Background: Atopic dermatitis (AD) is a multifactorial long-standing inflammatory skin disease with a high incidence worldwide in both adults and children. According to the recognized correlation between skin and intestine-the so-called "gut-skin axis"-gut unbalances can affect skin by inducing systemic inflammation and triggering dermatological diseases such as AD.
Objectives: To evaluate the efficacy of a food supplement containing selected strains of probiotics in ameliorating AD symptoms and skin conditions in adult volunteers.
Materials & methods: Eighty adult subjects showing mild-to-severe AD, skin dryness, desquamation, erythema and itching were enrolled in a randomized controlled trial to receive, for 56 days, a placebo or a mixture of lactobacilli (L. plantarum PBS067, L. reuteri PBS072 and L. rhamnosus LRH020). The latter was chosen according to the patients' production of post-biotic metabolites and B-group vitamins, anti-inflammatory and anti-oxidant capacity and anti-microbial activity. Clinical and instrumental dermatological evaluation was performed at T0d, T28d and T56d, and then at T84d (after a one-month wash-out). Inflammatory cytokine levels from skin tape stripping, sampled close to AD lesions at T0d and T56d, were also measured.
Results: Subjects receiving the probiotic mixture showed an improvement in skin smoothness, skin moisturization, self-perception, and a decrease in SCORAD index as well as in the levels of inflammatory markers associated with AD at T28d, with a positive trend up to T56d which was maintained at T84d.
Conclusion: Administration of selected probiotic strains resulted in a fast and sustained improvement in AD-related symptoms and skin conditions.
Keywords: SCORAD; adult subjects; atopic dermatitis; probiotics; randomized controlled trial.