Probiotics eased eczema in children and adults, but not in babies

Atopic dermatitis, the itchy inflammatory skin condition most people know as eczema, affects children and adults alike, and probiotics have long been floated as a way to calm it through the gut. Before this analysis, the authors describe the treatment evidence as inconclusive, with individual trials pointing in different directions. Whether any benefit differs by age, and whether infants gain anything at all, were open questions. Pooling the trials offered a way to establish how much probiotics actually move eczema severity.

The researchers searched databases through December 2013 for randomised controlled trials testing probiotics or synbiotics, meaning probiotics combined with prebiotics, in people diagnosed with atopic dermatitis. Twenty-five trials with 1,599 participants qualified for the analysis. The primary outcome was the difference in SCORAD, a standard scoring system for eczema severity, between the treatment and placebo groups. Results were analysed overall and separately for infants under 1 year, children aged 1 to 18, and adults.

Overall, probiotic treatment was linked with a SCORAD score 4.51 points lower than control, with the plausible range running from 2.24 to 6.78 points. Children aged 1 to 18 improved by 5.74 points on average and adults by 8.26 points, but the effectiveness of probiotics in infants under 1 was not proved. Synbiotics performed no differently from probiotics alone. Treatment with a mixture of different bacterial species, or with Lactobacillus species, showed greater benefit than Bifidobacterium species used alone.

This pooled result moves probiotics from an inconclusive idea towards a credible option for eczema, especially moderate to severe cases in children and adults, which is the authors' own conclusion. The infant null is notable because early-life eczema is precisely where probiotic products are often marketed. The strain findings add a practical wrinkle: not all probiotics look equal, with Lactobacillus and mixed-species products outperforming Bifidobacterium alone. Which strains, doses and durations work best remains to be pinned down by future trials.

If you or a child past infancy deal with eczema, this is a reason to think probiotics may offer a modest extra layer of relief alongside usual care rather than a replacement for it. The average improvement was a handful of points on a severity scale, so expectations should be sized accordingly. For infants, the pooled trials provide no proof of benefit, which is worth knowing given how heavily probiotics are promoted for babies.