Antibiotic Therapy for Burns in Patients with Cephalexin Allergy

First-line Antibiotic Options

The Infectious Diseases Society of America recommends clindamycin as the first-line antibiotic therapy for patients with burns who are allergic to cephalexin, due to its excellent coverage against common burn pathogens and safety in patients with cephalosporin allergies 1, 2
Clindamycin provides excellent coverage against Staphylococcus aureus (including MSSA) and Streptococcus species, with a recommended dosage of 300-450 mg orally four times daily for adults or 20 mg/kg/day in 3 divided doses for children 1, 2, 3

For mild to moderate burns, trimethoprim-sulfamethoxazole is a suitable alternative, with bactericidal activity against many common skin pathogens and no cross-reactivity with cephalosporins, at a dosage of 1-2 double-strength tablets twice daily for adults 1, 2, 3, 4, 5
For moderate to severe burns, linezolid is an effective option, with no cross-reactivity with beta-lactams and effectiveness against MRSA and other resistant gram-positive organisms, at a dosage of 600 mg orally twice daily for adults 1, 2, 3, 6
For severe burns requiring IV therapy, vancomycin is the parenteral drug of choice, with effectiveness against MRSA and a recommended dosage of 30 mg/kg/day in 2 divided doses IV for adults 1, 2

The nature of the cephalexin allergy is important to determine, with immediate-type (IgE-mediated) reactions requiring avoidance of other cephalosporins with similar side chains 4, 6
Cross-reactivity between cephalosporins is primarily based on R1 side chains, not the beta-lactam ring itself, and cephalexin shares identical R1 side chains with amoxicillin 6
For patients with severe immediate-type reactions to cephalexin, all beta-lactam antibiotics including penicillins should be avoided, and clindamycin is the safest alternative 1, 2, 7

Burns are prone to polymicrobial infections requiring broad-spectrum coverage, and local wound cultures should guide therapy when available 3
Topical antimicrobial agents, such as mupirocin ointment or retapamulin ointment, can be considered in addition to systemic therapy for limited burn areas 1, 2