How should I manage a cat scratch wound in a healthy adult, including wound cleaning, tetanus prophylaxis, indications for prophylactic antibiotics, and follow‑up?

Management of Cat Scratch Wounds in Healthy Adults

Clean the wound thoroughly with sterile normal saline, update tetanus if needed, and prescribe amoxicillin-clavulanate 875/125 mg twice daily for 3-5 days for deep wounds, hand/face/joint injuries, or any scratch presenting after 8-12 hours. 1, 2

Immediate Wound Care

Wound cleaning is the cornerstone of initial management:

• Irrigate thoroughly with sterile normal saline to remove superficial debris—no need for iodine or antibiotic-containing solutions 1
• Avoid deep debridement unless significant devitalized tissue is present, as this can enlarge the wound and impair healing 1, 2
• Do not close infected wounds; for fresh wounds, primary closure within 8 hours is controversial—consider Steri-Strips with delayed closure instead 1
• Facial wounds are an exception and may be closed primarily by a plastic surgeon after meticulous irrigation and prophylactic antibiotics 1

Tetanus Prophylaxis

Update tetanus immunization if the last dose was >5 years ago for contaminated wounds or >10 years for clean wounds:

• Administer 0.5 mL tetanus toxoid intramuscularly if status is outdated or unknown 1
• This is critical—failure to provide appropriate tetanus prophylaxis after high-risk injuries can lead to severe disease even in previously vaccinated individuals 3

Indications for Prophylactic Antibiotics

Prophylactic antibiotics are strongly recommended for:

• Deep puncture wounds (cat scratches can penetrate deeper than they appear) 2, 4
• Wounds on hands, feet, face, or near joints—hand wounds carry the highest infection risk 1, 2, 4, 5
• Any wound presenting >8-12 hours after injury with early signs of infection 2, 4
• Immunocompromised patients (even minor scratches warrant treatment) 2, 4

The infection risk for cat scratches is approximately 10-20%, significantly lower than cat bites (30-50%), but still substantial enough to warrant prophylaxis in high-risk scenarios. 2

First-Line Antibiotic Therapy

Amoxicillin-clavulanate 875/125 mg orally twice daily for 3-5 days is the definitive first-line choice:

• Provides optimal coverage against Pasteurella multocida (present in 75% of cat wounds), staphylococci, streptococci, and anaerobes 1, 2, 4, 5
• This combination has been studied specifically for animal bite/scratch wounds and is guideline-recommended 1

Alternative Regimens for Penicillin Allergy

For patients with penicillin allergy:

• Doxycycline 100 mg twice daily is the preferred alternative with excellent P. multocida activity 1, 2, 4
• Fluoroquinolones (ciprofloxacin 500-750 mg twice daily or levofloxacin 750 mg daily) provide good coverage but may require additional anaerobic coverage with metronidazole or clindamycin 1, 2, 4
• TMP-SMZ plus metronidazole is another option for combined aerobic/anaerobic coverage 1, 2, 4

Antibiotics to AVOID

Critical pitfall: Several commonly prescribed antibiotics have poor activity against P. multocida and should NOT be used:

• First-generation cephalosporins (cephalexin) 1, 2, 4
• Penicillinase-resistant penicillins (dicloxacillin) 1, 4
• Macrolides (erythromycin) 1, 4
• Clindamycin as monotherapy 1, 2, 4

These agents are frequently prescribed for skin infections but will fail in cat scratch/bite scenarios due to inadequate Pasteurella coverage.

Adjunctive Measures

Beyond antibiotics, several supportive measures accelerate healing:

• Elevate the injured body part, especially if swollen, using a sling for outpatients 1, 2
• This passive elevation significantly accelerates healing during the first few days after injury 1

Follow-Up and Red Flags

Arrange follow-up within 24 hours by phone or office visit:

• Instruct patients to return immediately for increasing pain, redness, swelling, purulent drainage, fever, or decreased range of motion 2, 4
• Pain disproportionate to injury severity near a bone or joint suggests periosteal penetration—this requires urgent evaluation for septic arthritis or osteomyelitis 1
• Hand wounds are particularly serious and warrant closer monitoring than wounds to fleshy body parts 1

When to Escalate Care

Consider hospitalization and IV antibiotics if:

• Infection progresses despite appropriate oral therapy 1
• Deep tissue involvement, systemic signs, or complications develop 2, 4
• IV options include ampicillin-sulbactam 1.5-3.0 g every 6-8 hours or carbapenems for penicillin-allergic patients 1, 4

Special Consideration: Cat Scratch Disease

If lymphadenopathy develops 1-3 weeks after the scratch, consider Bartonella henselae (cat scratch disease):

• Most cases are self-limited and resolve without antibiotics in 2-4 months 6, 7, 8
• If treatment is indicated (severe symptoms, immunocompromised host), azithromycin 500 mg day 1, then 250 mg daily for 4 days is the regimen of choice 2, 7
• Immunocompromised patients risk atypical presentations including bacillary angiomatosis and require more aggressive management 9, 2

Rabies Risk Assessment

Rabies prophylaxis is generally not needed for domestic indoor cats but should be considered for:

• Scratches from unknown, feral, or wild cats 1, 2
• Consult local health department about regional rabies prevalence and need for post-exposure prophylaxis 1