Abstract
Psoriasis is a chronic immune-mediated skin disease that is increasingly associated with alterations in gut microbiota through the gut-skin axis. This systematic review assessed the efficacy of probiotic supplementation in managing psoriasis. A comprehensive search was performed across PubMed, Scopus, and the Cochrane Library for studies published between 2010 and 2025. After screening 688 unique records and removing duplicates and incomplete entries, 10 studies were found relevant, and eight with accessible full texts were included for qualitative synthesis. Across included randomized controlled and observational studies, probiotic or synbiotic supplementation either alone or as an adjunct to topical or systemic therapy was associated with reductions in Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI) scores. Several included studies also reported improvements in inflammatory biomarkers and gut microbiota composition, which were narratively presented in this review. Due to heterogeneity in study designs and interventions, findings were synthesized narratively. Multistrain formulations containing Lactobacillus, Bifidobacterium, or Lactiplantibacillus plantarum consistently demonstrated clinical benefits, whereas single-strain products yielded variable outcomes. All interventions were well tolerated, with only mild gastrointestinal discomfort noted in a small minority of participants. The available evidence suggests that probiotic supplementation may reduce disease severity, improve quality of life, and support immune and barrier function in individuals with psoriasis. The therapeutic effect appears strain-dependent and more pronounced in mild-to-moderate disease. Larger, well-controlled trials with standardized probiotic strains, defined dosages, and longer follow-up are needed to clarify the long-term clinical value of probiotics as adjunctive therapy in psoriasis management.