Background: Probiotics are perceived to exert beneficial effects in the prevention and treatment of allergic diseases.
Objective: There are conflicting data from studies as to an impact on allergic sensitization and asthma.
Methods: Our prospective double-blind study randomly assigned 131 children (6-24 months old) with at least two wheezing episodes and a first-degree family history of atopic disease to 6 months of Lactobacillus rhamnosus (LGG, 10(10) colony forming units) or placebo. Atopic dermatitis and asthma-related events (e.g. need of inhalation, symptom-free days) were documented throughout the intervention and 6-month follow-up. We determined IgE, a representative panel of specific IgE, eosinophils, eosinophilic cationic protein, and TGF-beta before, at the end of intervention, and after 6 months of follow-up.
Results: There were no significant differences as to atopic dermatitis or asthma-related events. In a subgroup with antecedent allergic sensitizations, asthmatic complaints were even slightly worse. We found fewer sensitizations towards aeroallergens after 6 months of LGG (P=0.027) and after 6 months of follow-up (P=0.03). Supplementation was well-tolerated and no severe adverse events occurred.
Conclusions: In young children with recurrent wheeze and an atopic family history, oral LGG had no clinical effect on atopic dermatitis or asthma-related events, and only mild effects on allergic sensitization. This effect persisted 6 months after the cessation of the supplementation.
Trial registration: ClinicalTrials.gov NCT00490425.