What is the appropriate management of a mouse bite, including wound cleaning, tetanus prophylaxis, rabies considerations, and antibiotic therapy?

Management of Mouse Bites

Mouse bites should be managed with immediate thorough wound irrigation, tetanus prophylaxis if indicated, and generally do not require rabies prophylaxis or routine antibiotic therapy unless specific high-risk features are present.

Immediate Wound Care

• Irrigate the wound immediately and thoroughly with copious amounts of running tap water or sterile saline until all visible debris is removed. 1
• Running tap water is as effective as sterile saline and superior to antiseptic solutions such as povidone-iodine for wound irrigation. 1, 2
• Continue irrigation until no foreign material is visible in the wound. 1
• Avoid high-pressure irrigation as it can drive bacteria deeper into tissue layers. 3
• After irrigation, cover the wound with a clean occlusive dressing. 1

Debridement

• Remove any necrotic or devitalized tissue if present, as devitalized tissue accelerates bacterial spread and proliferation. 4
• Avoid aggressive debridement that causes additional tissue damage beyond what is necessary to remove nonviable tissue. 1

Wound Closure

• Do not close mouse bite wounds. Most bite wounds should be left open to heal by secondary intention. 1
• Infected wounds or wounds presenting >8 hours after injury should never be closed primarily. 3, 1
• The only exception would be facial wounds requiring cosmetic consideration, which may be closed after meticulous irrigation and prophylactic antibiotics. 3

Tetanus Prophylaxis

• Administer tetanus toxoid (0.5 mL intramuscularly) if the patient's vaccination status is outdated (>10 years for clean wounds, >5 years for contaminated wounds) or unknown. 3, 1
• If the patient has never received Tdap, use the Tdap formulation rather than Td. 1

Rabies Considerations

• Rabies prophylaxis is NOT indicated for mouse bites. Small rodents (including mice, rats, squirrels, hamsters, guinea pigs, gerbils, chipmunks, and rabbits) are almost never found to be infected with rabies and have not been known to transmit rabies to humans. 5
• Rabies immune globulin and vaccine series (days 0,3,7,14, and 28) are reserved for bites from high-risk animals such as bats, raccoons, skunks, foxes, and unvaccinated dogs or cats in endemic areas. 5, 1

Antibiotic Therapy

• Routine prophylactic antibiotics are generally NOT required for most mouse bites unless high-risk features are present. 3, 1

Indications for Prophylactic Antibiotics:

• Hand wounds (highest infection risk location) 3, 1
• Deep puncture wounds 1
• Wounds presenting >8 hours after injury 1
• Wounds with crush injury or devitalized tissue 1
• Immunocompromised patients or those with implanted devices (artificial heart valves, prosthetic joints) 3, 1
• Wounds near joints, bones, feet, face, or genitals 3

First-Line Antibiotic Choice:

• Amoxicillin-clavulanate is the first-line agent for rodent bite prophylaxis and treatment, providing coverage against the polymicrobial flora typically present in mammalian bite wounds. 3, 1
• Prophylactic courses should be given for 3–5 days. 3

Penicillin-Allergic Alternatives:

• Doxycycline monotherapy 3
• Penicillin VK plus dicloxacillin 3
• Fluoroquinolone (ciprofloxacin, levofloxacin, or moxifloxacin) plus metronidazole or clindamycin for anaerobic coverage 3, 1

Antibiotics to Avoid:

• Do NOT use first-generation cephalosporins (cephalexin), penicillinase-resistant penicillins alone (dicloxacillin monotherapy), macrolides (erythromycin), or clindamycin monotherapy, as these have poor coverage against common bite wound pathogens. 1

Wound Care and Follow-Up

• Elevate the injured extremity if swollen to accelerate healing. 3, 1
• Arrange follow-up within 24 hours (by phone or office visit) to assess for signs of infection. 3, 1
• Signs requiring immediate re-evaluation include increasing redness, swelling, foul-smelling drainage, increased pain disproportionate to injury, or fever. 3, 1

Critical Pitfalls to Avoid

• Do not use antiseptic solutions (povidone-iodine) for irrigation—they offer no advantage over water or saline and may impair healing. 1, 2
• Do not close mouse bite wounds (except facial wounds under specific circumstances). 3, 1
• Do not delay initial wound evaluation—early irrigation is the single most important intervention to prevent infection. 3
• Do not administer rabies prophylaxis for mouse bites—small rodents are not rabies vectors. 5
• Do not prescribe antibiotics with inadequate coverage if antibiotics are indicated (avoid cephalexin, macrolides, clindamycin alone). 1