True food allergy and food intolerance can have similar clinical manifestations: redness of the skin and mucous membranes, itching, swelling, rash, and indigestion. The difference between them lies in the mechanisms of origin and development.
In the presence of an allergy, there is always a clear connection: you barely bit the allergen, and the clinical symptoms – swelling, redness, itching – immediately appeared. With food intolerance, the reaction does not always occur immediately (for example, after a few hours after drinking milk, the stomach hurts), and the person himself may not feel the relationship between the product and the body’s reaction to it. Often, even a doctor, communicating with a patient, cannot always immediately distinguish one from the other. Laboratory diagnostics allows you to make an accurate diagnosis: you need to donate blood for specific immunoglobulins E (sIgE) to food products. If they are found, then a true food allergy is confirmed. If not, a food intolerance may be suspected.