Prevention and Treatment of Dog Bites

Author: R. John Presutti
Date: April 15, 2001

Almost one half of all dog bites involve an animal owned by the victim's family or neighbors. A large percentage of dog bite victims are children. Although some breeds of dogs have been identified as being more aggressive than other breeds, any dog may attack when threatened. All dog bites carry a risk of infection, but immediate copious irrigation can significantly decrease that risk. Assessment for the risk of tetanus and rabies virus infection, and subsequent selection of prophylactic antibiotics, are essential in the management of dog bites. The dog bite injury should be documented with photographs and diagrams when appropriate. Family physicians should educate parents and children on ways to prevent dog bites. (Am Fam Physician 2001; 63:1567-72,1573-4.)

Each year approximately 4 million Americans are bitten by dogs, and about 800,000 of these persons (44 percent of whom are younger than 14 years) present for medical treatment.(1-3) More than one dozen fatalities related to dog bites occur each year in this country; most of these victims are children.(1,2) Although most dog bite attacks are not provoked,(3) there are several measures that adults and children can take to decrease the possibility of being bitten. Family physicians can educate parents and children on ways to prevent dog bites, but, when dog bites do occur, the physician must be knowledgeable about how to treat the bites effectively.

As of 1994, an estimated 34 million American households owned at least one dog, accounting for a canine population in the United States in excess of 55 million.(1,2,4) Most dogs never bite a human; however, under certain circumstances, any dog is capable of inflicting harm. The most common victims of dog bites are children, especially in incidents that prove fatal.(2,5-7) Almost one half of all reported cases of dog bites involve an animal owned by the victim's family or the victim's neighbors.(3) Most victims are involved in normal, nonprovoking activities before the dog attacks.(2) For example, neonatal deaths resulting from a dog bite most often involve a sleeping baby.(1,2)

Several dog breeds have been identified for their role in fatal dog bite attacks, including pit bull breeds, malamutes, chows, Rottweilers, huskies, German shepherds and wolf hybrids.(1,2,8) From 1979 to 1988, pit bull breeds accounted for more than 41 percent of dog bite-related fatalities, three times as many as German shepherds.(2)

Management of Dog Bites

INITIAL WOUND MANAGEMENT

After confirming that the victim is medically stable, physicians should begin a primary assessment by taking a history. Several medical conditions place a patient at high risk of wound and rabies virus infection from a dog bite (Table 1).(7) Information that can help determine the patient's risk of infection includes the time of the injury, whether the animal was provoked, and the general health, immunization status and current location of the animal.(7) In some locations, notification of animal control or local law enforcement may be necessary. Also, the patient's tetanus immunization status, current medications and allergies must be noted in the record.(7) During the physical examination, the measurement and classification of the wound (laceration, puncture, crushing or avulsion), and the range of motion of the affected and adjacent areas should be documented. Nerve, vascular and motor function, including pertinent negative findings, should be recorded. Diagrams and photographs are useful, especially in cases with irregular wounds or signs of infection,(9) and in cases that may involve litigation, such as a wound inflicted by an unleashed dog.(7)

Timely and copious irrigation with normal saline or Ringer's lactate solution may reduce the rate of infection markedly. Injection of the tissue with irrigant solution should be avoided, because this can spread the infection.(5,7) Necrotic or devitalized tissues should be removed, but care must be taken not to debride so much tissue as to cause problems with wound closure and appearance.(9) Baseline radiographs may be obtained, especially with puncture wounds near a joint or bone.(5)

The role of wound closure remains controversial. Puncture wounds, wounds that appear clinically infected and wounds more than 24 hours old may have a better outcome with delayed primary closure or healing by secondary intention.(5,6) Some physicians close wounds that are less than eight hours old and wounds located on the face.(5) The success of closing facial wounds can probably be attributed to the enhanced blood supply to the face and the lack of dependent edema.(5) Plastic surgery, general surgery or maxillofacial surgery may be necessary for deep wounds or those requiring significant debridement and closure. Cultures are usually not helpful unless the wound appears infected or is unresponsive to appropriate antibiotic therapy. When a culture is necessary, aerobic and anaerobic cultures should be obtained and observed for a minimum of seven to 10 days to allow for slow-growing pathogens.(7) Orthopedic consultation should be considered for wounds that directly involve joints or other bony structures.

