II. Epidemiology

  1. Dog Bites: 4.5 Million/year in U.S. (80-90% of Animal Bites)
  2. Cat Bites: 400,000 per year in U.S. (5-10% of Animal Bites)
  3. Human Bites: 250,000 per year

III. Risk Factors: Bite site infection

  1. Vascular compromise in affected wound
    1. Peripheral Arterial Disease
    2. Venous Insufficiency
    3. Lymphedema
    4. Longstanding Tobacco Abuse
  2. Distal extremity wounds have diminished vascular supply (Hand bite, Foot Bite)
  3. Bite site near a prosthetic joint
  4. Crush injury or Puncture Wound
  5. Cat Bite (long slender fangs risk deep space infection)
  6. Delayed presentation
    1. Arm or leg bite site >6-12 hours
    2. Facial bite site >12-24 hours
  7. Diabetes Mellitus or other immunosuppressed state

IV. HIstory

  1. Injury
    1. Wound sites
    2. Active bleeding
    3. Pain
    4. Weakness
    5. Numbness
    6. Fever or other signs of infection
  2. Animal
    1. Type of animal
    2. Animal behavior (provoked attack, aggressive behavior)
    3. Immunization status of animal
    4. Can animal be observed (e.g. pet or captured)
    5. Pre-evaluation wound management
    6. Animal control or police involvement
  3. Medical History
    1. Tetanus Immunization status
    2. Prior Rabies Vaccination
    3. Immunocompromised status (e.g. Asplenia, Chemotherapy)

V. Exam

  1. See Hand Exam
  2. Perform thorough skin exam
    1. Map bite locations
    2. Record bite dimensions including depth
    3. Document wound types (punctures, Lacerations, crush injuries)
  3. Identify Pitfalls
    1. Some wounds may not be initially evident (especially in younger children)
      1. Scalp and skull may hide significant injury under hair, behind ears or in skin folds
    2. Retained Foreign Body
    3. Infectious signs (erythema, edema, Lymphadenopathy, drainage)
    4. Neurovascular injury
      1. Extremity pulses and Capillary Refill
      2. Motor and senory exam
      3. Compartment Syndrome
    5. Structural injury
      1. Tendon Injury
      2. Open Fracture
      3. Joint penetration
    6. Facial Injuries (esp. orbital and periorbital wounds)
      1. Risk of ocular injury
      2. Proptosis
      3. Visual changes
      4. Orbital Cellulitis (and risk of Meningitis, Encephalitis, Brain Abscess)
      5. Facial Erysipelas

VI. Imaging

  1. XRay affected bite site
    1. Evaluate for Retained Foreign Body (esp. Avulsed Teeth)
  2. Head Imaging (e.g. Head CT)
    1. May be indicated in severe bites to the head
    2. Penetrating skull bites can generate enough force for Skull Fracture (risk of CNS Infection, abscess)

VII. Management: General

  1. Control bleeding first
  2. Provide analgesia and Anesthesia
    1. See Pediatric Analgesic
    2. Acetaminophen or Ibuprofen
    3. Consider Intranasal Fentanyl in children
      1. Dose: 2 mcg/kg intranasal (1/2 in each nostril) via MAD Atomizer
    4. Inject 1% Lidocaine through intact skin
  3. Clean wounds with soap and water if not already performed at home
  4. Copious Wound Irrigation with Normal Saline (or continous tap water irrigation under faucet)
    1. Set up 1000 ml saline bag with 20 gauge angiocatheter (or 20 ml or larger syringe)
    2. Place bag into BP cuff and pump up to 300 mmHg
    3. Irrigate wound with 1000 cc of Normal Saline
      1. Consider irrigation with dilute Povidone-Iodine solution if the animal is suspected to be rabid
    4. Do not use excessive pressure (may drive risk of infection to deeper tissues)
  5. Wound closure
    1. Indications for closure by Secondary Intention
      1. Cat Bite
      2. Human Bite
      3. Livestock bites
      4. Monkey bites
      5. Puncture Wounds
      6. Highly contaminated wounds
      7. Infected wounds
      8. Wounds older than 24 hours
      9. Crush wounds with structural injury (urgent Consultation)
      10. Distal extremity wounds with poor perfusion
      11. Immunocompromised patients
    2. Indications for Sutured closure (primary closure)
      1. Wound less than 12 hours old on extremities
      2. Wounds located on face less than 24 hours old
      3. No serious underlying injury
      4. Scalp Wounds
    3. Technique
      1. See Laceration Repair
      2. Debride devitalized tissue
      3. Explore wound carefully for associated injuries and foreign body
      4. Perform single layer closure
        1. Do not place deep Sutures
        2. Do not use Tissue Adhesive
  6. Wounds near joint or bone
    1. Obtain baseline XRay of puncture
    2. Obtain Orthopedic Consultation
  7. Wound exploration
    1. Explore wound for tendon, joint or bone injury
    2. Explore wound for foreign bodies (e.g. teeth fragments, which may break off in older animals)
      1. XRay wound if suspected Radiopaque Foreign Body
  8. Subspecialty Referral Indications
    1. Wounds near bone or joint
    2. Crush wounds with structural injury (e.g. Fracture, tendon Laceration)
    3. Infected wounds
    4. Wounds with significant edema
    5. Neurovascular injury or compromise (emergent Consultation)
    6. Deep structure involvement (especially on the face, extremities, hands)
  9. Immunization
    1. Tetanus Vaccine
    2. Rabies Prophylaxis
      1. See Rabies Postexposure Prophylaxis for full list of indications
      2. Indicated if dog or cat with Unknown Vaccination status
        1. Unprovoked attack
        2. Animal cannot be quarantined for 10 days
          1. Do not euthanize animal prior to completion of 10 day observation
      3. Immediate wound management (see Rabies Prophylaxis)
      4. Start Vaccine within 48 hours
  10. Antibiotic Prophylaxis
    1. See Bite Wound Antibiotic Prophylaxis

