Testing the Safety of the Nature Based Microbial Exposure with Atopic Dermatitis Patients -- A Randomized, Placebo Controlled, Double-Blinded Pilot Trial

Biodiversity hypothesis posits that it is beneficial for human health to be in contact to microbial biodiversity, and loss of this contact leads to immune-mediated diseases like atopy. Based on this hypothesis, we wanted to study if a lotion containing highly diverse natural microbes is a safe and feasible way to administer nature exposure to humans, and to study the effects of the exposure on the skin. We recruited two groups: 15 people with healthy skin and 12 people with atopic dermatitis. The healthy people were divided to the three groups that used twice daily a lotion containing: 1) 10 % of live microbial extract; 2) 10 % inactivated microbial extract; 3) placebo. The people with atopic dermatitis used a lotion containing 1 % of inactivated microbial extract in one side of their body and a placebo lotion in another side. The daily use of the lotion containing diverse microbial extract was well tolerated by both healthy and atopic people. Microbial extract in lotion did not change the relative abundance of Staphylococcus on healthy skin in 14 day-trial and did not change atopic eczema severity, transepidermal water loss or erythema on atopic skin compared to placebo during 28-day trial. Atopic dermatitis patients can benefit from the overall effect of moisturizing lotion and the microbial extract, which together down-regulated pro-inflammatory IL-1{beta}, IL-22, IL-33 cytokines, and antimicrobial peptide hBD-2 on atopic lesions indicating enhanced tolerance and mitigation of eczema. Nature exposure by microbial extract in lotion could complement current atopic dermatitis treatments.