Rat Bite Management
Rabies post-exposure prophylaxis is generally NOT indicated for rat bites, but consultation with local health officials is recommended to determine if vaccination should be initiated based on local epidemiology 1.
Rabies Risk Assessment
Rats and other small rodents (including mice, squirrels, hamsters, guinea pigs, gerbils, chipmunks, rabbits, and hares) are almost never found to be infected with rabies and have not been known to transmit rabies to humans in the United States. The decision to initiate rabies PEP should be made in consultation with local or state health departments, as they can provide guidance based on local animal rabies surveillance data 1.
If Rabies PEP Is Deemed Necessary
Should local health officials determine rabies prophylaxis is warranted (which would be exceptional for rat bites), the protocol for previously unvaccinated persons includes 2:
- Immediate thorough wound cleansing with soap and water, ideally using a virucidal agent like povidone-iodine solution
- Human Rabies Immune Globulin (HRIG): 20 IU/kg body weight, infiltrated around and into the wound if anatomically feasible, with remaining volume given IM at a site distant from vaccine administration
- Rabies vaccine (HDCV or PCECV): 1.0 mL IM in deltoid (or outer thigh in young children) on days 0,3,7, and 14
- Note: Immunocompromised patients require a 5-dose schedule (add day 28)
Comprehensive Wound Management
Wound Care
All rat bite wounds require immediate thorough cleansing with soap and water 2, 3. This is the single most important intervention to prevent infection.
Tetanus Prophylaxis
Tetanus prophylaxis is mandatory for rat bites, as most patients presenting with these injuries are deficient in tetanus immunization 3. Follow standard tetanus prophylaxis guidelines based on vaccination history and wound characteristics.
Antibiotic Management
Prophylactic antibiotics are NOT routinely recommended for rat bites due to the low natural infection rate (only 2% in prospective studies) 3. However, preemptive antimicrobial therapy for 3-5 days should be considered for patients with 1:
- Immunocompromised status
- Asplenia
- Advanced liver disease
- Preexisting or resultant edema of the affected area
- Moderate to severe injuries, especially to the hand or face
- Injuries that may have penetrated the periosteum or joint capsule
When antibiotics are indicated, use amoxicillin-clavulanate 875/125 mg twice daily as first-line therapy, which covers both aerobic and anaerobic bacteria commonly found in bite wounds 1.
Treatment of Established Infections
If infection develops despite initial management, use a cephalosporin or penicillinase-resistant penicillin with appropriate surgical wound care 3. Most rat bite wounds are superficial (Type I scratches) and require only conservative wound care management 4. Deeper wounds with infection (Type II) may require drainage and debridement, while full-thickness injuries with tissue loss (Type III) may require skin grafting 4.
Clinical Pitfalls
- Most rat bites occur during sleep (72% of cases), predominantly affecting exposed areas of upper extremities and face 3
- Avoid routine prophylactic antibiotics unless high-risk features are present—overuse contributes to resistance without clear benefit
- Do not assume rabies risk is significant—rats are extremely low-risk vectors, unlike dogs, bats, raccoons, and foxes
- Ensure tetanus status is current—this is often overlooked but critically important