Topical Lactobacillus plantarum as a Skin Barrier Repair and Sebum Regulation in Pediatric Atopic Dermatitis: A Randomized Controlled Trial

Atopic dermatitis (AD) is a chronic inflammatory skin condition common in children, marked by impaired skin barrier function, reduced ceramide levels, and altered lipid composition. This randomized, double-blind controlled trial aimed to evaluate the effect of topical Lactobacillus plantarum (LP) lotion on ceramide levels, transepidermal water loss (TEWL), and sebum production in pediatric AD. A total of 46 patients received LP lotion (1000 CFU/g) on the left forearm and placebo on the right, applied twice daily for four weeks. Ceramide levels were measured using tape-stripping and ELISA; TEWL and sebum were assessed at baseline, week 2, and week 4. The LP group showed a non-significant increase in ceramide levels compared to the control (13.45 ± 37.58 vs. −2.50 ± 34.01; p=0.138) and a greater reduction in TEWL (−9.60 ± 6.39 vs. −4.40 ± 2.27; p=0.740). A significant increase in sebum production was observed in the LP group (p=0.016). No adverse effects were reported. These findings suggest that topical LP may be a safe and effective adjunctive therapy for improving skin barrier function and sebum regulation in pediatric AD.