Sensitization is different from an allergy. Sensitization means that the immune system is producing food-specific antibodies, but sensitization alone is not diagnostic for an allergy. In fact, people can be sensitized to foods, like tree nuts, without experiencing any symptoms upon exposure.[1] This is why a history of consistent allergic signs and symptoms after exposure to a food is a necessary component of a food allergy diagnosis.
Food intolerances are separate from food allergies and do not involve the immune system. An intolerance to a food means that a person is unable to properly digest the food, causing gastrointestinal symptoms (like bloating, nausea, and cramps).