Animal Bites to the Head and Neck

Although the risk of infection exists in any bite situation and proper wound management is required, animal bites to the head and neck require special considerations. The intimate juxtaposition of vital structures and the cosmetic issues of the head and neck region warrant special care for animal bite wounds to these areas.

Frequency

United States

Animal bites account for 1% of the emergency department visits in the United States. Up to 4.5 million people are treated for animal bites each year, and children and adults in the United States together suffer an estimated 400,000 cat bites and 4.5 million dog bites, annually.[4]

Using the Nationwide Emergency Department Sample, however, Holzer et al determined that between 2010 and 2014, the United States saw a reduction in the overall prevalence of dog bite injuries.[5]

Dixon and Mistry noted that after institution of a statewide stay-at-home order as a result of the coronavirus disease 2019 (COVID-19) pandemic, the rate of dog bite–related visits to the pediatric emergency department of their Colorado children’s hospital nearly tripled. Subsequent to relaxation of the restrictions, the investigators reported, the rate of such visits remained high.[6]

International

In studies from England and Scotland, animal bite injuries account for 3% of emergency department visits. In Switzerland, up to 23,000 people are treated for animal bites and scratches annually.

Mortality/Morbidity

Animal bites can lead to infection. Approximately 20% of dog bites in children become infected; the rate of infection of cat bites in children varies, but can reach 50%.[4] This consequence can be avoided, however, with appropriate treatment.

Other animal bite complications include sepsis, osteomyelitis, septic arthritis, and even death. Fatalities are uncommon, but an average of 10-15 deaths occur following dog bites each year in the United States. Most of these fatalities are children who sustain bites to the head and neck region. Even a minor bite to a major vessel can lead to hemorrhage in a small child. Skull fractures resulting from dog bites have been reported.

A study by Garvey et al of morbidity in pediatric dog bites, using data from a level one pediatric trauma center, found that 69% of patients required surgery. According to the report, which involved 282 pediatric patients (median age 5 years), surgical procedures included laceration repairs (76%), tissue transfers (14%), and neurosurgical operations (2%), with the most severe traumas consisting of laryngotracheal transection, intracranial hemorrhage, depressed skull fracture, and bilateral orchiectomy. No deaths occurred among the study’s patients.[7]

A Swiss study of dog bites indicated that wounds to the hand are at particular risk of developing secondary infectious complications. This may relate to the proximity of bradytrophic tissue, such as the tendons, to the surface of the skin, and a lack of natural anatomic barriers in the hand, which allows infection to spread.[8]

A prospective, multicenter, observational study by Tabaka et al indicated that among patients with dog bite wounds, those with puncture wounds or wounds that are closed during treatment have a high infection risk and should be considered for prophylactic antibiotic therapy. The study involved 345 dog bite patients, 18 of whom (5.2%) developed wound infections.[9]

A study by Babovic et al of 193 patients who had suffered a cat bite injury indicated that risk factors for hospitalization following a cat bite include the following[10] :

• Smoking

• Immunocompromised state

• Wound location over a joint or tendon sheath

• Erythema and swelling at presentation

The investigators did not find evidence that the length of time between bite and presentation affected the likelihood of hospitalization. They also found no link between hospitalization and the patient’s white blood cell count, C-reactive protein values, and erythrocyte sedimentation rate.[10]

Race

Epidemiologic data have failed to demonstrate an association between race and bites.

Sex

In general, animal bites occur with equal incidence in men and women. However, dog bites occur more frequently in men and boys, while cat bites occur more frequently in women and girls. The aforementioned study by Holzer et al found the likelihood of presenting with a dog bite to be particularly high among males diagnosed with an externalizing behavior disorder.[5]

Age

Animal bites occur more frequently in adults. However, children have a higher percentage of head and neck bites. Additionally, bites in children are more likely to warrant medical attention.

In a retrospective study of dog bites in the United States, Tam et al found that of pediatric patients (those aged 12 years or younger) admitted to a hospital with dog bites between 2015 and 2017, 78.1% and 4.8% had facial injuries or facial fractures, respectively, compared with 29.3% and 2.5%, respectively, of older patients. The rate of facial bone surgical procedures in the younger patients was 1.3%, versus 0.5% in those aged 13 years or older.[11]

The breed of the dog has been reported for some bites. Most bites (>50%) are inflicted by working dogs, which includes German shepherds, Doberman pinschers, collies, Great Danes, huskies, and mixed shepherd-type dogs. Sporting dogs, such as spaniels, retrievers, pointers, and setters, are implicated less frequently. Cats are not typically identified by breed.

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• Although the incidence of infection transmission is quite low, the risk of rabies is probably the best reason for investigating animal bite injuries. Regardless, many animal bites remain unreported because they are minor and can be self-treated.

• When evaluating a patient following an animal bite, the nature of the injury is pertinent, including whether or not the animal was known to the victim. The time of injury may have implications for treating potential wound infections or for addressing avulsed appendages.

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• Following an animal bite, patients require a full physical examination to address all bite wounds.

• Adults are injured most often in the extremities. Children are injured more often in the head and neck region compared with adults.

