The Crosstalk between the Gut Microbiota Composition and the Clinical Course of Allergic Rhinitis: The Use of Probiotics, Prebiotics and Bacterial Lysates in the Treatment of Allergic Rhinitis.

Although massive progress in discovering allergic rhinitis (AR) aetiology has been made in recent years, its prevalence is still rising and it significantly impacts patients' lives. That is why further and non-conventional research elucidating the role of new factors in AR pathogenesis is needed, facilitating discoveries of new treatment approaches. One of these factors is the gut microbiota, with its specific roles in health and disease. This review presents the process of gut microbiota development, especially in early life, focusing on its impact on the immune system. It emphasizes the link between the gut microbiota composition and immune changes involved in AR development. Specifically, it elucidates the significant link between bacteria colonizing the gut and the Th1/Th2 imbalance. Probiotics, prebiotics and bacterial lysates, which are medications that restore the composition of intestinal bacteria and indirectly affect the clinical course of AR, are also discussed.