In patients with food allergy, measuring sensitization to components is more informative than measuring levels of IgE to whole extracts.4, 6, 7, 8 For some allergen sources, there is a dominant component to which most sensitized subjects will react (eg, Fel d 1 is positive in almost all subjects with IgE to cat), but for others, no such dominant allergen exists (eg, sensitization to Can f 1, 2, 3, and 5 identifies less than half of those with IgE to dog).9 Here, IGHE is linked to food allergy.