What is the recommended treatment for a cat scratch, including wound cleaning, tetanus prophylaxis, and appropriate antibiotic regimen for healthy adults, children, and high‑risk groups such as immunocompromised or pregnant patients?

Cat Scratch Treatment Guide

For cat scratches in healthy adults and children, clean the wound thoroughly with soap and water, administer tetanus prophylaxis according to vaccination history (Tdap preferred if last dose ≥5 years ago for contaminated wounds), and reserve antibiotics for high-risk patients including immunocompromised individuals, those with preexisting edema, or injuries to the hand or face. 1

Immediate Wound Management

All cat scratches require thorough wound cleaning and debridement as the cornerstone of infection prevention. 1

• Irrigate copiously with soap and water to remove saliva and debris that may harbor bacteria 1
• Avoid primary wound closure for most cat scratches; wounds to the face may be approximated after copious irrigation and cautious debridement 1
• Proper wound cleaning is critical for both bacterial infection prevention and tetanus prophylaxis 1

Tetanus Prophylaxis Algorithm

Cat scratches are classified as contaminated, tetanus-prone wounds because they may be contaminated with saliva and create conditions favorable for Clostridium tetani growth. 2

For Patients with ≥3 Previous Tetanus Doses:

• If last dose was <5 years ago: No tetanus vaccination needed 2
• If last dose was ≥5 years ago: Administer tetanus toxoid-containing vaccine WITHOUT tetanus immune globulin (TIG) 1, 2
  • Tdap is strongly preferred over Td if the patient has not previously received Tdap or Tdap history is unknown, as this provides additional pertussis protection 1, 2

For Patients with <3 Doses or Unknown Vaccination History:

• Administer BOTH tetanus toxoid-containing vaccine (Tdap preferred) AND TIG 250 units IM at separate anatomic sites using separate syringes 1, 2
• Treat patients with unknown or uncertain vaccination histories as having zero previous doses 1, 2
• Complete the full 3-dose primary series: second dose ≥4 weeks after first, third dose 6-12 months after second 2

Special Populations:

• Pregnant women: Use Tdap regardless of prior Tdap history if tetanus toxoid is indicated 1, 2
• Immunocompromised patients (HIV, severe immunodeficiency): Administer TIG regardless of tetanus immunization history when contaminated wounds are present 1, 2
• Patients with history of Arthus reaction: Do not administer tetanus toxoid until >10 years after most recent dose, even with contaminated wounds; TIG decision still based on primary vaccination history 1, 2

Antibiotic Prophylaxis

Preemptive antibiotic therapy for 3-5 days is recommended for high-risk patients only. 1

High-Risk Criteria Requiring Antibiotics:

• Immunocompromised patients 1
• Asplenic patients 1
• Advanced liver disease 1
• Preexisting or resultant edema of the affected area 1
• Moderate to severe injuries, especially to the hand or face 1
• Injuries that may have penetrated the periosteum or joint capsule 1

Antibiotic Selection:

Amoxicillin-clavulanate is the first-line agent, providing coverage against both aerobic and anaerobic bacteria commonly found in cat scratches. 1

• Adult dosing: Amoxicillin-clavulanate per standard dosing guidelines 1
• This agent covers Pasteurella multocida, the most common pathogen in cat bites and scratches, as well as anaerobes 1

Rabies Considerations

Consult local health officials to determine if rabies postexposure prophylaxis should be initiated. 1

• The decision depends on local rabies epidemiology and whether the cat is available for 10-day observation 1
• In the United States, domestic cats available for observation typically do not require immediate rabies prophylaxis 3

Critical Clinical Pearls and Common Pitfalls

Do not confuse the 10-year routine booster interval with the 5-year interval for contaminated wounds—this is the most common error in tetanus prophylaxis. 2

• Cat scratches are contaminated wounds requiring the 5-year interval, not the 10-year interval used for clean, minor wounds 2
• More frequent tetanus vaccination than recommended increases the risk of Arthus-type hypersensitivity reactions 1, 2
• Tetanus can occur even in previously immunized patients who do not receive appropriate prophylaxis after high-risk exposure 4, 3
• A case report documented generalized tetanus after cat scratches in a previously immunized patient whose last booster was 5 years prior, highlighting the importance of adhering to the 5-year interval for contaminated wounds 3

Follow-Up Considerations

• Monitor for signs of infection: increasing redness, swelling, purulent drainage, fever 1
• Ensure completion of tetanus primary series if initiated 2
• For patients receiving TIG, emphasize that passive immunization does not provide long-term immunity and the full vaccination series must be completed 2