Dog Bite


Dog Bite, Canine Bite

  • Epidemiology
  1. Worldwide, Dog Bites are the most common cause of Rabies
    1. Rabies is responsible for 59,000 deaths worldwide per year
  2. Incidence in United States: 4 to 4.5 Million bites per year
    1. Rate: 103-118 per 100,000 people in U.S.
    2. Over 330,000 Emergency Department visits per year
    3. Dog Bites account for 80-90% of Animal Bites in U.S.
    4. Unprovoked Dog Bites account for 50% of events
    5. Dogs are known to the victim in 70% of Dog Bite cases
  3. Mortality: >12 per year in U.S. (most are children)
    1. Pit bulls accounted for 44% fatalities 1979-1988
    2. Rottweilers are also responsible for many of the fatalities
  4. Infection rate: 15-20%
  5. Children are more likely than adults to sustain bites (esp. school age males)
    1. Preschool children are typically bitten by their family dogs at home
    2. Teens are typically bitten by dogs unknown to them outside the home
  • Risk Factors
  • Bites associated with breed
  1. Aggressive dogs
    1. Dogs associated with fatal attacks
      1. Pit Bull
      2. Malamute
      3. Chow-Chow
      4. Rottweiler
      5. Siberian Husky
      6. German Shepherd
      7. Wolf hybrids
    2. Other Aggressive dogs
      1. Bull terrier
      2. Cocker spaniel
      3. Collie
      4. Doberman Pinscher
      5. Great Dane
  2. Less aggressive breeds (Family dogs)
    1. Boxer
    2. Dalmatian
    3. English Setter
    4. English Springer
    5. Golden Retriever
    6. Irish Setter
    7. Labrador Retriever
    8. Spaniel
  • Pathophysiology
  1. Crush or avulsion injuries are more typical from Dog Bite
    1. Extensive Lacerations and soft tissue avulsions are most common
  2. Jaw of a dog can generate pressures up to 450 psi (some report up to 1800 psi)
    1. Occult Fractures may occur with high compression forces
  3. Foreign body risk
    1. Dog Bites may leave tooth fragments in wounds
    2. Carefully examine wounds and consider xray for Retained Foreign Body
  • Signs
  • Distribution
  1. Head and Neck (15% of Dog Bites)
    1. Typical site for Dog Bites in young children, especially ears
  2. Extremities (arms account for 60% of Dog Bites)
    1. Typical site for Dog Bites in adolescents and adults
    2. Perform a careful Hand Exam (esp. Hand Neurovascular Exam)
      1. Occult hand tendon injuries are common
  • Imaging
  1. Imaging is not routinely needed in most Dog Bites
  2. Extremity
    1. Consider XRay imaging in extensive, deep wounds to evaluate for Fractures and retained foreign bodies
  3. Head and Face
    1. Consider imaging if deformity identified
  • Management
  1. Update Tetanus Vaccination as needed
  2. Perform wound cleaning, copious Wound Irrigation, and foreign body and devitalized tissue Debridement
    1. See Animal Bite for irrigation and general management
  3. Antibiotics
    1. See Dog Bite Infection for antibiotic selection
  4. Confirm dog has up to date Vaccinations including Rabies
    1. Start Rabies Prophylaxis if Rabies status cannot be confirmed
    2. Alternatively, quarantine healthy dog and observe for 10 days
      1. Necropsy for Rabies if dog dies or shows signs of Rabies during 10 day observation
  5. Wound Repair
    1. Safe to repair all Dog Bite wounds (regardless of location) presenting within 8 hours of bite injury
      1. Infection rates increase significantly after 8 hours (22% infection rate versus 4.5%)
      2. Bite wounds treated with primary closure should be treated with antibiotics (see Dog Bite Infection)
    2. Inform patient of risks of infection, closure options
      1. Primary closure results in significantly better cosmetic results than secondary closure
      2. Dog Bite Infection rates are similar regardless of management
        1. Primary closure (6-9.7%)
        2. Secondary closure (6.9%)
    3. References
      1. Chen (2000) Acad Emerg Med 7(2): 157-61 [PubMed]
      2. Paschos (2014) Injury 45(1): 237-40 [PubMed]
  • Complications
  • General
  1. Significant morbidity and mortality worldwide (esp. children)
  2. Dog Bite Infection (see below)
  3. Retained tooth fragments
  4. Chronic Scars (50% of Dog Bites)
  5. Posttraumatic Stress Disorder
    1. Short-term Nightmares or avoidance is common (seek medical attention if they persist)
  6. Rabies
  7. Tetanus
  1. See Dog Bite Infection
  2. Complicates 15-20% of Dog Bites
  3. Pasteurella Canis most common infection (aerobic infection)
  4. Other common aerobic infections
    1. Staphylococcus
    2. Streptococcus
  5. Other common anaerobic infections
    1. Fusobacterium
    2. Bacteroides
    3. Prevotella
    4. Porphyromonas
    5. Propionibacterium
  • Disposition
  1. Outpatient Wound Check in 24-48 hours Indications
    1. Usually indicated over inpatient care
    2. All hand wounds should be rechecked
  • Prevention
  • Dog Bites
  1. Keep dogs updated on Vaccinations (and other routine veterinary care)
  2. Socialize dogs as puppies to children and strangers
  3. Neutered dogs are less likely to bite
  4. Trained dogs are less likely to bite out of fear
  5. Do not leave young children alone with a dog
  6. Exercise caution with ill pets or those in pain (more likely to bite)
  7. Do not approach an unknown dog without an owner's permission
  8. Use environmental barriers in and around the home (e.g. baby gates, fences)
  9. Keep dogs on a leash in public areas (outside of dog parks)
  • Prevention
  • Lessons for Children
  1. Do not approach an unfamiliar dog
  2. Do not disturb a dog eating or sleeping
  3. Do not disturb a dog caring for puppies
  4. When approached by a dog
    1. Never scream near a dog
    2. Never run from a dog
      1. Be still (Like a tree)
      2. If you fall, become a log
    3. Allow the dog to first sniff you before petting him
    4. Do not make direct eye contact with the dog
  5. Reporting guidelines
    1. Report Dog Bites to an adult immediately
    2. Report stray dogs or unusual behavior immediately
  • Resources
  1. Dog Bite Prevention (American Veterinary Medical Association)