Background: Seasonal Allergic Rhinitis (SAR) is a common condition characterized by allergy symptoms that vary with the seasons. The microbiome, including both nasal and gut microbiota, may influence allergic responses. However, there is limited understanding of how microbiome composition varies seasonally and its impact on SAR symptoms. Method: This cross-sectional study at Territory Care Hospital from March 2023 to July 2024 included 100 SAR patients. The study examined annual microbiome alterations. Nasal and gut microbiome samples using bioinformatics and 16S rRNA gene sequencing to count and classify microorganisms. To identify seasonal differences, we studied spring, summer, autumn, and winter microbial profiles. Results: The study found statistically significant microbiome composition seasonality. Staphylococcus increased significantly in the nasal microbiome in spring (p < 0.01), while Haemophilus increased in autumn (p < 0.05). In the gut microbiota, Bifidobacterium levels decreased significantly in summer (p < 0.05) whereas Lactobacillus levels increased significantly in winter (p < 0.05). These findings suggest that seasonal changes in bacterial taxonomy may affect SAR symptoms. Conclusion: The study shows significant seasonal shift in SAR patients’ nasal and gut microbiomes. These findings suggest that seasonal microbiome regulation may control SAR. Future study should examine microbiota dynamics and allergy reactions over longer time periods.

Background: Seasonal Allergic Rhinitis (SAR) is a common condition characterized by allergy symptoms that vary with the seasons. The microbiome, including both nasal and gut microbiota, may influence allergic responses. However, there is limited understanding of how microbiome composition varies seasonally and its impact on SAR symptoms. Method: This cross-sectional study at Territory Care Hospital from March 2023 to July 2024 included 100 SAR patients. The study examined annual microbiome alterations. Nasal and gut microbiome samples using bioinformatics and 16S rRNA gene sequencing to count and classify microorganisms. To identify seasonal differences, we studied spring, summer, autumn, and winter microbial profiles. Results: The study found statistically significant microbiome composition seasonality. Staphylococcus increased significantly in the nasal microbiome in spring (p < 0.01), while Haemophilus increased in autumn (p < 0.05). In the gut microbiota, Bifidobacterium levels decreased significantly in summer (p < 0.05) whereas Lactobacillus levels increased significantly in winter (p < 0.05). These findings suggest that seasonal changes in bacterial taxonomy may affect SAR symptoms. Conclusion: The study shows significant seasonal shift in SAR patients’ nasal and gut microbiomes. These findings suggest that seasonal microbiome regulation may control SAR. Future study should examine microbiota dynamics and allergy reactions over longer time periods.