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

Overview

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.

Acne vulgaris is a chronic inflammatory disease of the pilosebaceous unit and is one of the most common dermatologic disorders worldwide. Increasing evidence suggests that acne is associated with alterations in the composition and diversity of the skin microbiome rather than the presence of a single pathogenic microorganism. However, longitudinal changes in the facial skin microbiome during isotretinoin treatment have not been fully characterized in Southeast Asian populations. This study is a prospective observational cohort conducted in Vietnam. The study includes two participant groups: patients with moderate-to-severe acne vulgaris and healthy volunteers without acne. Patients receive oral isotretinoin according to routine clinical practice and institutional treatment protocols. The study does not assign or modify treatment; investigators prospectively observe clinical and microbiome changes during routine care. Facial skin samples are collected using standardized skin swab procedures from predefined facial sites. Samples are processed for bacterial DNA extraction and 16S rRNA gene sequencing to characterize microbial communities. Sequencing data are analyzed using bioinformatics pipelines for taxonomic classification and diversity analysis. Clinical assessments include validated acne severity grading systems, inflammatory and non-inflammatory lesion counts, and evaluation of treatment response during follow-up. Healthy volunteers provide baseline microbiome samples for comparison with acne participants before treatment. The primary objective is to characterize longitudinal changes in the facial skin microbiome during isotretinoin treatment in patients with moderate-to-severe acne vulgaris. Secondary objectives include comparing baseline microbiome characteristics between acne patients and healthy individuals and exploring associations between microbiome composition and clinical treatment outcomes. Study findings may contribute to a better understanding of microbiome dynamics during isotretinoin therapy and provide a foundation for future microbiome-targeted approaches in acne management.