Probiotics as treatment for food allergies among pediatric patients: a meta-analysis.

Background: The burden of disease of food allergy is increasing worldwide. The standard of management is allergen avoidance and symptomatic treatment. Probiotics have been proposed to be beneficial for treatment and prevention of food allergy.

Objective: To determine the effectiveness of probiotic administration in treating food allergies among pediatric patients.

Methods: A systematic search of electronic medical literature databases was conducted. Manual search of the reference lists and search for unpublished articles were also done. All randomized controlled trials available from inception until February 19, 2018 were retrieved. The primary outcome of interest was relief of allergic symptoms, while the secondary outcome of interest was inducement of tolerance. Two independent authors did the search, screening, appraisal, and data abstraction. Data analysis and synthesis were done using RevMan 5.3 software. Subgroup analysis was done based on the probiotic strains and time periods in measuring the outcome. Exclusion sensitivity analysis was also done.

Results: Nine trials involving 895 pediatric patients with cow's milk allergy (CMA) were included in the review. The primary outcome of interest, relief of symptoms, was measured using the scoring index for eczema. Pooled results from two studies showed larger reduction in the scoring index among patients given probiotics, but this effect was imprecise (MD -1.30, 95% CI -3.88, 1.28). For the secondary outcome of interest, pooled results from four studies showed benefit of probiotics in inducing tolerance, but again this result is imprecise with significant heterogeneity (RR 0.58, 95% CI 0.34, 1.00). Subgroup analysis per probiotic strain showed benefit of Lactobacillus rhamnosus GG in inducing tolerance based on two studies involving infants with suspected cow's milk allergy (RR = 0.41, 95% CI 0.28 to 0.62). Another subgroup analysis showed a duration-dependent effect associated with probiotic usage, with inducement of tolerance noted after at least 2 years (RR = 0.44, 95% CI 0.29 to 0.67).

Conclusion: Analysis of available evidence shows moderate certainty that the use of probiotics can relieve symptoms of children with cow's milk allergy. The reduction in certainty is due to imprecise results. Moreover, there is low certainty that probiotics can induce tolerance among children with cow's milk allergy, due to problems of imprecision and attrition bias. In the subgroup analysis, Lactobacillus rhamnosus GG administration likely results in inducing tolerance among infants with suspected cow's milk allergy. Only studies on CMA were analyzed since no studies were found on probiotics as treatment for other types of food allergy among children.