The Effectiveness of Probiotics in Psoriasis: An Umbrella Review

Background: Psoriasis is an immune-mediated inflammatory skin condition that is chronic and causes a great deal of disease burden, especially for those affected in their most productive years. Gut microbiota, immune parameters and, in turn, psoriasis symptom improvement have recently been associated with the use of probiotics in several different studies. Objectives: This study aims to conduct an umbrella review of systematic reviews and meta-analyses of the effectiveness of probiotic supplementation as a possible adjuvant in the treatment of psoriasis. Methods: This umbrella review is listed in the PROSPERO database (registration number CRD420251130518) and was referenced according to the PRISMA 2020 guidelines. The data were obtained after a systematic search of the literature in Cochrane, Scopus and PubMed. The quality of the methodology was evaluated using the AMSTAR 2 tool; the overlap was evaluated with the corrected covered area (CCA) method. Discussions: Five systematic reviews and meta-analyses were included, covering hundreds of adult psoriasis patients. The probiotics studied consisted of both single-strain and multistrain formulations, sometimes combined with prebiotics. Probiotics are associated with significantly reduced Psoriasis Area and Severity Index (PASI) scores, increased PASI 75 response rates, lowered inflammatory biomarkers (CRP, TNFα, IL-6) and improved Dermatology Life Quality Index (DLQI). Greater effectiveness was found with multistrain probiotics, treatment duration of ≥ 12 weeks and studies conducted in Asia. Most studies reported good safety and minimal side effects. However, a high overlap among included reviews was observed (CCA = 38.64%), which should be considered when interpreting the findings and their limitations. Conclusions: Probiotics, particularly multistrain formulations, show potential as a safe and effective adjuvant therapy for reducing psoriasis severity and improving patient quality of life. Further clinical trials are needed to identify the most effective strains and optimal duration of treatment.