The World Allergy Organisation agreement on nomenclature does not include the term "intolerance". Although allergists avoid using the term, gastroenterologists and lay persons use it freely.¹²

Instead, the WAO categorises hypersensitivities as follows:¹²

• Non-allergic hypersensitivity which is not immunological but reproducible
• Allergic hypersensitivity or allergy which is immunologically mediated; this is further divided into IgE-mediated allergy and non-IgE-mediated allergy that is immunologically mediated.

It has been proposed that the term intolerance should be "restricted to the incapacity to fully digest carbohydrates, mainly disaccharides, of which lactose is the most important one". In addition, "an adverse reaction to food should be called food hypersensitivity ... When immunologic mechanisms have been demonstrated, the appropriate term is food allergy, and, if the role of IgE is highlighted, the term is IgE- mediated food allergy".¹²