What antibiotics are appropriate for a healthy adult with a small (<2% total body surface area) superficial burn, including first‑line agents and options for MRSA or β‑lactam allergy?

Antibiotic Management for Small Superficial Burns in Healthy Adults

Primary Recommendation

Prophylactic systemic antibiotics are not indicated for small (<2% TBSA) superficial burns in healthy adults and should be avoided to prevent bacterial resistance. 1, 2

When Antibiotics Are NOT Needed

• For uncomplicated superficial burns without clinical signs of infection, no antibiotics should be prescribed. 1, 2
• Prophylactic antibiotic use in outpatient burn management may increase bacterial resistance without providing benefit 1
• Systemic antibiotic prophylaxis in non-surgical burn patients showed no evidence of reducing burn wound infection rates 2

When to Consider Antibiotics

Systemic antibiotics should only be administered if clinical signs of infection develop, including: 3

• Purulent drainage from the wound
• Expanding erythema beyond the burn margin
• Increased warmth, swelling, or tenderness
• Fever or systemic signs of infection
• Sloughy or crusted areas with positive bacterial cultures

First-Line Antibiotic Selection (If Infection Develops)

For Presumed Methicillin-Susceptible S. aureus (MSSA):

• Cephalexin 500 mg orally four times daily for 7 days 4, 5
• Alternative: Dicloxacillin 250 mg orally four times daily for 7 days 5

For Suspected or Confirmed MRSA:

• Clindamycin 300-450 mg orally FOUR times daily (not three times daily) for 7 days 4, 5
• Alternative: Trimethoprim-sulfamethoxazole (TMP-SMX) 1-2 double-strength tablets (160/800 mg) twice daily for 7 days 4, 5
• Note: TMP-SMX lacks reliable coverage against beta-hemolytic streptococci 4

β-Lactam Allergy Options

For Penicillin-Allergic Patients:

• Clindamycin 300-450 mg orally four times daily for 7-10 days is the preferred agent, providing coverage against both streptococci and methicillin-sensitive S. aureus 4, 5
• First-generation cephalosporins (cephalexin) can be used except in patients with immediate hypersensitivity reactions 5, 6
• There is little clinically significant immunologic cross-reactivity between penicillins and other beta-lactams 6

Topical Antimicrobial Management

For superficial burns, topical antimicrobials should be applied to sloughy areas only, not prophylactically to all burn surfaces: 3

• Apply topical antimicrobial agents guided by local microbiological advice 3
• Consider silver-containing products/dressings for sloughy areas 3
• Avoid silver sulfadiazine as primary prophylaxis, as it is associated with increased burn wound infection rates (OR 1.87) and longer hospital stays compared to dressings 2

Wound Care Without Antibiotics

The cornerstone of small superficial burn management is proper wound care, not antibiotics: 3, 1

• Regularly cleanse wounds with warmed sterile water, saline, or chlorhexidine (1/5000) 3
• Apply greasy emollient (50% white soft paraffin with 50% liquid paraffin) over the entire burn surface 3
• Use nonadherent dressings to protect the wound and promote a moist healing environment 3, 1

Critical Pitfalls to Avoid

• Do not prescribe prophylactic antibiotics for uncomplicated superficial burns – this increases resistance without benefit 1, 2
• Do not use silver sulfadiazine routinely – evidence shows it increases infection rates 2
• Do not underdose clindamycin – the correct dose is 300-450 mg FOUR times daily, not three times daily 4
• Do not assume cephalexin will work for MRSA – it has no activity against MRSA and should not be used when MRSA is suspected 7
• Do not continue ineffective antibiotics – if no improvement occurs within 48-72 hours, suspect MRSA and switch therapy 7

Special Populations Requiring Lower Threshold for Treatment

Patients with diabetes mellitus are at increased risk of complications and infection; consider early referral to a burn center and lower threshold for antibiotic initiation. 1