ANTIBIOTIC TREATMENT

Only 15 to 20 percent of dog bite wounds become infected. Crush injuries, puncture wounds and hand wounds are more likely to become infected than scratches or tears.(9) Most infected dog bite wounds yield polymicrobial organisms.(8) Pasteurella multocida and Staphylococcus aureus are the most common aerobic organisms, occurring in 20 to 30 percent of infected dog bite wounds.(4,5) Other possible aerobic pathogens include Streptococcus species, Corynebacterium species, Eikenella corrodens and Capnocytophaga canimorsus (formerly known as DF-2).(5,7,8) Anaerobic organisms, including Bacteroides fragilis, Fusobacterium species and Veillonella parvula, have also been implicated in infected dog bites. One review article(8) identified 28 species of aerobic organisms and 12 species of anaerobic organisms isolated from dog bite wounds.

Treatment with prophylactic antibiotics for three to seven days is appropriate for dog bite wounds, unless the risk of infection is low or the wound is superficial.(4,5,7) If frank cellulitis is evident, a 10- to 14-day course of treatment is more appropriate.(9) Amoxicillin-clavulanate potassium (Augmentin) is the antibiotic of choice for a dog bite. For patients who are allergic to penicillin, doxycycline (Vibramycin) is an acceptable alternative, except for children younger than eight years and pregnant women. Erythromycin can also be used, but the risk of treatment failure is greater because of antimicrobial resistance.(7,10) Other acceptable combinations include clindamycin (Cleocin) and a fluoroquinolone in adults or clindamycin and trimethoprim-sulfamethoxazole (Bactrim, Septra) in children.(11) When compliance is a concern, daily intramuscular injections of ceftriaxone (Rocephin) are appropriate.(7)

Occasionally, outpatient treatment of infection fails and the patient needs to be hospitalized and treated intravenously with antibiotics. Reasons for hospitalization include systemic signs of infection; fever or chills; severe or rapidly spreading cellulitis or advancement of cellulitis past one joint; and involvement of a bone, joint, tendon or nerve.(5)

Consultation with a maxillofacial or plastic surgeon may be required if the patient has a facial or other highly visible wound. For patients hospitalized with cellulitis or abscess formation in an extremity, surgical consultation should be considered immediately because of the risk of worsening infection and tissue damage. Depending on community practices and the location of the injury, general orthopedic surgery, hand surgery or general surgery consultation may be appropriate. Tetanus immunization and tetanus immune globulin should be administered, if appropriate. Recommendations for tetanus prophylaxis are given in Table 2.(12)

Measures for preventing dog bites are given in Table 5.(2) Dogs have a tendency to chase a moving object. Therefore, children need to learn to avoid running and screaming in the presence of a dog. Dogs should not be greeted by presenting an outstretched hand. Do not pet a dog without letting it sniff you first. Hugging and "kissing" a dog express a sense of submission to the animal, which is confusing because the animal is used to viewing humans as being in charge.(4) This confusion may lead to more aggressive behavior by the animal.

TABLE 5

Measures for Preventing Dog Bites

Never approach an unfamiliar dog.

Never run from a dog or scream in the presence of a dog.

Be still, "like a tree," when approached by a dog.

If knocked down, become "like a log."

Children should never play with a dog without an adult present.

Immediately report stray dogs or dogs with unusual behavior.

Avoid direct eye contact with a dog.

Do not disturb a dog that is eating, sleeping or caring for puppies.

Do not pet a dog without letting it first sniff you.

