Topical probiotic Lactobacillus lactis treatment in atopic dermatitis: a placebo-controlled pilot study on tolerability and efficacy

Introduction Microbiome-targeted treatments have been investigated in atopic dermatitis (AD). We aimed to investigate the tolerability and efficacy of probiotic Lactobacillus lactis lysate cream in AD. Methods A total of 13 patients with mild-to-moderate AD were treated with differently concentrated probiotic creams (3, 10, and 30%) for 4 weeks. The severity of AD [Eczema Area and Severity Index (EASI) and Investigator Global Assessment (IGA)], epidermal barrier function (TEWL), and the impact of AD [Dermatology Life Quality Index (DLQI), Patient-Oriented Eczema Measure (POEM), Atopic Dermatitis Control Tool (ADCT), and pruritus and sleep disturbance visual analog scale (VAS)] were measured at baseline (BL) and at 4 and 8 weeks. Comprehensive clinical patient data and laboratory values, including blood eosinophil count, total serum IgE levels, and specific IgEs to aeroallergens, were obtained. Results Comparison of the treatment groups and longitudinal comparisons at various time points showed no significant differences regarding AD severity (EASI, p = 0.76, CI: 0.65–1.00), epidermal barrier dysfunction (TEWL, p = 0.37, CI: 0.19–0.73), or patient-reported subjective impact of AD (DLQI, p = 0.76, CI: 0.65–1.00; POEM, p = 0.76, CI: 0.35–0.88; ADCT, p = 0.72, CI: 0.65–1.00; pruritus VAS 0.67, CI: 0.55–1.00; sleep disturbance VAS, p = 1.00, CI: 0.79–1.00) between different probiotic lysate concentrations and placebo. The probiotic lysate cream was well-tolerated, and there were no significant adverse effects. The limitations of the study were the small patient cohort and group sizes. There was also a relatively short follow-up, and no evaluation of long-term effects was conducted. Discussion In our patient cohort, topical probiotic L. lactis lysate cream showed good tolerability, but it did not show efficacy in the treatment of mild-to-moderate AD. Although topical probiotics have been reported to be effective in a limited number of studies, more placebo-controlled clinical studies are needed to explore their potential role in the treatment of AD. Clinical trial registration https://eudract.ema.europa.eu , Identifier EudraCT 2020-000514-15.