[Gut microbiota and allergic diseases]

Incidence of allergic diseases continues to increase, particularly among children, and has become an important public health concern. As a key link connecting environmental exposure, immune development, and susceptibility to allergic diseases, the gut microbiota has emerged as an important focus of related research. The gut microbiota plays a crucial role in immune system maturation during early life, establishment of immune tolerance, and maintenance of mucosal barrier integrity. Gut dysbiosis may contribute to the occurrence and progression of allergic diseases through multiple mechanisms, including reduced metabolite production, promotion of Th2-type immune skewing, impaired T-cell induction, and disruption of epithelial barrier function. Furthermore, the gut microbiota participates in allergic disease development through the "gut-skin axis" "gut-nose axis", and "gut-lung axis". Although different allergic phenotypes exhibit distinct clinical manifestations, they share certain common characteristics, including reduced microbial diversity, depletion of key commensal bacteria, and insufficient immune tolerance. Investigation of gut microbiota and metabolic characteristics in patients with allergic diseases, as well as their roles and clinical implications in disease pathogenesis, may provide a theoretical basis for early prevention, risk identification, and precision microbiome-based interventions for allergic diseases.