Acne and the cutaneous microbiome: A systematic review of mechanisms and implications for treatments

Abstract

Background: Acne vulgaris is a pervasive skin disease characterized by inflammation of sebaceous units surrounding hair follicles. It results from the complex interplay between skin physiology and the intricate cutaneous microbiome. Current acne treatments, while effective, have major limitations, prompting a shift towards microbiome-based therapeutic approaches.

Objectives: This study aims to determine the relationship between acne and the cutaneous microbiome, assess the effects of current treatments on the cutaneous microbiome, and explore the implications for developing new therapies.

Methods: A systematic review was performed using PubMed and SCOPUS databases within the last 10 years. Methodological quality was assessed independently by two authors. The search retrieved 1830 records, of which 26 articles met the inclusion criteria. Meta-analysis of alpha diversity change was assessed using fixed and randomized effect models per therapeutic group.

Results: Eight studies pertain to the role of the cutaneous microbiome in acne, identifying C. acnes, S. aureus and S. epidermidis as key contributors through overproliferation, commensalism, or dysbiosis. Eleven studies discuss current acne treatments, including doxycycline (1), topical benzoyl peroxide (BPO) (4), isotretinoin (2), sulfacetamide-sulfur (SSA) (2) and aminolevulinic acid-photodynamic therapy (ALA-PDT) (2), identified as modulating the cutaneous microbiome as a mechanism of efficacy in acne treatment. Seven studies discuss new treatments with topical probiotics, plant derivatives, and protein derivatives, which contribute to acne clearance via modulation of dysbiosis, inflammatory markers and diversity indexes. A meta-analysis of the effects of existing therapeutics on the cutaneous microbiome identified benzoyl peroxide as the only treatment to facilitate significant change in diversity.

Conclusions: Despite the heterogeneity of study types and microbiome classifications limiting the analysis, this review underscores the complexity of microbial involvement in acne pathogenesis. It delineates the effects of acne therapeutics on microbial diversity, abundance, and composition, emphasizing the necessity for personalized approaches in acne management based on microbiome modulation.

FIGURE 1

PRISMA diagram of the systematic study selection process.

FIGURE 2

Forest plot of standardized mean change to cohort pretreatment and post‐treatment alpha diversity in eight studies. Confidence bounds represent the 95% confidence intervals. Treatment types per study are abbreviated: benzoyl peroxide (BPO), oral doxycycline (PO Doxy) and salicylic acid (SSA). The Wongtada et al. study includes three treatment arms, which were analysed as separate results: Benzoyl peroxide (BP), retinoic acid (VVA) and a commercial cream‐gel dermo‐cosmetic (DC). Results of a fixed effect and random effect meta‐analysis are displayed with 95% confidence intervals.

FIGURE 3

Meta‐analysis results for studies using the same treatment agent. (a) Forest plot of standardized mean change to alpha diversity in 3 studies that used benzoyl peroxide for treatment. Fixed effect meta‐analysis results are shown with 95% confidence intervals. The meta‐analysis showed a significant standardized mean change (p = 0.002). (b) Forest plot of standardized mean change in alpha diversity in two studies that used salicylic acid for treatment. Fixed effect meta‐analysis results are shown with 95% confidence intervals. The meta‐analysis showed no significant standardized mean change (p = 0.381).