• Patients with extensive trauma and/or arterial injury should be placed in a trauma bay with an appropriate trauma approach.
• If the injury is isolated and non-arterial, an ambulatory zone is usually adequate.
• If arterial injury is suspected, consult vascular surgery.

• The most prevalent mammalian bites in North America are from cats and dogs.
• Cats create deep puncture wounds that increase the risk of bacterial trapping and infection.
• Dogs often bite and shake their victim causing a “hole and tear” injury.
• Treatment recommendations are mostly based on historical dogma. Controversy remains on primary closure.
• Cat and dog bite wound infections are mostly polymicrobial. The most common bacteria include:
  • Pasteurella multocida
  • Capnocytophaga canimorsus
  • Fusobacterium
  • Bacteroides
  • Porphyromonas
  • Prevotella
  • Propionibacterium
  • Streptococci
  • Staphylococci
  • Moraxella
• Dog bite wound infections can also involve:
  • Neisseria
  • Corynebacterium
• C. animorsus acts as an encapsulated organism and can cause sepsis and DIC in immunocompromised patients, especially those with asplenia.
• The rate of wound infection from cat and dog bite are 10% to 40% and 6 to 16%, respectively. Infections include cellulitis, abscess, tenosynovitis, osteomyelitis (up to weeks later) and septic arthritis.
• Prophylactic antibiotics are not recommended universally, but all cat bites should be treated with antibiotics to cover Pasteurella.
• Risk factors for infection:
  • Wound
    • Devitalized tissue
    • Primary closure may increase rate of infection
  • Patient
    • Age over 50
    • Comorbid conditions resulting in immunocompromised status (e.g., cancer, diabetes, alcohol use disorder, etc.)
    • Asplenia

• Key historical elements include the patient’s tetanus status and whether the animal has had a rabies vaccination (in BC, rabies has only been reported in bats, although cats or dogs can acquire rabies from bat exposures.) See https://emergencycarebc.ca/clinical_resource/rabies-diagnosis-and-treatment/
• A focused physical exam, including an assessment for infection or trauma.
• Obtain XRs if there is a concern for fracture, joint injury, or retained foreign body (e.g., teeth.)
• Consider CT head in a young child with a scalp bite to evaluate for intracranial penetration.
• Blood work and wound cultures are generally not indicated.

Analgesia

Irrigation and debridement

• All bites require copious irrigation under pressure and debridement under local anesthesia. The only exemption is superficial cat bites, but not dog bites.

Wound closure

• Primary closure is controversial. The benefits (e.g., cosmesis) must be weighed against the risk of infection. Incorporate shared decision-making as appropriate. If closure is contraindicated, loose approximation using adhesive strips can improve cosmesis.
• There is general consensus for closure of scalp bites from any mammal if less than 6 hours old.
• Closure is NOT recommended in:
  • All puncture or crush injuries.
  • Delayed presentation over 6-8 hours.
  • All wounds more than 24 hours old.
  • Bite wounds over hands, feet, and joints.
  • Cat or human bites (except on scalp.)
  • Bite wounds in immunocompromised patients.

Antibiotics

• Cat bites:
  • Antibiotic prophylaxis is indicated for ALL cat bites penetrating through the epidermis, regardless of location.
• Dog bites:
  • Antibiotic prophylaxis is NOT indicated in all dog bites.
  • Antibiotics are indicated for:
    • Bites to the hand or foot.
    • Deep puncture wounds.
    • Bites in or near a prosthetic joint.
    • Bites with significant tissue damage.

Antibiotics for cat and dog bites

Immunization

• Tetanus prophylaxis +/- tetanus immunoglobulin, if indicated.
• Rabies prophylaxis, if indicated.

• Injuries requiring reconstructive surgery and/or general anesthesia.
• Rapidly spreading skin and soft tissue infections.
• Bacteremia or sepsis.
• Osteomyelitis, septic arthritis, infectious tenosynovitis.
• Failed outpatient therapy.

• In exceptional cases of worsening patient status that cannot be managed by resources at the current care facility, transfer to another facility is warranted.

• Patients with uncomplicated bites can safely be discharged home with return precautions.

1. Maniscalco K, Edens MA. Animal Bites. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Jul 8]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK430852/

   
   

2. Kheiran A, Palial V, Rollett R, Wildin CJ, Chatterji U, Singh HP. Cat bite: an injury not to underestimate. J Plast Surg Hand Surg. 2019 Dec;53(6):341–6.

   
   

3. Kennedy SA, Stoll LE, Lauder AS. Human and other mammalian bite injuries of the hand: evaluation and management. J Am Acad Orthop Surg. 2015 Jan;23(1):47–57.

   
   

4. Wound Management Principles – ClinicalKey [Internet]. [cited 2023 Jul 8]. Available from: https://www.clinicalkey.com/#!/content/book/3-s2.0-B9780323757898000505?scrollTo=%23hl0000617