[Probiotic baths for atopic dermatitis]

The importance of the skin microbiome in the pathogenesis of atopic dermatitis (AD) is gaining increasing attention in current research and offers opportunities for new innovative treatment options.

This study investigated the efficacy of a probiotic bath additive on clinical symptoms and skin microbiome of patients with AD.

The study was randomized and double-blind: 22 patients applied a 10-min partial bath with 4.5 × 10⁹ or 9 × 10⁹ colony-forming units (CFU) of viable lactic acid bacteria per liter daily over a period of 14 days. The clinical symptoms were documented using the SCORing Atopic Dermatitis (SCORAD) index and a patient questionnaire at day 0, day 7 and day 14. In addition, skin swabs were taken for subsequent nucleic acid extraction for quantitative Staphylococcus aureus polymerase chain reaction and microbiome analysis using amplicon sequencing.

Comparable efficacy was documented in both treatment groups: Probiotic baths with a concentration of 4.5-9 × 10⁹ CFU/liter led to a significant reduction in SCORAD scores (start of study: 63.04) and local SCORAD (14.68) on day 7 (SCORAD 47.09, local SCORAD 10.99) and day 14 (SCORAD 35.26, local SCORAD 8.54). Furthermore, the patient-assessed parameters skin dryness and itching improved significantly over the treatment period. At the same time, the mean gene copy number of S. aureus decreased by about 83% and microbiome analyses showed an increase in the richness of the bacterial community.

Topical application of a probiotic bath represents a promising supportive treatment option for AD that alleviates existing dysbiosis.