The effects of topical antimicrobial-corticosteroid combination therapy in comparison to topical steroids alone on the skin microbiome of patients with atopic dermatitis

Summary: Abstract Body: Background: Atopic dermatitis (AD) is a chronic recurrent inflammatory skin disease with a complex pathogenesis including a dysbiosis of both the bacterial and fungal skin microbiome. Treatments for reshaping the skin microbiome may have better therapeutic results, such as antimicrobial drugs and antimicrobial-corticosteroid combination therapy. Objective: We aim to analyze the different therapeutic responses between antimicrobial-corticosteroid combination and corticosteroids alone on improving the skin microbiome and skin barrier of AD patients. Methods: A total 40 patients with mild-to-moderate AD from August 2023 to July 2024 were randomly assigned (1:1) to receive two kinds of treatment. Skin swabs were collected from the lesional sites and nearby nonlesional sites at baseline, after topical medication treatment and 2 weeks post-treatment, and were analyzed by DNA sequencing of the fungal internal transcribed spacer (ITS)1–5 rDNA gene and the V3V4 region of the bacterial 16S rRNA gene. Results: According to our research analysis, both topical steroids alone and combination treatment of steroids and antimicrobials effectively improved the severity of AD and repaired skin barrier. AD lesions were characterized by a decreased sebum level, lower abundance of Cutibacterium and a higher abundance of Staphylococcus. A combined topical treatment with an antimicrobial and steroid showed better responses in increasing skin sebum level and restoring the skin bacterial microbiome, whereas topical steroid alone did not improve skin dysbiosis. Conclusion: A combined therapy with antimicrobial and steroid helps to recover the skin microbiome. Further studies are necessary to explore the therapeutic effects of treatments aiming at balancing the microbiome. Ruojun Wang¹, Tingting Li¹, Peixin Zhang¹, Ruoyu Li¹ 1. Peking University First Hospital, Beijing, China. Innate Immunity, Microbiology, and Microbiome