Probiotic Supplementation to Prevent Diaper Dermatitis in Antibiotic-Treated Neonates: Secondary Analysis of a Randomised Controlled Trial

Background/Objectives: Diaper dermatitis (DD) is a common dermatological condition that is often exacerbated by antibiotics. Probiotics may restore microbiota balance and influence the incidence of DD. This study aimed to evaluate whether 6 weeks of Limosilactobacillus (L.) reuteri DSM 17938 supplementation during and after antibiotic treatment affects the incidence of DD. Methods: A secondary analysis of a randomised, double-blind, placebo-controlled trial that included 89 term neonates treated with antibiotics during the first 3 weeks of life was conducted. Neonates were assigned to receive either a probiotic supplement or a placebo for a total of 6 weeks. DD incidence, onset of DD, and skin care data were collected for 87 infants. Faecal samples were collected 6 weeks after study enrolment to analyse the composition of gut microbiota. Results: Twenty-four (28%) infants developed DD, of whom six (25%) had fungal DD. There was no significant difference in the incidence of DD or fungal DD between the probiotic and placebo groups (30% vs. 25% and 7% in both groups, respectively). Probiotic supplementation had no significant effect on the gut microbiota composition or diversity. In an exploratory binary logistic regression analysis based on six fungal DD events, probiotic supplementation was not associated with fungal DD, whereas breastfeeding was associated with lower odds of fungal DD; however, the overall model was not statistically significant, and this finding should be interpreted with caution because of the small number of events. Conclusions: In this exploratory secondary analysis, supplementation with L. reuteri DSM 17938 was not associated with a reduced incidence of DD or alterations in gut microbiota composition in antibiotic-treated neonates. Breastfeeding was associated with lower odds of fungal DD; however, this finding should be confirmed in larger, adequately powered studies.