Randomised, controlled, double-blind trials that compared probiotics with placebo for the prevention or treatment of atopic dermatitis were eligible for inclusion. For treatment the primary outcomes were: reductions in severity of atopic dermatitis; changes in cytokines at the end of treatment and for children at four or eight weeks after the end of treatment. For prevention the participants of interest were pregnant women or children at high risk of atopic dermatitis and the outcome was development of atopic dermatitis. Secondary outcomes were changes in faecal lactobacilli, markers of intestinal barrier function and plasma lipids.
Included studies of treatment were mostly in infants (less than 18 months old), although a few included children up to the age of 13; participants had either moderate to severe atopic dermatitis, atopic eczema, suspected cows milk allergy, general atopic dermatitis or atopic eczema/dermatitis syndrome. Included studies of prevention were of infants (aged 0 to 12 months), pregnant or lactating women with a family history of atopic dermatitis and their infants. Probiotic treatments varied between studies.
The authors stated neither how studies were selected for the review nor how many reviewers performed the selection.