AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

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.

Mortality/Morbidity

• Many serious human bites occur during fist fights between older children.¹ 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. When the hand is extended, the contaminated tendon transfers the bacteria to a more proximal enclosed space. The patient may not immediately report this injury. Many times, the patient seeks medical care only after infection has developed.
• Saliva has not been implicated as a risk for the transmission of human immunodeficiency virus (HIV).
• 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

Section 3 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

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 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 usually can 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.

DIFFERENTIALS

Section 4 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Other Problems to be Considered

Cellulitis
Foreign body
Fracture
Insect bites

WORKUP

Section 5 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Lab Studies

• Wound culture may be indicated. Although laboratory studies are not needed for a noninfected bite wound, an infected wound should be cultured.
• A CBC count and an erythrocyte sedimentation rate (ESR) may aid evaluation of infections of more than a few days duration.
• Some infectious disease experts also use C-reactive protein (CRP) studies to monitor the course of infection.

Imaging Studies

• Radiography
• • Investigate the possibility of a foreign body or fracture following closed-fist bite wounds with radiographs of the hand.
  • The possibility of underlying osteomyelitis in an infection more than a few days duration mandates radiographic evaluation.
• Bone scanning: This may be considered upon negative radiography findings to rule out osteomyelitis.

Procedures

• Wound exploration is essential to evaluate the extent of damage to the affected area.
• Wound cleansing is essential. Wounds should be copiously irrigated with isotonic sodium chloride solution.

TREATMENT

Section 6 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical Care

• Tetanus vaccine should be administered as needed.
• Patients with infected wounds should be given antibiotics.
• Patients with closed-fist infected wounds should be admitted for intravenous antibiotics and for possible incision and drainage.
• Superficial wounds should be washed with soap and water.
• Deeper wounds should be irrigated with a copious volume of normal saline (NS).

Surgical Care

• Facial lacerations should be lavaged with isotonic sodium chloride solution and repaired primarily. Puncture wounds on the scalp or forehead should be closed secondarily as needed.
• Potentially disfiguring facial lacerations, especially those to the nose and ears, should be repaired by a plastic surgeon.
• Lacerations extending into the ear cartilage are at high risk for infection.

Consultations

• Human bite wounds involving the nose or ears often require plastic surgery or ear, nose, and throat (ENT) consultation.
• Bite wounds to the face associated with tissue loss should have a plastic surgery consultation.
• Closed-fist injuries often require consultation with a hand surgeon.
• Consultation with an infectious disease specialist may also be useful.

MEDICATION

Section 7 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Infection is the most feared complication of human bites. Studies have demonstrated that bite infections are polymicrobial, with an average of 5 microorganisms cultured per wound. Antibiotic coverage for Staphylococcus species and anaerobes is usually necessary. Amoxicillin and clavulanate is used most commonly. Penicillin-allergic patients may be treated with a combination of trimethoprim/sulfamethoxazole and clindamycin. Patients who tolerate cephalosporin may also be treated with ceftriaxone. Prophylaxis may also be provided with erythromycin or a tetracycline. A 3- to 7-day course of antibiotic commonly is used for prophylaxis.

Drug Category: Antibiotic agents

These agents are used for prophylaxis and for treatment of infection.

FOLLOW-UP

Section 8 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Further Inpatient Care

• The appropriate surgical subspecialties should be involved in the treatment of patients admitted to the hospital. Decisions to incise, drain, and explore tissue should be made after surgical consultation.
• Consider bone scanning, despite normal radiograph findings, if osteomyelitis is suspected.
• Appropriate dressings should be applied to bite wounds. Elevation of the affected extremity may be helpful.
• Pain should be treated with appropriate analgesics.

Further Outpatient Care

• Patients with significant closed-fist injuries without infection should be referred to a hand surgeon for reevaluation in 1-2 days.
• Wound checks on closed facial bites should be scheduled.
• Superficial bites need no follow-up.

Complications

• A primary concern with all deep bite wounds is infection.
• Most serious complications occur with human bites to the hand.

Patient Education

• For excellent patient education resources, visit eMedicine's Bites and Stings Center. Also, see eMedicine's patient education article Human Bites.

MISCELLANEOUS

Section 9 of 10  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

Medical/Legal Pitfalls

• Any initial disability should be documented. Failure to suspect and treat a bite wound may result in or exacerbate long-term disability.
• Failure to consider the possibility of an oral origin for puncture wounds to the head may lead to lack of treatment, inappropriate closure, and subsequent infection.
• Bite wounds may have abusive origin in younger children. Failure to report suspected abuse may allow a child to be returned to an abusive environment.
• Do not fail to consider bite wounds when evaluating injuries to the MCP area.
• Failure to obtain radiographs of MCP wounds may result in undiagnosed (open) fractures and a possible sequela of osteomyelitis.
• Glue should not be used on any bite wound.

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• References

1. Leung AK, Robson WL. Human bites in children. Pediatric Emergency Care. 1992;8(5):255-257. [Medline].
2. Baker MD, Moore SE. Human bites in children. A six-year experience. Am J Dis Child. Dec 1987;141(12):1285-90. [Medline].
3. CID. Report of the committee on infectious diseases. In: Red Book. 24^th ed. American Academy of Pediatrics; 1997:122-6.
4. Lindsey D, Christopher M, Hollenbach J, et al. Natural course of the human bite wound: Incidence of infection and complications in 434 bites and 803 lacerations in the same group of patients. J Trauma. 1987;27:45-48. [Medline].
5. Schweich P, Fleisher G. Human bites in children. Pediatr Emerg Care. Jun 1985;1(2):51-3. [Medline].

Article Last Updated: Dec 20, 2007