Postbiotics in Dermatology: A Literature Review of Emerging Topical Therapies for Acne, Rosacea, and Eczema

Postbiotics, defined as non-viable microbial cells and their metabolites, have emerged as topical therapies for inflammatory dermatoses and provide more clinical benefits than live postbiotics by eliminating infection risk and stability. This literature review aims to generalise existing knowledge about the effectiveness and mechanisms of action of first-line topical postbiotic treatments for acne, rosacea, and eczema. Search terms included "postbiotics" and keywords that represented the dermatological conditions of interest. Thematic synthesis was performed on the systematically extracted data. After screening, 16 studies were included in the review. Postbiotic preparations showed significant reductions in Scoring Atopic Dermatitis (SCORAD) and pruritus and improved barrier function in the skin, as well as longer remissions (p < 0.001). In acne vulgaris, postbiotics decreased inflammatory lesions by 50% to 70%, suppressed sebum secretion (42% to 72%), and stopped the growth of Cutibacterium acnes. The study concluded that topical postbiotics, reported to be effective in atopic dermatitis and acne vulgaris, have favourable safety profiles and can be integrated into treatment regimens for the aforementioned diseases. However, no interventional studies have examined rosacea, and the evidence is limited to narrative reviews in which microbiome disequilibrium remains undetermined despite a lack of clinical efficacy. Therefore, a lack of clinical trials for rosacea is a high research priority, given the substantial mechanistic rationale for this absence of high-quality pragmatic evidence.