• The degree of injury is important. Some patients can be managed with local wound care or simple suturing by emergency department staff. Others require a consultation with a specialist or a trip to the operating room to address their wounds.

Epidemiologic studies have shown that most dog and cat bites are not from stray animals. Rather, the animal is often the pet of the victim or an acquaintance of the victim. In many animal bites in children, the animal was inadvertently provoked by the child. Infant swings have been linked to dog attacks.[12]

A prospective study by Touré indicated that risk factors for dog bites to the face include young age, a single-parent environment, and the presence of a German shepherd–type dog. In the study, which included 108 facial dog-bite patients, 68.5% of victims were under age 16 years, with 33.3% of them aged 2-5 years; 91.3% of bites took place in a single-parent environment.[13]

A study by Parent et al indicated that risk factors for dog bite–related craniofacial fractures in children include dog weight of greater than 30 pounds (odds ratio [OR] 19.6), Caucasian race (OR 7.3), presence of child on the floor (OR 6.2), age under 5 years (OR 4.1), and rural location (odds ratio [OR] 3.9).[14]

A study by Rezac et al indicated that human behaviors that increase the risk of dog bites to the face include bending over a dog and putting one’s face near a dog’s face (76% and 19% of cases, respectively). Gazing between humans and dogs also increased the risk (5% of cases). In the study, which involved 132 cases, more than two thirds of those bitten were children.[15]

Routine laboratory studies are not mandatory in the workup following an animal bite. However, with the risk of infection or sepsis, a complete blood count and cultures may provide useful information for treatment.

Imaging studies are not routinely performed, except for possible fractures. An imaging study may be helpful in identifying the presence of a foreign body (eg, a tooth).

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• Thorough cleansing is adequate for contused, intact skin. If the skin is penetrated, copious irrigation is warranted. Debridement is then required to remove any devitalized tissues resulting from the crush injury of the bite.

• In children, primary immediate closure of facial dog bite injuries with antibiotic coverage is suggested.[3]

• Special consideration is given to injuries to the head and neck region because of their close proximity of vital structures and the importance of cosmesis in this region. Consultation with a specialist may be required.

• Basic wound management is the sine qua non of therapy for animal bites. Treatment may include debridement, antibiotic therapy, supportive care, and, possibly, primary suturing or hospitalization with operative debridement. Of all bite injuries, 1-3% require hospitalization for surgical debridement and intravenous antibiotics. Clearly, wound severity dictates surgical management.

• Tetanus toxoid is administered, and the rabies status of the animal is investigated. In the event of possible rabies exposure, human diploid vaccine can be administered.

• Wounds can be classified as abrasions, lacerations, punctures, and avulsions. In the head and neck region, avulsions of special appendages are of particular concern, with the lip being the most common site of injury.

• The bite of a dog can yield between 150-450 pounds of pressure per square inch, depending on the dog and its training. Therefore, although a dog bite may appear as a laceration or avulsion, it most likely has components of a crush injury. Therefore, in this type of injury, debridement is required to remove any crushed tissues. Once débrided, the laceration injury is then amenable to suturing and primary closure.

• The force of a domestic cat's bite does not match that of a dog. However, its sharp teeth may cause a puncture wound into which bacterial organisms are inoculated. The risk of infection is compounded by the feline habit of paw licking, which may contaminate their claws with oral flora. The risk of infection is higher following a cat bite than a dog bite. Also, cat bites carry the risk of causing catscratch fever with resultant adenopathy. However, this is usually self-limited.

• Signs of infections are typical and include rubor, dolor, calor, and edema of the tissues. Purulent discharge from the wound is another good indicator of infection. Signs of infections may appear 24-72 hours following the bite. Obtain wound cultures to guide antibiotic therapy. Blood cultures are necessary if signs of a systemic infection are present. Drain any collections.

• Initial wound care mandates vigorous cleansing. This is accomplished easily with copious saline lavage under pressure. Puncture wounds also require copious lavage. Irrigation with povidone-iodine solution (Betadine) also may have an antiseptic effect.

Laceration injuries can be closed primarily, but avulsion injuries may benefit from delayed treatment. Injuries with significant tissue loss may require local flap treatment, composite grafts, or even vascularized flaps. Debridement of devitalized tissues in the head and neck region must be performed with care.

A study by Gurunluoglu et al indicated that the optimal treatment of facial dog bites requires that level-I trauma centers have a plastic surgery service available. In a study of 75 patients whose facial dog bite injuries who were treated only by a plastic surgery service (with 60 of 98 total wounds being treated by direct repair), the investigators reported that good outcomes were achieved by direct repair and reconstruction of these injuries as early as possible, with a low complication rate and a high rate of patient satisfaction achieved.[16]

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• Injuries to the head and neck region can be especially complex.

• Involvement of vital structures may require consultation with a head and neck surgeon.

• Because of cosmesis issues, consultation with a facial plastic surgeon may be required to ensure proper closure of a complex bite, to a repair fracture, or for reconstruction.

