Antibiotic Recommendation for Scratches at Risk of Infection
Direct Recommendation
For scratches at risk of infection, amoxicillin-clavulanate 875/125 mg twice daily for 3-5 days is the recommended first-line antibiotic therapy. 1
When to Prescribe Antibiotics for Scratches
Preemptive antibiotic therapy is indicated for scratches in patients who meet any of the following high-risk criteria: 1
- Immunocompromised status (including diabetes, HIV, chronic steroid use) 1
- Asplenia 1
- Advanced liver disease 1
- Pre-existing or resultant edema of the affected area 1
- Moderate to severe injuries, especially involving the hand or face 1
- Injuries that may have penetrated the periosteum or joint capsule 1
Why Amoxicillin-Clavulanate is First-Line
Amoxicillin-clavulanate provides comprehensive coverage against both aerobic and anaerobic bacteria that commonly contaminate traumatic wounds, including Staphylococcus aureus, streptococci, and gram-negative organisms. 1, 2 The clavulanic acid component protects against beta-lactamase producing organisms, which is critical for polymicrobial wound infections. 2
This antibiotic achieves excellent tissue penetration with therapeutic levels found in interstitial fluid, making it ideal for skin and soft tissue infections. 3
Alternative Options for Penicillin Allergy
If the patient has a penicillin allergy: 1
- Doxycycline 100 mg twice daily - provides good coverage but some streptococci may be resistant 1
- Moxifloxacin 400 mg daily - offers monotherapy with good anaerobic coverage 1
- Combination therapy: Ciprofloxacin 500-750 mg twice daily PLUS metronidazole 250-500 mg three times daily for comprehensive aerobic and anaerobic coverage 1
Critical Pitfalls to Avoid
Do NOT use first-generation cephalosporins (cephalexin) as monotherapy for contaminated wounds or scratches at risk of infection - they miss anaerobic bacteria that are commonly present in traumatic wounds. 1 While cephalexin is effective for simple staphylococcal and streptococcal skin infections 4, it lacks the broad-spectrum coverage needed for potentially contaminated scratches.
Avoid clindamycin monotherapy - it misses Pasteurella multocida and some gram-negative organisms that may contaminate scratches. 1
Treatment Duration and Timing
- Duration: 3-5 days for preemptive therapy in high-risk wounds 1
- Timing: Start antibiotics as soon as possible, as delay beyond 3 hours increases infection risk 2
- Tetanus prophylaxis: Administer tetanus toxoid if vaccination is not current within 10 years 2
Additional Wound Management
Before antibiotic administration, thorough irrigation and debridement of devitalized tissue is essential. 2 Antibiotics are an adjunct to, not a replacement for, proper wound care.
When to Escalate Therapy
If signs of infection develop despite oral therapy (increasing pain, redness, swelling, purulent drainage), consider: 2