Study of the Effect of Combined Use of Vitamin D in Low-dose-oral immunotherapy for Children with Cow's Milk Allergy

INTERVENTION: D019587 The intervention will include the addition of vitamin D supplements to standard therapy. Intervene in a double‐blind design with placebo control. vitamin D CONDITION: Cow's milk allergy D016269 PRIMARY OUTCOME: Percentage of subjects with a positive oral food challenge test (OFC) after 6 months SECONDARY OUTCOME: Secondary efficacy endpoints; 1) Specific IgE and IgG4 levels before, 3 months after, and 6 months after the start of the study; 2) Vitamin D levels before the start of the study, 3 months after the start of the study, and 6 months after the start of the study; ; Secondary safety endpoints; 1) Specific allergic symptoms and the number of times they occurred during continuous intake of small amounts of milk; 2) Allergy‐inducing symptoms and treatment details of the oral challenge test (2.5 mL of milk) to be conducted 6 months after the start of intake of the study drug ; 3) Exacerbation of allergic comorbidities (atopic dermatitis, bronchial asthma, allergic rhinitis, allergic conjunctivitis) and drugs used; 4) Evaluation of vitamin D excess after three months and si Xmonths of the start of the study; 5) Number and percentage of adverse events (fever, respiratory tract symptoms, gastroenteritis symptoms) and serious adverse events that occurred during the study period INCLUSION CRITERIA: 1) Children 3 to 8 years of age with cow's milk allergy at the time of consent 2) A confirmed diagnosis of IgE‐dependent cow's milk allergy (symptoms eliciting an allergic immediate reaction to cow's milk ingestion) 3) Blood vitamin D concentration less than 30 ng/mL before the start of the study 4) Children who can make regular visits to Chiba University Hospital or who live near an emergency hospital 5) Patients who have received a thorough explanation of their participation in this study and who have obtained the free and voluntary written consent of the patient and the patient's surrogate after fully understanding the study.