Indeed, IgE positivities reveal sensitization, but clinical allergy has to be confirmed on the ground of evidence of a relationship between results of IgE test and occurrence of symptoms from exposure to the specific allergen, as well as by demonstration of concomitant inflammation in the airways as assessed by the presence of eosinophils in nasal smears and increase of FeNO [28]. This evidence concerns the gene IGHE and Allergy.