IgE-mediated wheat allergy is a growing allergy problem in children, and affected children can predict with immediate-type allergic reactions to the extent of anaphylactic shock. Current diagnostic methods based on crude wheat extract are inaccurate and unreliable. Besides, these children are managed by a passive wait-and-see approach that reflect the natural history of wheat allergy. Nonetheless, a significant proportion of wheat-allergic children have persistent disease until school-age and adolescence. There is an unmet need for designing effective and safe immunotherapeutic strategy for wheat allergy. This study aims to investigate performance of allergy tests based on crude wheat and wheat allergens as measured using both quantitative and functional IgE-based assays for diagnosing IgE-mediated wheat allergy; and to compare efficacy and safety of different dosages of wheat oral immunotherapy (OIT) for treating these paediatric patients. For the initial part, this study will recruit children with immediate-onset adverse reactions after wheat ingestion for different allergy tests, with their wheat allergy ascertained by the gold-standard double-blind, placebo-controlled food challenge. The investigators will then recruit the wheat-allergic children into a randomized, double-blind, parallel-group clinical trial with low-dose and standard-dose wheat OIT for 12 months. The main outcomes include the diagnostic performance of different conventional and novel allergy tests for challenge-confirmed wheat allergy and the rates of desensitization and sustained unresponsiveness achieved by the two dosing regimens of wheat OIT.