Mouse Bite Treatment
For mouse bites, perform thorough wound cleansing with sterile normal saline, ensure tetanus prophylaxis is current (administer Td/Tdap if last dose >10 years ago or status unknown), and consider antibiotic prophylaxis with amoxicillin-clavulanate 500/875 mg twice daily for 3-5 days, particularly for hand bites, immunocompromised patients, or wounds with significant tissue damage.
Wound Management
Immediately cleanse the wound with sterile normal saline—no need for iodine or antibiotic-containing solutions 1. Remove superficial debris carefully. Avoid aggressive debridement that could enlarge the wound and impair healing 1.
Do not close mouse bite wounds primarily except facial wounds managed by a plastic surgeon with meticulous care, copious irrigation, and prophylactic antibiotics 1. For other wounds, approximate margins with Steri-Strips and allow closure by delayed primary or secondary intent 1.
Elevate the injured body part, especially if swollen, during the first few days after injury to accelerate healing 1.
Tetanus Prophylaxis
Administer tetanus toxoid (0.5 mL intramuscularly) if:
For adults, Tdap is preferred over Td if not previously received 3. For children, use age-appropriate DTaP, Td, or Tdap 4.
Tetanus immune globulin (TIG) 250 units IM is indicated if:
- Primary tetanus vaccination series is incomplete or uncertain 4, 2
- Patient is immunocompromised or has advanced liver disease 3
When administering both TIG and tetanus toxoid, use separate syringes at different anatomic sites 4, 5, 6.
Antibiotic Prophylaxis
Amoxicillin-clavulanate 500/875 mg orally twice daily for 3-5 days is the first-line choice 1, 3. This regimen provides coverage against the polymicrobial oral flora typical of rodent bites, including aerobic and anaerobic bacteria.
High-Risk Situations Requiring Prophylaxis:
- Hand bites (NNT = 4 for preventing infection) 7
- Immunocompromised patients 3
- Asplenic patients 3
- Advanced liver disease 3
- Pre-existing or resultant edema of affected area 3
- Moderate to severe injuries 3
- Injuries potentially penetrating periosteum or joint capsule 3
Alternative Antibiotic Regimens:
For penicillin-allergic patients:
- Doxycycline 100 mg twice daily plus metronidazole 250-500 mg four times daily 1
- Fluoroquinolone (ciprofloxacin 500-750 mg twice daily, moxifloxacin 400 mg daily, or levofloxacin 500 mg daily) plus clindamycin 300 mg three times daily 1
For severe infections requiring IV therapy:
- Ampicillin-sulbactam 1.5-3.0 g every 6-8 hours 1
- Piperacillin-tazobactam 3.37 g every 6-8 hours 1
- Carbapenems (ertapenem 1 g daily, imipenem 1 g every 6-8 hours, or meropenem 1 g every 8 hours) 1
Rabies Prophylaxis
Consult local health department immediately to determine if rabies postexposure prophylaxis is indicated 1, 3, 8. Consider rabies risk for:
- Wild or feral rodents
- Geographic areas with high rabies prevalence
- Unusual circumstances suggesting rabid animal behavior
If indicated, administer rabies immunoglobulin on day 0 plus rabies vaccine series at a different anatomic site 1, 8.
Follow-Up
Arrange follow-up within 24 hours by phone or office visit 1. Hospitalize if infection progresses despite appropriate antimicrobial and ancillary therapy 1.
Common Pitfalls
- Avoid first-generation cephalosporins (cephalexin), penicillinase-resistant penicillins (dicloxacillin), macrolides (erythromycin), and clindamycin monotherapy—all have poor activity against Pasteurella multocida, a common pathogen in rodent bites 1
- Do not suture wounds early (<8 hours after injury) except facial wounds by specialists 1
- Hand wounds are more serious than wounds to fleshy body parts and warrant aggressive prophylaxis 1
- Pain disproportionate to injury severity near bone or joint suggests periosteal penetration requiring prolonged therapy (4-6 weeks for osteomyelitis, 3-4 weeks for septic arthritis) 1