Beyond The Gut: Therapeutic Applications Of Probiotics And Postbiotics In Allergic And Dermatological Disorders

The human microbiome is increasingly recognized as a systemic regulator of immunity and inflammation, extending its influence far beyond the gastrointestinal tract. In allergic and dermatological disorders, which often involve immune dysregulation and epithelial barrier defects, the microbiota and its metabolites have emerged as novel therapeutic targets. Probiotics (live microorganisms) and postbiotics (non-viable microbial products or metabolites) are gaining traction for their potential to modulate immune responses, restore barrier function, and alleviate inflammatory symptoms. This systematic review aims to synthesize current evidence on the therapeutic applications of probiotics and postbiotics in allergic and dermatological diseases, focusing on their mechanisms of action, clinical efficacy, safety, and future directions in translational medicine. Following PRISMA guidelines, a comprehensive literature search was conducted in PubMed, Scopus, Web of Science, and ClinicalTrials.gov from January ۲۰۱۰ to May ۲۰۲۵. Search terms included “probiotics,” “postbiotics,” “atopic dermatitis,” “eczema,” “allergy,” “asthma,” “rhinitis,” and “skin microbiome.” Randomized controlled trials (RCTs), systematic reviews, and meta-analyses in English were included. Data were extracted on intervention type, population, dosage, outcomes, and adverse effects. Risk of bias was assessed using Cochrane RoB ۲.۰ tools. A total of ۷۲ studies met inclusion criteria, including ۳۶ RCTs, ۱۸ observational studies, and ۱۸ reviews/meta-analyses. Oral and topical probiotics demonstrated moderate efficacy in preventing or ameliorating atopic dermatitis (AD), allergic rhinitis, and some chronic inflammatory dermatoses. Specific Lactobacillus and Bifidobacterium strains were associated with improved SCORAD and EASI scores. Postbiotics, though fewer in number, exhibited comparable immunomodulatory benefits with superior stability and safety. Heterogeneity in study design, strain selection, and outcome measures limited meta-analytic interpretation. Evidence supports the therapeutic and preventive potential of probiotics and postbiotics in certain allergic and dermatologic conditions, especially when used as adjunctive therapies. Postbiotics offer particular promise for their stability, reproducibility, and low infection risk. Standardized definitions, strain-specific research, and mechanistic biomarker studies are essential for advancing microbiome-based therapeutics in dermatology and allergy.

کلیدواژه ها:

Probiotics ، Postbiotics ، Atopic dermatitis ، Allergic diseases ، Skin microbiome