Effect of Combined Probiotics and Vitamin D on Symptoms of Allergic Rhinitis

Inclusion Criteria: Confirmed diagnosis of AR based on clinical history and specific IgE testing or will be screened for eligibility by the modified Mini Rhino-conjunctivitis Quality of Life Questionnaire (Mini RQLQ). Persistent rhinitis symptoms for at least two consecutive years. Presence of two or more AR symptom domains, including sneezing, watery rhinorrhea, nasal itching, and nasal congestion, with symptoms persisting or accumulating for more than 1 hour daily with \> 2 scores without taking medication. Symptoms may be accompanied by ocular manifestations such as eye itching, tearing, and redness Voluntarily and in writing, sign an informed consent form agreeing to participate in this study and able to complete the study as required by the trial protocol. Vitamin D insufficiency or deficiency. Deficiency: \< 20 ng/mL (\< 50 nmol/L), Insufficiency: 20-29 ng/mL (50-75 nmol/L) Exclusion Criteria: Use of systemic corticosteroids, immunosuppressive therapy, or medications affecting the gut microbiota (antimicrobials, probiotics, prebiotics, intestinal mucosal protective agents, etc.) within 4 weeks prior to screening. Regular use of probiotics, prebiotics, or vitamin D supplements within 6 months prior to screening. History of or concurrent use of medications or supplements that alter serum 25(OH)D levels, such as barbiturates, bisphosphonates, sulfasalazine, anticonvulsants, antiretrovirals, omega-3 supplements, or ketoconazole. Diagnosed with pulmonary tuberculosis, allergic asthma, chronic obstructive pulmonary disease (COPD), mast cell activation syndrome, or other respiratory diseases requiring treatment. Coexisting conditions such as nasal polyps, severe nasal septum deviation, severe gastrointestinal diseases (e.g., severe diarrhea or inflammatory bowel diseases), metabolic syndrome (e.g., obesity, dyslipidemia, hypertension, diabetes), or chronic systemic diseases or malignancies. History of autoimmune diseases or chronic inflammatory conditions. Sinusitis, otitis media, or respiratory tract infections or upper respiratory infections within 14 days of the study start. Known hypersensitivity or allergy to any component of the probiotics or other study interventions. Physical signs or symptoms suggestive of renal, hepatic, or cardiovascular disease. Pregnant or lactating women.