Egg oral immunotherapy with probiotics for severe egg allergy

INTERVENTION: This study is a double‐blind, placebo‐controlled, randomized, controlled trial.The study drug (probiotics or placebo) is 1 g once daily for 1 year. The study drug for probiotics contains 0.03 g of LGG (bacteria count: 1 X10^9), 0.3 g of Bifidobacterium bifidum TMC3115 (bacteria count: 1 X10^9), and an excipient (maltodextrin) in 1 g. The protocol for oral immunotherapy with heated hen's egg powder is similar for both groups. CONDITION: D005512 food allergy ; Food Hypersensitivity PRIMARY OUTCOME: Percentage of the patients who acquired tolerance for 1/2 a heated whole egg after 12 months from start of oral immunotherapy. SECONDARY OUTCOME: Percentage of the patients who acquired desensitization to 1/8 of a heated whole egg after 12 months from start of oral immunotherapy.; Frequency of adverse reactions during 12 months.; Rates of changing egg white/ovomucoid‐specific IgE, IgG, and IgG4 levels during 12 months.; Number of infections with fever or requiring hospitalization during 12 months.; Diversity of the intestinal microbiota and change in bacterial species by 16S rRNA analysis.; Rates of changing in serum short‐chain fatty acids during 12 months. INCLUSION CRITERIA: (1) Patients between 5 and 18 years of age (2) Patients whose obvious immediate‐type allergic symptoms were induced by less than 1/8 of a heated whole egg (775 mg of egg protein) in oral food challenge (3) Patients whose consent to participate in this study has been obtained