Therapeutic effectiveness of probiotics for atopic dermatitis: A systematic review and meta-analysis of randomized controlled trials with subgroup analysis.

BACKGROUND: The effect of probiotics in the treatment of atopic dermatitis (AD) is inconclusive, partially due to the heterogeneities of AD. OBJECTIVE: The aim of the present study was to investigate the efficacy of probiotics in the treatment of AD with a subgroup analysis according to country, severity of AD, duration of supplementation, and probiotic strain. METHODS: Original articles reporting the therapeutic efficacy of probiotics for AD were identified by searching PubMed, Cochrane Library databases, and Embase from inception to September 30, 2022. RESULTS: This meta-analysis included 1,382 patients with AD from 25 randomized controlled trials. Probiotic supplementation was effective for the treatment of AD, reflected in a significant decrease in the SCORing Atopic Dermatitis (SCORAD) index (SMD, -4.0; 95%CI, -7.3 to -0.7). The subgroup analysis showed a significant therapeutic effect for AD among patients with mild or moderate AD (SMD, -1.4; 95%CIs -2.2 to -0.7), in those supplemented for more than three months (SMD, -5.1; 95%CIs -9.7 to -0.4), and in those supplemented with a probiotic that contained Lactobacillus spp. strains combined with or without other strains (SMD, -4.4; 95%CIs -8.0 to -0.8). In addition, the therapeutic effects of probiotics showed differences according to country and geographic region. CONCLUSIONS: Probiotics can be beneficial for the treatment of AD, and their therapeutic effect may be individually tailored to improve it based on the severity of AD, strain of probiotics, duration of supplementation, and geographic region.