Pediatrics & Neonatology

Introduction Dietary supplementation with probiotics alters intestinal microflora of children and may have immunomodulatory effects in prevention of allergic diseases. The aim of this study was to evaluate the effects of Lactobacillus paracasei (LP), strain HF.A00232, as a supplementary agent to levocetirizine in treating children with perennial allergic rhinitis (AR). Methods This study was a 12-week, double-blind, randomized, placebo-controlled trial. Sixty children with AR aged 6–13 years with nasal total symptoms score (NTSS) ≥5 who fulfilled the inclusion criteria were enrolled. Patients were randomized into two groups with 28 participants receiving levocetirizine plus placebo and 32 participants receiving regular levocetirizine plus LP (HF.A00232) for the first 8 weeks, with a shift to levocetirizine as rescue treatment during the following 4 weeks. Parameters evaluated, including nasal, throat, and eye TSS (NTSS, TTSS, and ETSS, respectively), TSS and levocetirizine use, were recorded daily. Physical examinations and Pediatric Rhinoconjunctivitis Quality of Life Questionnaires (PRQLQs) were administered at each visit. In addition, blood samples were obtained for evaluation of cytokines including interleukin-4, interferon-γ, interleukin-10, and transforming growth factor-β at baseline, Week 8, and Week 12. Results The LP (HF.A00232) group had significantly lower PRQLQ scores even after discontinuing regular levocetirizine from Week 9 to Week 12 (p < 0.01). There was more improvement in individual parameters in the PRQLQ, including sneezing (p = 0.005), itchy nose (p = 0.040), and swollen puffy eyes (p = 0.038), in the LP (HF.A00232) group. No significant differences in TSS, NTSS, TTSS, ETSS, or cytokine levels were found between the two groups. Conclusion Dietary supplementation with LP (HF.A00232) provided no additional benefit when used with regular levocetirizine in treating AR in the initial 8 weeks of our study, but there was a continuing decrease in PRQLQ scores, as well as a significant improvement in individual symptoms of sneezing, itchy nose, and swollen eyes, after discontinuing regular levocetirizine treatment.