Facial Skin Microbiome in Patients With Moderate-to-Severe Acne Vulgaris Treated With Isotretinoin

Acne vulgaris is associated with changes in the facial skin microbiome, but longitudinal microbiome changes during isotretinoin therapy remain incompletely understood. This prospective observational cohort study aims to characterize the facial skin microbiome in patients with moderate-to-severe acne vulgaris before and during isotretinoin treatment and to compare microbiome profiles with healthy individuals. Participants with moderate-to-severe acne vulgaris receiving standard-of-care oral isotretinoin will be followed prospectively. Facial skin swab samples will be collected before treatment and at scheduled follow-up visits during therapy. Healthy volunteers without acne will provide a single facial skin swab for comparison. Bacterial communities will be analyzed using 16S rRNA gene sequencing, and clinical severity will be assessed using validated acne severity scores and lesion counts. The study will evaluate changes in microbial diversity, bacterial composition, and the relative abundance of acne-associated microorganisms during isotretinoin treatment. Associations between microbiome changes and clinical improvement will also be explored. Results are expected to improve understanding of the role of the skin microbiome in acne and provide evidence for future microbiome-based therapeutic strategies.