Efficacy of a probiotic supplement in patients with atopic dermatitis: a randomized, double-blind, placebo-controlled...

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.

To evaluate the efficacy of a food supplement containing selected strains of probiotics in ameliorating AD symptoms and skin conditions in adult volunteers.

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 T_0d, T_28d and T_56d, and then at T_84d (after a one-month wash-out). Inflammatory cytokine levels from skin tape stripping, sampled close to AD lesions at T_0d and T_56d, were also measured.

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 T_28d, with a positive trend up to T_56d which was maintained at T_84d.

Administration of selected probiotic strains resulted in a fast and sustained improvement in AD-related symptoms and skin conditions.