What is the recommended management for a Category III dog bite, including wound cleaning, rabies post‑exposure prophylaxis, tetanus update, and antibiotic prophylaxis?

Category III Dog Bite Management

For a Category III dog bite (transdermal bite or scratch with bleeding), immediately wash the wound with soap and water for 15 minutes, infiltrate human rabies immune globulin (HRIG) 20 IU/kg into and around all wounds, initiate a 4-dose rabies vaccine series (days 0,3,7,14) in the deltoid, update tetanus prophylaxis, and administer amoxicillin-clavulanate 875/125 mg twice daily for 3–5 days. 1, 2

Immediate Wound Care

• Wash all bite wounds thoroughly with soap and water for at least 15 minutes as soon as possible after the injury—this single intervention markedly reduces both bacterial infection risk and rabies transmission in animal studies. 1, 2

• After soap-and-water cleansing, irrigate the wound with povidone-iodine solution (or similar virucidal agent) using a ≥20 mL syringe to further reduce viral and bacterial load. 1, 2

• Avoid primary wound closure whenever possible, especially for puncture wounds, hand injuries, or heavily contaminated wounds, because suturing increases infection risk. 1, 2

• Examine the wound carefully for tendon or bone involvement, joint capsule penetration, or foreign bodies—these findings mandate surgical consultation. 1, 2

Rabies Post-Exposure Prophylaxis

Risk Assessment

• If the dog is a healthy domestic animal that can be confined and observed for 10 days, initiate wound care and antibiotics but defer rabies prophylaxis until the observation period is complete. 1, 2

• Initiate immediate rabies PEP if the dog is stray, unavailable for observation, dies or shows illness during the 10-day period, has unknown vaccination status, or if local epidemiology indicates high rabies risk. 1, 2

• Unprovoked attacks are more likely to indicate rabies than provoked attacks and should lower the threshold for immediate prophylaxis. 1, 3, 2

HRIG Administration (Previously Unvaccinated Persons)

• Administer HRIG at exactly 20 IU/kg body weight on day 0, ideally simultaneously with the first vaccine dose. 1, 2, 4

• Infiltrate the full calculated HRIG dose around and into all bite wounds whenever anatomically feasible; inject any remaining volume intramuscularly in the gluteal region at a site distant from vaccine administration. 1, 2, 4

• Never administer HRIG in the same syringe or at the same anatomical site as the vaccine, as this interferes with vaccine efficacy. 1, 2, 4

• Do not exceed 20 IU/kg—higher doses partially suppress the active antibody response generated by the vaccine. 1, 2, 4

• HRIG may be administered up to and including day 7 after the first vaccine dose if not given initially; beyond day 7, HRIG is contraindicated because vaccine-induced antibodies are presumed present. 1, 2, 4

Rabies Vaccine Series

• Administer 1.0 mL of rabies vaccine (HDCV or PCECV) intramuscularly on days 0,3,7, and 14 for previously unvaccinated immunocompetent persons. 1, 2, 4

• Inject in the deltoid muscle for adults and older children; use the anterolateral thigh for young children. 1, 2, 4

• Never use the gluteal area for vaccine administration—this produces inadequate antibody response and has been associated with vaccine failures. 1, 2, 4

• Day 0 is defined as the day the first dose is given, not necessarily the day of exposure. 1, 4

Special Populations

• Previously vaccinated persons (completed pre- or post-exposure series with cell-culture vaccine) require only 2 vaccine doses on days 0 and 3 and should never receive HRIG, as it inhibits the anamnestic antibody response. 1, 2, 4

• Immunocompromised patients (corticosteroid use, HIV, immunosuppressive therapy) require a 5-dose vaccine regimen (days 0,3,7,14,28) plus HRIG 20 IU/kg on day 0, even if previously vaccinated, with mandatory serologic testing 1–2 weeks after the final dose. 1, 4

Efficacy

• When administered promptly and correctly, the combined HRIG and vaccine regimen is nearly 100% effective at preventing human rabies, with no documented failures in the United States since modern biologics were licensed. 1, 4

Tetanus Prophylaxis

• Assess tetanus immunization status and administer tetanus toxoid (Td or Tdap) if the patient has unknown or incomplete immunization, or if more than 5 years have elapsed since the last booster for a contaminated wound. 1, 2

• For patients with no prior tetanus vaccination, administer the first dose of a primary series (0.5 mL Td intramuscularly), with subsequent doses at 4–8 weeks and 6–12 months. 3

Antibiotic Prophylaxis

• Administer amoxicillin-clavulanate 875/125 mg orally twice daily for 3–5 days as first-line prophylactic therapy for Category III dog bites, especially those involving the hand, face, or wounds with penetration of periosteum or joint capsule. 1, 2

• Antibiotic prophylaxis is strongly recommended for patients who are immunocompromised, asplenic, have advanced liver disease, have preexisting edema of the affected area, or have moderate to severe injuries. 1

• For penicillin-allergic patients, use doxycycline 100 mg twice daily, or a fluoroquinolone plus metronidazole, or clindamycin 300 mg three times daily (though clindamycin misses Pasteurella multocida). 1

• Prophylactic antibiotics provide marginal benefit for low-risk wounds (superficial, not on hand/face, immunocompetent host presenting within 12 hours), but the threshold for treatment should be low given the serious consequences of infection. 1

Critical Pitfalls to Avoid

• Never delay wound cleansing—it is the first and most important intervention and should precede all other treatments. 1, 2

• Never initiate unnecessary rabies PEP for healthy domestic dogs that can be observed for 10 days; this wastes resources and exposes patients to unnecessary vaccine risks. 1, 2

• Never suture Category III bite wounds primarily unless absolutely necessary for cosmetic reasons (facial wounds) or to prevent severe functional impairment, as closure dramatically increases infection risk. 1, 2

• Never use the gluteal region for rabies vaccine injection—this is associated with vaccine failure due to inadequate immune response. 1, 2, 4

• Never give HRIG to previously vaccinated immunocompetent persons—this suppresses the memory immune response and is contraindicated. 1, 2, 4

Follow-Up

• If the dog remains healthy for the full 10-day observation period, no rabies prophylaxis is needed and any initiated PEP can be discontinued. 1, 2

• Document the dog's vaccination status, health condition, ability to be observed, and whether the attack was provoked or unprovoked. 1, 2

• Monitor for infectious complications including cellulitis, abscess, septic arthritis, osteomyelitis, and systemic infection—Pasteurella species, staphylococci, streptococci, and Capnocytophaga canimorsus (especially dangerous in asplenic patients) are common pathogens. 1, 2