What treatment should be given to a patient bitten by a cat with an unknown rabies status, who has swelling despite antibiotics, a clean wound, and whose last Tetanus Toxoid (TT) vaccination was more than 10 years ago?

Treatment for Cat Bite with Swelling and Outdated Tetanus Vaccination

Give TT (Tdap preferred) and observe the cat for 10 days—no rabies prophylaxis is needed for a domestic cat bite when the animal is available for observation. 1

Tetanus Prophylaxis

This patient requires tetanus toxoid immediately because the last dose was >10 years ago and cat bites are classified as contaminated, tetanus-prone wounds. 2, 3

• Cat bites are contaminated wounds (puncture wounds with potential for dirt, saliva, and anaerobic conditions), which triggers the 5-year interval rule rather than the 10-year rule for tetanus boosters. 2, 3

• Since the last TT was >10 years ago, tetanus toxoid-containing vaccine is indicated without TIG because the patient has completed the primary vaccination series (≥3 doses). 2, 3

• Tdap is strongly preferred over Td if the patient has not previously received Tdap or Tdap history is unknown, as this provides additional protection against pertussis. 1, 2

• TIG is not required for patients with documented complete primary vaccination series (≥3 lifetime doses), even with contaminated wounds. 2, 3

Rabies Management

Rabies vaccine and immunoglobulin are NOT indicated for domestic cat bites when the cat is available for observation. 1

• The standard approach for domestic cat bites in most settings is to observe the cat for 10 days for signs of rabies. 1, 2

• Rabies post-exposure prophylaxis (vaccine + immunoglobulin) is only initiated if:

  • The cat is unavailable for observation (escaped, killed, unknown ownership) 1
  • The cat develops signs of rabies during the 10-day observation period 1
  • The cat tests positive for rabies 1
  • Local health officials determine the cat is high-risk based on epidemiologic factors 1

• If rabies prophylaxis becomes necessary, previously unvaccinated persons require both HRIG (20 IU/kg infiltrated around wound) and rabies vaccine series (5 doses over 28 days). 1

Antibiotic Management

The swelling despite antibiotics suggests inadequate wound management or resistant organisms—reassess antibiotic choice and wound care. 1

• Amoxicillin-clavulanate is the recommended first-line antibiotic for cat bites, as it covers both aerobic and anaerobic bacteria including Pasteurella multocida, the most common pathogen in cat bites. 1

• If swelling persists despite appropriate antibiotics, consider:

  • Inadequate wound irrigation and debridement 1
  • Resistant organisms requiring culture-guided therapy 1
  • Deep space infection or abscess requiring surgical drainage 1

Critical Clinical Algorithm

1. Immediate wound management: Copious irrigation with water or dilute povidone-iodine solution, cautious debridement 1

2. Tetanus prophylaxis: Administer Tdap (or Td if Tdap previously received) immediately 2, 3

3. Rabies assessment: Identify cat ownership and availability for 10-day observation 1

   • If cat available → observe for 10 days, no rabies prophylaxis 1
   • If cat unavailable → consult local health officials, likely initiate rabies PEP 1

4. Antibiotic optimization: Ensure amoxicillin-clavulanate coverage, reassess wound 1

Common Pitfalls to Avoid

• Do not give TIG to patients with documented complete primary tetanus vaccination series—this is unnecessary and wasteful. 2, 3

• Do not initiate rabies prophylaxis for domestic cat bites when the cat is available for observation—this is the most common error in rabies management. 1

• Do not confuse the 10-year routine booster interval with the 5-year interval for contaminated wounds—cat bites require the 5-year rule. 2, 3

• Do not delay tetanus prophylaxis—although there is no urgent rush in the immediate hours after injury, it should be administered within 24-48 hours as part of standard wound management. 4