What is the treatment for an animal bite?

Animal Bite Treatment

For animal bites, immediately irrigate the wound copiously with sterile normal saline, administer amoxicillin-clavulanate prophylaxis for high-risk wounds (hand injuries, puncture wounds, immunocompromised patients, or wounds near joints/bones), update tetanus if needed, and confine healthy dogs/cats/ferrets for 10-day observation without initiating rabies prophylaxis unless the animal develops signs of illness. 1

Immediate Wound Management

• Irrigate the wound thoroughly with sterile normal saline using a 20-mL or larger syringe for at least 15 minutes—this is the single most effective measure for preventing infection and rabies transmission. 1, 2
• Explore the wound for tendon or bone involvement, joint capsule penetration, and foreign bodies, as these findings mandate more aggressive treatment. 1, 2
• Remove only superficial debris with cautious debridement; avoid enlarging the wound unnecessarily. 3
• Do not close most bite wounds except facial wounds, which should receive primary closure after copious irrigation and debridement for optimal cosmetic results. 1
• Non-facial wounds may be approximated with Steri-Strips rather than sutured, or left to heal by secondary intention. 1, 3

Antibiotic Prophylaxis

Amoxicillin-clavulanate 875/125 mg twice daily is the first-line antibiotic for both prophylaxis and treatment, providing coverage against Pasteurella multocida and anaerobes commonly found in animal bite wounds. 1, 2

Indications for Prophylactic Antibiotics (3-5 days):

• Immunocompromised, asplenic, or advanced liver disease patients 1
• Hand wounds or wounds near joints/bones (high risk of penetration into periosteum or joint capsule) 1, 3
• Puncture wounds, especially cat bites which have twofold higher infection risk 2, 4
• Moderate to severe injuries or wounds with edema 1

Alternative Antibiotic Options:

• Oral alternatives: Doxycycline (excellent Pasteurella coverage) or fluoroquinolones with anaerobic coverage 1
• IV options for severe infections: Ampicillin-sulbactam, piperacillin-tazobactam, second-generation cephalosporins, or carbapenems 1, 3
• Treatment duration: 7-10 days for standard infections, 4 weeks for septic arthritis, 6 weeks for osteomyelitis 1

Tetanus Prophylaxis

• Administer tetanus toxoid 0.5 mL intramuscularly if vaccination status is outdated or unknown. 3
• For dirty wounds: Booster needed if >5 years since last dose 3
• For clean wounds: Booster needed if >10 years since last dose 3
• Prefer Tdap over Td if patient has not previously received pertussis vaccination. 1

Rabies Risk Assessment and Management

For Dog, Cat, or Ferret Bites:

A healthy dog, cat, or ferret that bites should be confined and observed daily for 10 days without administering rabies vaccine during the observation period. 5, 1

• A healthy domestic animal that remains alive and healthy for 10 days would not have been shedding rabies virus at the time of the bite. 1
• Do not initiate rabies prophylaxis immediately if the animal is available for observation. 1
• If the animal develops signs of rabies during observation (behavioral changes, paralysis, excessive salivation, aggression, neurological signs), euthanize immediately and submit the head for laboratory testing while simultaneously initiating post-exposure prophylaxis (PEP). 5, 1
• Any stray or unwanted animal may be euthanized immediately and the head submitted for rabies examination, with PEP initiated without waiting for results. 5, 1

Rabies Post-Exposure Prophylaxis (If Indicated):

For previously unvaccinated individuals:

• Administer human rabies immune globulin (HRIG) 20 IU/kg on day 0, infiltrating the full dose around and into the wound if anatomically feasible, with remaining volume injected intramuscularly at a site distant from vaccine administration. 1, 2
• Administer rabies vaccine on days 0,3,7, and 14. 1, 2
• Never administer HRIG in the same syringe or at the same anatomical site as the vaccine. 1

For previously vaccinated individuals:

• Administer only 2 doses of vaccine on days 0 and 3—do NOT give HRIG as it will suppress the anamnestic antibody response. 1

Special Rabies Considerations:

• Wild carnivorous mammals and bats that bite should be euthanized and tested; initiate PEP immediately without waiting for results. 5
• Small rodents (rats, mice) rarely carry rabies in the United States; prophylaxis is generally not required, but consult local health departments for regional risk assessment. 3
• Rabies PEP should be administered regardless of delay, as incubation periods exceeding 1 year have been documented. 1
• Consult local health officials to determine regional rabies epidemiology and need for prophylaxis. 1, 2

Follow-Up Care

• All patients must be seen within 48-72 hours to assess for signs of infection (cellulitis, lymphangitis, abscess formation) and evaluate wound healing. 1, 4
• Hand wounds require special attention due to higher risk of infection and functional complications; consider expert evaluation for potential deep tissue involvement. 1, 3
• Elevate the injured extremity to reduce swelling and accelerate healing. 3

Critical Pitfalls to Avoid

• Do not withhold PEP if the animal is unavailable for observation or shows any signs of illness during the observation period. 1
• Do not close infected wounds; use delayed primary or secondary closure instead. 3
• Do not use iodine- or antibiotic-containing solutions for routine wound cleansing. 3
• Immunocompromised patients require more aggressive follow-up and lower threshold for hospitalization due to higher infection risk. 1
• Any penetration of skin by teeth constitutes a bite exposure requiring evaluation, regardless of wound severity. 1