Urticaria is a chronic allergic inflammatory disorder. Genetic and environmental factors, such as exposure to allergens and microbes, have a detrimental role in the development of chronic urticaria. Vitamin D also has an important role in urticaria. Lower sera vitamin D level was observed in patients that developed urticaria. Vitamin D binding protein (DBP) bound to vitamin D and regulated its metabolites in the circulation. Moreover, vitamin D receptors (VDR) have been identified on nearly all cells of the immune system. It may contribute to maintenance of intestinal barrier function by preventing increased intestinal permeability, dysbiosis, inflammation, and a lack of immune tolerance in the gut.~The investigators plan to design a double-blind trial to evaluate the role of human microbiome and vitamin D in the development of urticaria. We will enroll children with chronic urticaria (CU) and age and gender matched healthy children,and collected their venous blood and microbiome samples of nasal and anal swab. Then, CU subjects will be given vitamin D or placebo for 6 months in a randomized, double-blind way. After six months of follow-up, their blood, nasal cavity, and intestinal bacterial samples were taken. All microbial analysis, allergen detection, vitamin D concentration, VDR, DBP genotype will be analyzed by the core laboratory and bioinformatics center of CMUH.~The investigators believe this study can answer the cause-effect relationships of microbiota and vitamin D in the development of CU, and design a microbiota-related preventive and treatment strategy.
A double-blind study to evaluate the role of human microbiome and vitamin D in the development of urticaria.