Short-Course Co-Trimoxazole for Impetigo Treatment

Mark V. Dahl, MD

Oral co-trimoxazole was noninferior to intramuscular benzathine benzylpenicillin for improving or healing lesions in 7 days.

Impetigo afflicts over 100 million children worldwide. In remote, indigenous Australia, the prevalence is 10% to 70%, and severity gauged by numbers of lesions is high. Intramuscular benzathine benzylpenicillin effectively treats impetigo in tropical, high-prevalence settings, but injections are painful, and resistant strains of Staphylococcus aureus are unaffected.

In a noninferiority, open-label study, 508 children with severe impetigo (>5 lesions) were randomized to a single intramuscular benzathine benzylpenicillin injection, oral co-trimoxazole (trimethoprim/sulfamethoxazole) daily for 5 days, or oral co-trimoxazole, a half dose twice daily for 3 days. Lesions were photographed at 0, 2, and 7 days; reviewers were blinded to which of a pair of photographs was taken first. Success was defined as improved or healed lesions on day 7 compared with day 0.

Co-trimoxazole was noninferior to benzathine benzylpenicillin in achieving treatment success (absolute difference, 0.5%; 95% confidence interval, -6.2–7.3). Outcomes were similar between co-trimoxazole groups. Overall, 10% of lesions healed, 80% improved, 3% were unchanged, and 5% were worse. Cultures isolated S. aureus from 81% of patients, Streptococcus pyogenes from 90%, and both from 74%. Isolates were virtually always sensitive to both benzathine benzylpenicillin and co-trimoxazole. Methicillin resistance was detected in 13% of isolates.

Citation(s):

Bowen AC et al. Short-course oral co-trimoxazole versus intramuscular benzathine benzylpenicillin for impetigo in a highly endemic region: An open-label, randomised, controlled, non-inferiority trial. Lancet 2014 Aug 27; [e-pub ahead of print].