This is owing to their potentially chronic presentation, delayed onset of symptoms, less obvious allergen link, and possibility for clinical overlap with GERD, infections, or FGIDs which are much more common in the first year of life with a reported prevalence of 25% to 77%.7,19 In addition, apart from an OFC with CM, there are currently no optimal diagnostic tests and biomarkers for non-IgE-mediated CMA.20 However, parents frequently refuse or delay OFC due to fear of a severe reaction.21 This evidence concerns the gene IGHE and infection.