Rat Bite Treatment
For rat bites, immediately wash the wound thoroughly with soap and water for at least 15 minutes, update tetanus if needed, and give amoxicillin-clavulanate for infected wounds or high-risk locations (hands, near joints/bones), while rabies prophylaxis is NOT required in the United States. 1, 2
Immediate Wound Care (Most Critical Step)
- Wash the wound immediately and thoroughly with soap and water for at least 15 minutes—this single intervention reduces infection risk more effectively than any other measure, including antibiotics. 1
- Follow with copious irrigation using sterile normal saline or water to remove debris and reduce bacterial load. 1, 2
- Avoid using iodine- or antibiotic-containing solutions for routine cleansing, as these are unnecessary and potentially harmful. 2
- Do NOT close infected wounds under any circumstances. 1, 2
- For clean, non-infected wounds seen early (<8 hours), approximate with Steri-Strips rather than sutures to allow drainage. 1, 2
- Exception: Facial wounds may be closed primarily after meticulous irrigation and prophylactic antibiotics. 1, 2
Tetanus Prophylaxis (Mandatory)
- Administer tetanus toxoid 0.5 mL intramuscularly if vaccination status is outdated or unknown. 1, 2
- For dirty wounds, give a booster if >5 years since last dose; for clean wounds, give a booster if >10 years since last dose. 2
Rabies Assessment (Generally NOT Needed)
- Rabies prophylaxis is NOT required for rat bites in the United States—small rodents including rats are not significant rabies vectors. 1, 2
- Consider prophylaxis only in exceptional circumstances involving feral or wild rodent bites in high-prevalence areas after consultation with local health departments. 2
- If indicated, give rabies immune globulin (RIG) at 20 IU/kg infiltrated around the wound plus a 4-dose vaccine series on days 0,3,7, and 14. 1
Antibiotic Management
When to Give Antibiotics:
- Hand wounds or wounds near joints/bones require prophylactic antibiotics due to high infection risk and potential penetration into synovium or bone. 2
- Infected wounds (signs of inflammation, purulence, cellulitis) require treatment antibiotics. 1, 2
- Note: Most uninfected rat bites have a very low natural infection rate (2%) and do not require prophylactic antibiotics if not near high-risk locations. 3, 4
First-Line Oral Therapy:
- Amoxicillin-clavulanate is the first-line oral antibiotic, providing broad coverage for the polymicrobial nature of rat bite infections. 1, 2
Oral Alternatives (Penicillin Allergy):
- Doxycycline 2
- Fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin) PLUS metronidazole or clindamycin 1, 2
- Cephalosporins or penicillinase-resistant penicillins 2
Intravenous Therapy (Severe Infections):
- First-line: Ampicillin-sulbactam or piperacillin-tazobactam 1, 2
- Alternatives: Second-generation cephalosporins (cefoxitin) or carbapenems (ertapenem, imipenem, meropenem) 1, 2
Duration of Treatment:
Special Considerations and Follow-Up
- Elevate injured extremities if swollen to reduce swelling and accelerate healing. 1, 2
- All outpatients require follow-up within 24 hours by phone or office visit. 1, 2
- Hand wounds near joints require expert evaluation for potential penetration into synovium or bone, which may necessitate hospitalization and intravenous antibiotics. 2
- Consider hospitalization if infection progresses despite appropriate antimicrobial therapy, deep tissue involvement is suspected, or the patient is immunocompromised. 1, 2
Common Pitfalls to Avoid
- Do not prioritize antibiotics over wound irrigation—thorough cleansing is more important than antibiotic prophylaxis. 1, 2
- Do not close infected wounds or attempt primary closure of non-facial wounds without careful assessment. 1, 2
- Do not give unnecessary rabies prophylaxis for domestic rat bites in the United States. 1, 2
- Be aware that rat bite fever (Streptobacillus moniliformis) can present without fever and may manifest as polyarthritis, requiring a high index of suspicion. 5, 6, 7