Injuries to the head and neck region have a lower risk of infection than injuries to the extremities. The risk of infection is increased with puncture wounds, treatment delay (6-12 h), and in patients older than 50 years. Likewise, patients who are immunocompromised are at increased risk.

The most common organisms are Staphylococcus species, Streptococcus species, Pasteurella multocida, and anaerobic organisms. No single drug of choice exists for empiric therapy (ie, no single drug targets all these organisms).

Class Summary

Therapy must be comprehensive and cover all likely pathogens in the context of this clinical setting.

Amoxicillin and clavulanate (Augmentin)

Drug combination treats bacteria resistant to beta-lactam antibiotics.

In children >3 mo, base dosing protocol on amoxicillin content. Due to different amoxicillin/clavulanic acid ratios in 250-mg tab (250/125) vs 250-mg chewable tab (250/62.5), do not use 250-mg tab until child weighs >40 kg.

Penicillin (Beepen-VK, Pfizerpen)

Inhibits biosynthesis of cell wall mucopeptide. Bactericidal against sensitive organisms when adequate concentrations are reached. Most effective during stage of active multiplication. Inadequate concentrations may produce only bacteriostatic effects.

Class Summary

These agents are used to induce active immunity against tetanus in selected patients.

Tetanus toxoid adsorbed or fluid

Immunizing agent of choice for most adults and children > 7 y is tetanus and diphtheria toxoids. Necessary to administer booster doses to maintain tetanus immunity throughout life. Pregnant patients should receive only tetanus toxoid, not a diphtheria antigen–containing product.

In children and adults, may administer into deltoid or midlateral thigh muscles. In infants, preferred site of administration is the mid thigh laterally.

Class Summary

In the event of possible rabies exposure, human diploid vaccine can be administered.

Rabies virus vaccine (Imovax, RabAvert)

Inactivated form of virus grown in primary cultures of chicken fibroblasts. Offers active immunity and, when used in combination with human rabies immune globulin and local wound treatment, protects postexposure patients of all age groups. Fourteen days after initiating immunization series, antirabies antibody titers reach levels well above minimal protective level of 0.5 IU/mL.

Vaccine must be injected IM and never SC, ID, or IV. In adults, inject into deltoid muscle area. In small children, administer into anterolateral zone of thigh.

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• Patients who are treated and released are advised to return for consultation in the event of local infection or sepsis.

• Patients treated with suturing require follow-up for removal of sutures and wound care, and some patients may be monitored on an outpatient basis for local wound care.

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• For most animal bites, local wound care with thorough cleansing and perhaps suturing of wound edges may be adequate treatment. Not all authors recommend the routine use of antibiotics following these treatments. However, in the event of more extensive injury or the development of infection, hospitalization may be required.

• With larger animal bites, bedside debridement may not be adequate. In situations with large amounts of tissue loss or an avulsed appendage, surgical debridement of the wound with immediate reconstruction or salvage of an appendage may be required.

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• The routine use of antibiotics for all bite wounds has not been established.

• Often, persons treated on an outpatient basis are given an oral antibiotic, especially with puncture wounds or wounds that require debridement and suturing.

• Patients who are admitted and patients who are septic require intravenous antibiotics. Analgesics are prescribed as necessary.

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• If an injury is extensive and has resulted in the loss of a significant amount of tissue or an appendage, the patient may be transferred to a tertiary care referral center. There, a patient can be treated with a vascularized free flap or replantation of the appendage.

With regard to the prevention of animal bites, the following should be kept in mind:

• Exposure to animals is clearly a risk

• The best preventative strategy is to avoid aggressive behavior with animals and avoid unfamiliar animals

• Teaching young children to avoid unnecessary provocation of animals may lead to fewer incidents of animal bites

• Not leaving children unattended in the presence of animals may also prevent attacks

A literature review by Duncan-Sutherland et al indicated that the rate of dog bites can be reduced through dog-control legislation, including leash laws and legislation aimed at stray dog control. Breed-specific legislation, however, was found to be less effective. Research also indicated that, by reducing the canine population, sterilization can lead to a decrease in dog bites, but whether this measure impacts dog aggression was not clear. In addition, it was suggested that intensive adult-directed education (but not child-directed education) can lead to a reduction. Moreover, one study found that the dog bite rate significantly declined in association with an alcohol reduction program.[17]

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• Complications can be considered immediate or delayed.

• Immediate complications include loss of appendage or disfigurement, which may warrant more extensive reconstruction later. Otherwise, infection is the most common complication of animal bites, which may prompt patients who were previously untreated or self-treated to seek treatment for their injuries.

• Additional complications associated with infection (eg, sepsis, osteomyelitis, septic arthritis) must be avoided or treated appropriately.

Animal bites lead to few fatalities, and most bites are not treated. Even in complicated cases with extensive tissue loss or infection, the prognosis is generally excellent.

Education is the key to prevention. This is pertinent, especially for children, who are at higher risk for a more serious bite injury. Children can be educated at a young age to avoid strange animals and to avoid aggravating familiar animals.

The small size of children puts them at risk for aggressive, dominating behavior by animals.