VIII. Prevention

  1. See Dog Bite

X. References

  1. Cowling and House (2017) Crit Dec Emerg Med 31(5): 15-20
  2. Shivaprakash and Vezzetti (2022) Crit Dec Emerg Med 36(2): 3-10
  3. Ellis (2014) Am Fam Physician 90(4):239-43 [PubMed]

Images: Related links to external sites (from Bing)

Related Studies

Ontology: Animal bite (C0003044)

Definition (MEDLINEPLUS)

Wild animals usually avoid people. They might attack, however, if they feel threatened, are sick, or are protecting their young or territory. Attacks by pets are more common. Animal bites rarely are life-threatening, but if they become infected, you can develop serious medical problems.

To prevent animal bites and complications from bites

  • Never pet, handle, or feed unknown animals
  • Leave snakes alone
  • Watch your children closely around animals
  • Vaccinate your cats, ferrets, and dogs against rabies
  • Spay or neuter your dog to make it less aggressive
  • Get a tetanus booster if you have not had one recently
  • Wear boots and long pants when you are in areas with venomous snakes

If an animal bites you, clean the wound with soap and water as soon as possible. Get medical attention if necessary.

Centers for Disease Control and Prevention

Concepts Injury or Poisoning (T037)
ICD9 E906.5
SnomedCT 157939001, 217696009, 287171004, 31986002, 418975000
LNC LA17118-3
Spanish mordedura de un animal, mordedura de un animal (evento), Mordedura de animal NEOM, mordeduras de animales, SAI (hallazgo), mordeduras de animales, SAI (evento), Animal bites NOS, mordeduras de animales, SAI (trastorno), mordeduras de animales, SAI, mordedura de animal (anomalía morfológica), mordedura de animal, Mordedura de animal
Italian Morso di animale, Morso di animale NAS
Dutch dierlijke beet NAO, beet; dier, dier; beet, dierenbeet
French Morsure d'animal SAI, Morsure d'animal
German Tierbiss NNB, Tierbiss
Portuguese Mordedura de animal NE, Mordedura de animal
Japanese 動物咬傷NOS, 動物咬傷, ドウブツコウショウNOS, ドウブツコウショウ
English Animal bites NOS, Animal bite NOS, Animal bite, Bite;animal, animals bites, animal bites, Animal Bites, Animal bites NOS (disorder), Animal bites, Animal bites NOS (event), Animal bite (morphologic abnormality), bite; animal, animal; bite, Bite by unspecified animal, animal bite, Animal bites NOS (finding), Bite of animal (event), Bite of animal
Czech Kousnutí zvířetem, Kousnutí zvířetem NOS
Hungarian Állatharapás, Állatharapás k.m.n.

Ontology: Mammal bite wound (C0561547)

Concepts Injury or Poisoning (T037)
SnomedCT 283683002, 242606001
Spanish mordedura de un mamífero (evento), mordedura de un mamífero (hallazgo), mordedura de mamífero, herida por mordedura de mamífero (trastorno), herida por mordedura de mamífero, mordedura de mamífero (trastorno), mordedura de un mamífero
English Mammal bite, Bite of mammal, Mammal bite wound (disorder), Mammal bite wound, Mammal bite (disorder), Bite of mammal (finding), Bite of mammal (event)