Final answer:
The immune system mistakenly identifying certain proteins in food as harmful causes a food allergy, leading to symptoms like itching and swelling. This is distinct from food intolerance, which involves digestive issues without an immune response.
Step-by-step explanation:
The condition in question where the body's immune system reacts to substances in some foods is known as a food allergy. This reaction occurs because the immune system wrongly identifies certain food proteins as harmful, even though they are typically harmless to most people. During a food allergy reaction, the body's immune system launches an attack that can result in symptoms like itching, swelling, and difficulty breathing. This is different from food intolerance, where the immune system is not involved and the reactions are related to the digestive system—such as lactose intolerance due to the lack of lactase enzyme.