What are the treatment guidelines for a patient presenting with a dog bite in Canada, considering tetanus shot status, risk of rabies transmission, and potential antibiotic prophylaxis?

Dog Bite Management in Canada

Immediate Wound Care

All dog bite wounds require immediate and thorough irrigation with soap and water or sterile normal saline, as this single intervention markedly reduces the risk of both bacterial infection and rabies transmission. 1

• Use copious irrigation with a 20-mL or larger syringe to adequately cleanse the wound 2
• Perform cautious debridement of devitalized tissue only, avoiding enlargement of the wound that could impair closure 1
• Avoid deep or aggressive debridement that damages viable tissue, particularly on the face where cosmetic outcomes are critical 2

Tetanus Prophylaxis

Administer tetanus toxoid (0.5 mL intramuscularly) if the patient's vaccination status is not current within the past 5 years for contaminated wounds like dog bites. 1, 2

• If tetanus status is unknown or outdated, give Tdap (preferred over Td if not previously administered) 2
• This is a mandatory component of bite wound management regardless of other interventions 1

Rabies Risk Assessment and Prophylaxis

Contact your local public health department immediately to determine if rabies post-exposure prophylaxis is indicated, as this decision depends on the dog's vaccination status, observation availability, and local rabies epidemiology. 1

When Rabies Prophylaxis is Required:

• For previously unvaccinated patients exposed to a potentially rabid animal, administer both rabies immunoglobulin (HRIG) 20 IU/kg and rabies vaccine as a 5-dose series on days 0,3,7,14, and 28. 1
• Infiltrate as much HRIG as anatomically feasible into and around the wound, with remaining volume given intramuscularly in the gluteal area 1
• HRIG can be given up to day 7 after the first vaccine dose if not initially administered 1
• For previously vaccinated individuals (complete pre- or post-exposure series), give vaccine only without HRIG 1

Dog Observation Protocol:

• A healthy dog that bites should be confined and observed for 10 days without administering rabies vaccine during observation 1
• If the dog develops signs of illness during confinement, immediately notify public health and consider euthanasia with head submission for rabies testing 1
• Stray or unwanted dogs may be euthanized immediately for rabies examination 1

Antibiotic Prophylaxis

Prophylactic antibiotics should be initiated for high-risk wounds, including: puncture wounds, hand/foot bites, facial bites, wounds requiring primary closure, moderate-to-severe injuries, and bites in immunocompromised or asplenic patients. 1, 2, 3

First-Line Antibiotic Therapy:

• Amoxicillin-clavulanate 875/125 mg twice daily for 3-5 days is the preferred antibiotic, providing coverage against Pasteurella multocida (present in 50% of dog bites), Staphylococcus aureus, Streptococcus species, and anaerobes. 1, 2

Alternative Regimens for Penicillin Allergy:

• Doxycycline 100 mg twice daily (excellent activity against P. multocida) 2
• Moxifloxacin or other fluoroquinolones (ciprofloxacin, levofloxacin) may require additional anaerobic coverage 1, 4

Antibiotics to Avoid:

• Do not use first-generation cephalosporins, macrolides, or clindamycin alone—these have poor activity against P. multocida, the most common pathogen in dog bites. 2

Wound Closure Decisions

Facial Wounds (Special Exception):

Facial dog bite wounds should receive primary closure after thorough irrigation and debridement, ideally within 12-24 hours, due to the rich vascular supply that reduces infection risk and the critical importance of cosmetic outcomes. 1, 2, 4

• This is an explicit exception to the general rule against closing bite wounds 2
• Primary closure must be accompanied by prophylactic antibiotics 2, 4
• If discharge or infection is already present, do not close until infection is controlled 2

Non-Facial Wounds:

• Infected wounds should never be closed; use delayed primary or secondary closure instead. 1
• Early suturing (<8 hours after injury) of non-facial wounds is controversial with no clear guidelines 1
• Consider approximation with Steri-Strips rather than sutures for non-facial wounds 1
• Avoid suturing when possible to reduce infection risk 1

Management of Established Infection

If signs of infection develop (increasing pain, redness, swelling, purulent discharge), extend antibiotic therapy to 2-4 weeks and evaluate for complications. 2

• Pain disproportionate to injury near bone or joint suggests periosteal penetration, osteomyelitis, or septic arthritis 1
• Osteomyelitis requires 4-6 weeks of antibiotics 1
• Septic arthritis requires 3-4 weeks of antibiotics 1
• Hand wounds are particularly high-risk and often more serious than wounds to other body areas 1

Follow-Up and Monitoring

• Arrange follow-up within 24 hours either by phone or office visit for all bite wounds. 1
• Elevate the injured area using passive methods (sling for outpatients) to reduce swelling 1, 2
• If infection progresses despite appropriate therapy, hospitalize the patient 1
• Watch for rare but serious complications like Capnocytophaga canimorsus sepsis, especially in asplenic or immunocompromised patients 1, 5

Public Health Notification

Document and report dog bites to local public health authorities or police as indicated by local regulations. 6

• Canadian data shows public health notification is documented in only 19.5% of cases, representing a significant gap in care 6
• This is particularly important for severe bites, bites by unknown dogs, or when rabies risk exists 6

Common Pitfalls to Avoid

• Delaying wound irrigation—this is the single most important intervention and must be done immediately 1, 2
• Failing to assess tetanus status in every patient 1, 2
• Not consulting public health about rabies risk, particularly for stray or wild animal bites 1
• Using inadequate antibiotic coverage that misses P. multocida 2
• Closing infected wounds or non-facial wounds without careful consideration 1, 2
• Inadequate follow-up, particularly for hand wounds and puncture injuries 1
• Failing to provide or document preventive guidance to patients and families 6