Which patients with lacerations or abrasions should be prescribed antibiotics to prevent infection?

Antibiotic Prophylaxis for Lacerations and Abrasions

Prophylactic antibiotics are NOT necessary for simple, clean lacerations and abrasions, but ARE indicated for high-risk wounds including those with significant contamination, tissue damage, immunocompromised patients, bites, or injuries involving deeper structures. 1

Simple, Clean Wounds: No Antibiotics Needed

• Simple, clean finger and hand lacerations without contamination do not require prophylactic antibiotics, as infection rates are extremely low (approximately 1%). 1
• Multiple randomized trials of uncomplicated hand lacerations show no statistical benefit from antibiotic prophylaxis, with relative risks of infection ranging from 0.73 to 1.07 (all confidence intervals crossing 1.0). 2
• This principle extends to other simple lacerations on the body without high-risk features. 3

High-Risk Wounds Requiring Antibiotics

Prescribe prophylactic antibiotics for 3-5 days when ANY of the following high-risk features are present: 1

Patient Factors

• Immunocompromised status (diabetes, HIV, chronic steroids, chemotherapy) 1
• Preexisting or resultant edema at the wound site 1

Wound Characteristics

• Significant contamination with soil, debris, or feces 1, 4
• Moderate to severe tissue damage or ischemic tissue 5, 1
• Injuries penetrating periosteum or joint capsule 1
• Human or animal bites to the hand or any body part 1
• Wounds from animal gutting or similar high-contamination activities 4

Location-Specific Considerations

• Oral lacerations may warrant antibiotics for complex injuries, though evidence is mixed 6
• Finger and hand wounds meeting high-risk criteria above 1

Recommended Antibiotic Regimens

For High-Risk Prophylaxis (3-5 days):

• First-line: Amoxicillin-clavulanate 875/125 mg twice daily orally, providing coverage against aerobic and anaerobic bacteria 1
• Duration: 3-5 days for high-risk wounds 1
• Start as soon as possible after injury 1

For Contaminated/Therapeutic Treatment:

• First-generation cephalosporin (cefazolin) as baseline coverage for Staphylococcus aureus and streptococci 5, 1, 4
• Add aminoglycoside (gentamicin) for severe injuries with gram-negative risk 5, 1, 4
• Add penicillin for soil contamination or ischemic tissue to cover Clostridium species 5, 1, 4
• Duration: 48-72 hours for contaminated wounds; up to 3-5 days for severe contamination 1, 4

Critical Timing Considerations

• Antibiotics should be started as soon as possible when indicated—delaying beyond 3 hours significantly increases infection risk in contaminated wounds. 1, 4
• For surgical wound closure, antibiotics must be given within 60 minutes before incision. 1

Common Pitfalls to Avoid

• Do not prescribe antibiotics for simple, clean lacerations—this contributes to antibiotic resistance without clinical benefit. 1, 2
• Do not use prophylactic doses for contaminated wounds—these require therapeutic dosing. 7, 4
• Do not forget anaerobic coverage (penicillin) for soil-contaminated wounds or animal-related injuries. 5, 4
• Do not extend therapy beyond 5 days for most wounds—longer courses increase resistance risk without added benefit. 1, 8
• Research shows 2-day regimens are as effective as 5-day regimens for contaminated wounds, so avoid unnecessarily prolonged courses. 8