IGHE and food allergy: Food allergy is defined as an immune-mediated adverse reaction to food proteins and it is generally classified as immunoglobulin E (IgE)-mediated (see IgE-mediated food allergy article in this supplement), mixed IgE- and non-IgE-mediated (e.g., eosinophilic gastrointestinal disorders), and non-IgE-mediated [1–3].