What treatment should be given for a previously vaccinated patient with a dog lick wound on the knee, considering the risk of infection?

Dog Lick Wound Management in Previously Vaccinated Patient

For a previously vaccinated patient with a dog lick wound on the knee presenting more than 24 hours after exposure without signs of infection, do not prescribe prophylactic antibiotics. 1

Rabies Risk Assessment

Bite Category Classification

• A dog lick on intact skin or a healed wound is Category I exposure and requires no rabies post-exposure prophylaxis 2
• A dog lick on broken skin (abraded, scratched, or with an open wound) is Category II exposure 2
• For Category II exposure in a previously vaccinated patient, administer 2 doses of rabies vaccine only (on days 0 and 3), without rabies immunoglobulin 2
• Rabies immunoglobulin (HRIG) is not needed in previously vaccinated individuals, only vaccine boosters 2

Critical Rabies Decision Points

• If the dog is a domestic pet that can be observed, confine and observe the animal for 10 days 2
• A dog that remains healthy for 10 days after the exposure could not have been shedding rabies virus at the time of contact 2
• If the dog develops signs of illness during observation, immediately initiate post-exposure prophylaxis and euthanize the animal for testing 2
• For stray or unwanted dogs, either confine for observation or euthanize immediately for rabies testing 2

Antibiotic Management Algorithm

Timing-Based Decision

• If presenting within 24 hours: Consider prophylactic antibiotics only if high-risk features are present 1
• If presenting ≥24 hours without infection: Antibiotics are NOT indicated per World Society of Emergency Surgery guidelines 1
• The WSES explicitly recommends against prescribing antibiotics "just in case" at late presentation, as this violates guidelines and promotes resistance 1

High-Risk Features Requiring Antibiotics (if within 24 hours)

• Location: Hand, foot, face, genitals, or near joints 1, 3
• Wound characteristics: Deep wounds, puncture wounds, or significant tissue damage 1
• Patient factors: Immunocompromised status, diabetes, advanced liver disease, asplenia, prosthetic joints, or prosthetic heart valves 1

Note: The knee location alone does not constitute high-risk unless the wound penetrated the joint capsule 1

If Infection Develops

• First-line treatment: Amoxicillin-clavulanate 875/125 mg twice daily for 7-10 days 1, 3
• Alternative oral options: Doxycycline or moxifloxacin as monotherapy 1
• Dog bite wounds contain an average of 5 different bacteria, with Pasteurella species in 50%, Staphylococcus aureus in 40%, and Streptococcus species in 40% 1

Wound Care Protocol

Immediate Management

• Thoroughly irrigate with sterile normal saline or dilute povidone-iodine solution 3
• Remove superficial debris without enlarging the wound 3
• Do not use high-pressure irrigation, as it may drive bacteria into deeper tissue layers 2

Tetanus Prophylaxis

• Administer tetanus toxoid 0.5 mL IM if vaccination status is outdated or unknown 3

Critical Pitfalls to Avoid

• Never use first-generation cephalosporins, macrolides, or penicillinase-resistant penicillins alone if infection develops, as they have poor activity against Pasteurella multocida present in 50% of dog bites 1
• Do not prescribe antibiotics for late presentation (≥24 hours) without clinical signs of infection 1
• Be vigilant for Capnocytophaga canimorsus in patients with asplenia or liver disease, even from saliva exposure alone 1, 4
• Dog lick wounds have lower infection rates (5-25%) compared to cat bites (30-50%), but can still cause severe infections including septic shock in rare cases 1, 4

Monitoring Instructions

• Instruct the patient to return immediately if signs of infection develop: increasing redness, warmth, swelling, purulent drainage, fever, or systemic symptoms 1
• Elevate the knee if swelling develops to accelerate healing 3
• If the dog cannot be observed or develops illness, immediately contact local health officials for rabies risk assessment 2, 3