Improvement was mainly regarding quality of life (SMD −2.30, 85% CI −3.93 to −0.67, p = 0.006), while no effect was shown on rhinitis symptoms (SMD −0.34, 95% CI −0.62–0.07; p = 0.13) or total IgE levels (SMD 0.01, 95% CI −0.17–0.19, p = 0.88), and for antigen-specific IgE (SMD 0.09, 95% CI −0.44–0.62, p = 0.74) in the placebo group compared to the probiotic. Here, IGHE is linked to rhinitis.