Tell children to report a dog bite to an adult immediately.

Information from Sacks JJ, Lockwood R, Hornreich J, Sattin RW. Fatal dog attacks, 1989-1994. Pediatrics 1996;97:891-5.

Educate children and adults to remain calm when threatened by a dog. Direct eye contact should be avoided because the dog may interpret that as aggression. Standing still ("like a tree") with feet together, fists folded under the neck, and arms placed against the chest is recommended. If knocked to the ground by a dog, recommendations include lying face down and becoming still "like a log," with legs together and fists behind the neck with forearms covering the ears. If a dog perceives no movement, it will lose interest and go away.

REFERENCES

(1.) Dog-bite-related fatalities--United States, 1995-1996. MMWR Morb Mortal Wkly Rep 1997; 46:463-7.

(2.) Sacks JJ, Lockwood R, Hornreich J, Sattin RW. Fatal dog attacks, 1989-1994. Pediatrics 1996;97:891-5.

(3.) Ndon JA, Jach GJ, Wehrenberg WB. Incidence of dog bites in Milwaukee, Wis. Wis Med J 1996; 95:237-41.

(4.) Iazzetti L. Anticipatory guidance: having a dog in the family. J Pediatr Health Care 1998;12:73-9.

(5.) Goldstein EJ. Bite wounds and infection. Clin Infect Dis 1992;14:633-8.

(6.) Anderson CR. Animal bites. Guidelines to current management. Postgrad Med 1992;92:134-6, 139-46,149.

(7.) Lewis KT, Stiles M. Management of cat and dog bites. Am Fam Physician 1995;52:479-85,489-90.

(8.) Griego RD, Rosen T, Orengo IF, Wolf JE. Dog, cat, and human bites: a review. J Am Acad Dermatol 1995;33:1019-29.

(9.) Presutti RJ. Bite wounds. Early treatment and prophylaxis against infectious complications. Postgrad Med 1997;101:243-4,246-52,254.

(10.) Talan DA, Citron DM, Abrahamian FM, Moran GJ, Goldstein EJ. Bacteriologic analysis of infected dog and cat bites. Emergency Medicine Animal Bite Infection Study Group. N Engl J Med 1999;340:85-92.

(11.) Human rabies--Washington, D.C., 1995. MMWR Morb Mortal Wkly Rep 1995;44:625-7.

(12.) Diphtheria, tetanus, and pertussis: recommendations for vaccine use and

other preventive measures. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 1991;40(RR-10):1-28.

(13.) Gilbert DN, Moellering RC Jr, Sande MA. The Sanford guide to antimicrobial therapy. 28th ed. Hyde Park, VT: Antimicrobial Therapy, 1998:36.

(14.) Human rabies prevention--United States, 1999. Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 1999;48 (RR-1):1-21 [Published erratum appears in MMWR Morb Mortal Wkly Rep 1999;48:16].

(15.) Dreesen DW, Hanlon CA. Current recommendations for the prophylaxis and treatment of rabies. Drugs 1998;56:801-9.

(16.) Bradshaw JW, Goodwin D, Lea AM, Whitehead SL. A survey of the behavioural characteristics of pure-bred dogs in the United Kingdom. Vet Rec 1996;138:465-8.

R. JOHN PRESUTTI, D.O., is a consultant and associate program director in the Department of Family Medicine at Mayo Clinic Jacksonville, Jacksonville, Fla. Dr. Presutti is also an assistant professor of Family Medicine at Mayo Medical School, Rochester, Minn. Dr. Presutti received his osteopathic medical degree from Nova Southeastern University, Fort Lauderdale, Fla., and completed a residency in family medicine at Mayo Clinic Jacksonville. He is a diplomate in family medicine and osteopathic family medicine.

Address correspondence to R. John Presutti, D.O., Mayo Clinic Jacksonville, 4500 San Pablo Rd., Jacksonville, FL 32224. Reprints are not available from the author.

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