Randomized double-blind comparative study on the effect of bifidobacteria on the induction of resistance to hen's egg allergy oral immunotherapy

INTERVENTION: Bifidobacteria, twice a day, 52weeks dexistrin , twice a day, 52weeks CONDITION: hen's egg allergy PRIMARY OUTCOME: Acquisition rate of egg tolerance at 52 weeks after intervention started SECONDARY OUTCOME: Egg tolerance acquisition rate at 48 weeks after intervention started; Objective indicator (blood: change in eosinophil count, total IgE, antigen specific IgE (egg egg: egg white, egg yolk, ovomucoid), antigen specific IgG4 (egg white, ovomucoid), basophil stimulation test (OVM) , Faeces: intestinal flora, calprotectin, skin,prick test); Side reaction rate on oral immunotherapy; Safety assessment (incidence of adverse events) INCLUSION CRITERIA: a) Obvious hen's egg allergic patients b) Patients who are 5 years or older at the start of the study c) After receiving sufficient explanation for the participation of this study, patients who obtained document consent with the free will of the patient himself or the substitute person with sufficient understanding