's mouth and a tooth penetrates through the dermis of the knuckle into underlying connective tissue. Bacteria are inoculated into the metacarpophalangeal (MCP) joint.

Saliva has not been implicated as a risk for the transmission of human immunodeficiency virus (HIV). However, hepatitis B can be transmitted.

A primary concern with all deep bite wounds is infection. In the complex anatomy of the hand, infection spreads along the course of the tendon sheaths. Patients with hand infections from bite wounds may require admission, intravenous antibiotics, and wound incision and drainage. Infection may cause a permanent disability of the hand.

Sex

The frequency of bite wounds is higher in males than in females.

Age

Older boys and adolescents have a higher incidence of closed-fist injuries because of their more aggressive behavior. In younger children, boys may collide with each other while engaging in sports. This may lead to a puncture wound of the forehead, scalp, or ear caused by a high-speed head-to-head contact, with penetration of the above tissues by a tooth. Puncture wounds to the head may be deceptively deep.

Clinical

History

• Eliciting a history of a human bite may be difficult at times. Adolescents may be evasive in their explanations regarding a wound over the metacarpophalangeal (MCP) joint. Children may not know that they acquired a bite wound during a collision and may attribute a wound to blunt trauma. Recording the time of the injury is essential.
• Often a patient is not present for medical care until signs of a wound infection are manifest. A wound over the MCP joint space should elicit a high index of suspicion of a human bite.
• The potential diagnosis of a human bite should be entertained in children presenting with puncture wounds to the scalp or forehead.
• The diagnosis of abuse should be considered in younger children especially if preverbal. Report bite marks with inconsistent explanations from caretakers.
• Document the patient's immunological status.
• Document the patient's tetanus vaccination status.

Physical

• The physical examination should focus on depth of the wound, loss of tissue, presence of infection, and integrity of motor function.
• Small abrasions and scrapes can usually be managed with soap and water.
• Loss of tissue may be disfiguring. Areas with extensive destruction, such as the nose and ears, should be referred to a plastic surgeon.
• Injuries to the MCP joint should be explored. Consider the possibility of fracture or a foreign body (tooth fragment). Referring patients with MCP joint injury to a hand surgeon for evaluation may be prudent.
• Signs of infection in the hand warrant consultation with a hand surgeon, as well as intravenous antibiotics and admission.
• Wounds to the scalp and forehead may be deceptively deep and can involve deeper structures.
• Puncture wound have a higher risk of infection compared with lacerations. Lacerations tend to cause more tissue damage.

Causes

• Alcohol use may be a contributing factor.
• Abusive caretakers may bite younger children. Other injuries to the child, in addition to sexual abuse, should also be considered.
• Disturbed family dynamics characterized by violent interactions may increase the risk of bite wounds.

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