What is the treatment for a mouse bite in the Emergency Department (ED)?

Treatment of Mouse Bites in the Emergency Department

Mouse bites should be thoroughly irrigated with copious amounts of water or saline and treated with prophylactic antibiotics, particularly amoxicillin-clavulanate, due to the risk of infection. 1

Initial Wound Management

• Wound Irrigation: Thoroughly irrigate the wound with a large volume of warm or room temperature potable water for at least 15 minutes to remove any foreign matter 1
• Wound Cleaning: After irrigation, clean the wound with mild soap and water or antiseptic solution
• Debridement: Remove any superficial debris, but avoid deeper debridement unless absolutely necessary 1
• Wound Assessment: Carefully examine the wound for:
  • Depth of penetration
  • Involvement of tendons, joints, or bones
  • Presence of foreign bodies
  • Signs of infection (redness, swelling, warmth)

Antibiotic Prophylaxis

While specific evidence for mouse bites is limited, treatment follows principles established for other mammalian bites:

• First-line antibiotic: Amoxicillin-clavulanate (875/125 mg twice daily for 3-5 days in adults) 2
• For penicillin-allergic patients: Doxycycline (100 mg twice daily) or a combination of clindamycin plus TMP-SMZ 2
• Duration: Typically 3-5 days for prophylaxis; longer if infection develops

Antibiotic prophylaxis is particularly important for:

• Bites to the hand or face
• Deep puncture wounds
• Immunocompromised patients
• Wounds with significant tissue damage

Wound Closure

• Do not close infected wounds 1
• For non-infected wounds:
  • Facial wounds: May be closed primarily after thorough irrigation and cleaning 1
  • Other wounds: Consider leaving open or using Steri-Strips for approximation rather than sutures 1

Tetanus Prophylaxis

• Evaluate tetanus vaccination status
• Administer tetanus toxoid (0.5 mL intramuscularly) if vaccination is outdated (>5 years) or status is unknown 1, 2

Follow-up Care

• Schedule follow-up within 24-48 hours to assess for signs of infection 2
• Instruct patient to monitor for increasing redness, swelling, pain, warmth, or drainage
• Elevate the affected area if there is inflammation to accelerate healing 2
• Consider hospitalization if infection progresses despite appropriate therapy 1

Special Considerations

• Rabies risk: While uncommon in mice, consider rabies prophylaxis if the mouse was wild or appeared sick; consult local health department for guidance 1
• Location-specific concerns: Bites to the hand carry higher infection risk and may require more aggressive treatment 2, 3
• Patient factors: More aggressive treatment may be needed for immunocompromised patients, those with prosthetic joints, or other comorbidities 2

While mouse bites are less commonly reported than dog or cat bites, they should be taken seriously due to potential infection risk. The principles of thorough irrigation, appropriate antibiotic prophylaxis, and careful follow-up are essential to prevent complications.