Rabid Dog Scratch on Broken Skin: Category III Exposure
A scratch from a rabid dog that breaks the skin is classified as a Category III exposure, requiring immediate wound washing, human rabies immune globulin (HRIG), and a complete rabies vaccine series. 1
Exposure Classification
The contamination of open wounds, abrasions, or scratches with saliva or other potentially infectious material from a rabid animal constitutes a nonbite exposure that requires full post-exposure prophylaxis. 2 This is distinct from Category II exposures (minor scratches without bleeding) which require vaccine only. 1
Key Defining Features of Category III:
- Any penetration of skin by teeth (bite) 1
- Contamination of mucous membranes with saliva 1
- Contamination of open wounds or scratches with saliva or potentially infectious material 2, 1
Your scenario—a scratch that breaks the skin from a rabid dog—falls squarely into Category III because the scratch created an open wound that was contaminated with potentially infectious material. 2
Required Treatment Protocol
Immediate Wound Management:
- Thorough wound washing for 15 minutes with soap and water is essential and can markedly reduce rabies likelihood 1, 3
- Apply tetanus prophylaxis and antibacterial measures as indicated 4
Post-Exposure Prophylaxis (if previously unvaccinated):
1. Human Rabies Immune Globulin (HRIG):
- Administer 20 IU/kg body weight as soon as possible 1, 4
- Infiltrate as much as anatomically feasible directly into and around the wound 1, 5
- Can be given up to day 7 after first vaccine dose, but should not be delayed 4
2. Rabies Vaccine Series:
- Five doses of HDCV or PCECV (1.0 mL each) given intramuscularly in the deltoid on days 0,3,7,14, and 28 1
- Never administer in the gluteal area 1
If Previously Vaccinated:
Critical Pitfalls to Avoid
Do not delay treatment even if time has passed since exposure—incubation periods exceeding one year have been documented, and prophylaxis should be administered regardless of delay as long as clinical rabies signs are absent. 2
Do not assume the scratch is low-risk because it's not a bite—the contamination of broken skin with saliva from a rabid animal carries significant transmission risk and requires the same aggressive treatment as bite exposures. 2, 4
Do not wait for animal testing results if the dog is confirmed or suspected rabid—initiate prophylaxis immediately. 4 Treatment can be discontinued if subsequent testing proves the animal was not rabid. 4
Why This Matters for Mortality
Rabies is virtually always fatal once clinical disease develops, with only rare survivors documented. 3 However, the rabies vaccine can prevent 99% of deaths if administered promptly after exposure. 6 The combination of HRIG and vaccine provides both immediate passive immunity and long-term active immunity, which is why both components are essential for Category III exposures. 4, 5