How should I manage a 28-year-old male with a cat scratch on the ventral ankle who has never received rabies or tetanus vaccination?

Management of Cat Scratch in an Unvaccinated 28-Year-Old Male

This patient requires immediate wound care, tetanus prophylaxis, and rabies risk assessment—but likely does NOT need rabies post-exposure prophylaxis if the cat can be observed for 10 days and remains healthy.

Immediate Wound Management

• Thoroughly wash and flush the scratch with soap and water for approximately 15 minutes immediately, as this is the single most effective measure for preventing both rabies and bacterial infection 1, 2, 3.
• Apply povidone-iodine solution or similar virucidal agent to the wound after soap-and-water cleansing to further reduce viral and bacterial load 1, 2, 3.
• Examine the wound carefully for depth, potential tendon involvement, joint capsule penetration, or bone involvement—though a 1 cm superficial scratch on the ankle is unlikely to have these complications 4, 5.
• Do not suture the wound unless absolutely necessary for cosmetic reasons (not applicable here); primary closure increases infection risk 5, 3.

Tetanus Prophylaxis (Critical Priority)

This patient MUST receive tetanus vaccination immediately since he has never been vaccinated 1, 6.

• Administer Td (Tetanus-Diphtheria) 0.5 mL intramuscularly in the deltoid as the first dose of a primary immunization series 1, 6.
• Schedule two additional doses: the second dose 4-8 weeks after the first, and the third dose 6-12 months after the second to complete primary immunization 6.
• For wound management in previously unvaccinated patients with any wound other than clean/minor wounds, both Td vaccine AND Tetanus Immune Globulin (TIG) are indicated 6. However, a simple cat scratch may be considered a clean minor wound, in which case Td alone suffices 6.

Common pitfall: Do not delay tetanus prophylaxis—it should be administered as soon as possible during the initial visit 1, 7.

Rabies Risk Assessment and Post-Exposure Prophylaxis Decision

Step 1: Determine if the cat can be observed

• If the cat is a healthy domestic pet that can be confined and observed for 10 days, do NOT initiate rabies post-exposure prophylaxis immediately 1, 3, 8.
• Begin prophylaxis only if the cat develops clinical signs of rabies during the 10-day observation period 1, 3, 8.
• If the cat remains healthy for the full 10 days, no rabies prophylaxis is needed, as the cat was not shedding rabies virus at the time of the scratch 1, 2, 3, 8.

Step 2: When to initiate immediate rabies prophylaxis

Initiate rabies post-exposure prophylaxis immediately if any of the following apply 1, 3, 8:

• The cat is stray, unwanted, or cannot be confined for observation
• The cat escapes or is unavailable for observation
• The cat dies or develops illness suggestive of rabies before completing the 10-day observation
• The cat shows signs of rabies during observation
• The cat's vaccination status is unknown or inadequate AND observation is not possible
• Local epidemiology suggests high rabies risk in cats

Step 3: Rabies post-exposure prophylaxis regimen (if indicated)

For a previously unvaccinated person, administer BOTH rabies immune globulin (RIG) and rabies vaccine 1, 2, 3, 8:

• Human Rabies Immune Globulin (HRIG) 20 IU/kg body weight on day 0: infiltrate up to half the dose into and around the wound if anatomically feasible; inject the remainder intramuscularly in the gluteal region 2, 3.
• Rabies vaccine (HDCV, RVA, or PCEC) intramuscularly in the deltoid (never in the gluteal area, as this results in lower antibody titers) on days 0,3,7, and 14 (4-dose regimen for immunocompetent patients) 2, 8.
• HRIG can be administered up to day 7 after the first vaccine dose if not given initially; beyond day 7, HRIG is not indicated as vaccine-induced antibodies are presumed present 2, 5.

Critical pitfall: Never administer more than 20 IU/kg of HRIG, as excess may suppress active antibody production 2.

Antibiotic Considerations

For this simple, superficial 1 cm scratch with no signs of infection, prophylactic antibiotics are NOT routinely indicated 1, 4.

However, consider amoxicillin-clavulanate 875/125 mg twice daily for 3-5 days if 1, 4:

• The scratch is deep or shows early signs of infection (increasing redness, warmth, swelling, purulent drainage)
• The patient is immunocompromised
• The wound involves the hand, face, or area over joints/tendons
• There is significant edema of the affected area

Alternative for penicillin-allergic patients: doxycycline 100 mg twice daily or a fluoroquinolone plus clindamycin 1.

Monitoring for Cat Scratch Disease

Educate the patient to watch for signs of cat scratch disease over the next 3-30 days 1:

• Development of a papule or pustule at the scratch site
• Regional lymphadenopathy (typically 3 weeks post-exposure)
• Fever or systemic symptoms

If lymphadenopathy develops, treat with azithromycin 500 mg on day 1, then 250 mg daily for 4 additional days (patient weighs >45 kg) 1.

Follow-up Plan

• Recheck the wound in 24-48 hours for signs of infection 4.
• Confirm the cat's health status at day 10 if observation is being conducted 1, 3, 8.
• Schedule return visits for completion of tetanus primary series at 4-8 weeks and 6-12 months 6.
• Instruct the patient to return immediately if fever, increasing pain, redness, swelling, purulent drainage, red streaking, or lymph node enlargement develops 4.

Documentation Requirements

• Document the cat's vaccination status, health status, and availability for observation 1, 3, 8.
• Document whether the scratch was provoked or unprovoked (unprovoked attacks are more likely to indicate rabies) 1, 2, 8.
• Document consultation with local public health officials if rabies risk is uncertain 1, 3, 8.