Atopic dermatitis is characterised by a predominance of T helper 2 immune cells compared with T helper 1 immune cells
One underlying cause of this immunologic imbalance might be compromised gut microbiota with resultant disruption of intestinal barrier function, in turn, leading to type 2 dominant immuno-inflammation.
Indeed, it has been shown that patients with atopic dermatitis have a reduced number of butyrate-producing and propionate-producing gut bacteria.
In a double-blind, placebo-controlled trial, researchers aimed to evaluate the efficacy of probiotic supplementation for controlling atopic dermatitis symptoms and reducing the need for topical steroids.
A total of 50 children (aged 4–17 years) with moderate atopic dermatitis were randomised to take probiotics or a placebo for 12 weeks.
All subjects had been prescribed topical steroids, and all were also consuming a high-quality Mediterranean Diet (KIDMED score >7).
The probiotic provided 109 colony-forming units of a mixture of three probiotic strains in a 1:1:1 ratio: Bifidobacterium lactis CECT8145, B. longum CECT7347 and Lactobacillus casei CECT9104.
Two primary outcomes were assessed: change in SCORAD (Scoring Atopic Dermatitis) index from baseline to 12 weeks, and the proportion of days of topical steroid use within the 12 weeks of follow-up.
From baseline to 12 weeks, the SCORAD index improved in the probiotic group by 83% and in the placebo group by 24%.
The improvement in the SCORAD index in the probiotic group was significantly greater than the improvement in the placebo group (mean difference between groups = -19.2; 95% CI, -15.0 to -24.0; p<.001).
Compared with the placebo group, the probiotic group had a significant reduction in the use of topical steroids to treat flares during the 12 weeks (14.0% of days in probiotic group vs. 16.5% of days in placebo group; p<.003).
One reason for the success of this study may have been that the researchers considered several factors shown to improve the response to probiotics in atopic dermatitis: duration of treatment longer than 8 weeks, patients older than 1-year old, patients with moderate to severe (rather than mild) symptoms, and using a combination of Lactobacilli and Bifidobacteria in the mixture.
The results of this study provide good evidence for the efficacy of probiotic supplementation to reduce the need for topical steroids in moderate atopic dermatitis in children.