Retapamulin: what is the role of this topical antimicrobial in the treatment of bacterial infections in atopic dermatitis?

In atopic dermatitis (AD), the stratum corneum of patients appears to have alterations that predispose them to colonization and invasion by various bacteria, most notably Staphylococcus aureus (S. aureus). This bacterial co-existence is accepted to be an important factor in AD disease activity. Exactly when to initiate antimicrobial treatment is controversial, but such intervention, when warranted, has repeatedly been demonstrated to improve the course of AD. However, the increase in antibiotic resistance presents a therapeutic challenge in the management of AD patients, which highlights the need for novel mechanism topical antibacterial agents. Retapamulin is a relatively new pleuromutilin antibiotic designed for topical use. In vitro studies have demonstrated its low potential for the development of antibacterial resistance and high degree of potency against Gram-positive bacteria found in skin infections, including many S. aureus strains that are resistant to methicillin, fusidic acid, and mupirocin. Clinical studies exploring the treatment of secondarily infected dermatitis reveal that the efficacy of topical retapamulin is comparable to a 10-day course of oral cephalexin or to topical fusidic acid. Retapamulin appears to be a much needed antimicrobial option for treating the AD population due to their common carriage of bacterial pathogens and frequency of infectious complications.