Background: Over the past 20 years, major concerns have been repeatedly expressed over antibiotic-resistant acne in Europe and in the U.S.A. However, the clinical significance of these resistance patterns is poorly defined so that topical antibiotics remain one of the cornerstones of acne management.
Objectives: To determine whether we are facing decreased efficacy of topical formulations of erythromycin and clindamycin in clinical trials of therapeutic interventions for acne.
Methods: To review systematically the results of the clinical trials investigating topical formulations of erythromycin and clindamycin for the treatment of inflammatory acne and to establish whether or not there is a decrease in the efficacy of these topical antibiotic formulations since their widespread introduction in the mid 1970s.
Results: Of the 50 eligible controlled trials identified using a systematic electronic database search strategy, 45 (90%) incorporated a lesion count, making comparison across trials possible. Analysis of clinical studies investigating the effect of topical erythromycin in acne patients indicates a significant decrease in the effect of this antibiotic on inflammatory and noninflammatory lesion count over time (r = -2.140, P = 0.001 and r = -2.032, P = 0.001, respectively). Efficacy of topical clindamycin remained stable during the study period.
Conclusions: There is a gradual decrease in the efficacy of topical erythromycin in clinical trials of therapeutic intervention for acne, which is probably related to the development of antibiotic-resistant propionibacteria.