Hello, Thank you for posting your query on HCM. I appreciate your concern for your mother. Food allergy is an immune system reaction that occurs soon after eating a certain food. Even a tiny amount of the allergy-causing food can trigger signs and symptoms. The most common food allergy signs and symptoms include: Tingling or itching in the mouth Hives, itching or eczema Swelling of the lips, face, tongue and throat or other parts of the body Wheezing, nasal congestion or trouble breathing Abdominal pain, diarrhea, nausea or vomiting Dizziness, lightheadedness or fainting In some people, a food allergy can trigger a severe allergic reaction called anaphylaxis. This can cause life-threatening signs and symptoms, including: Constriction and tightening of airways A swollen throat or the sensation of a lump in your throat that makes it difficult to breathe Shock with a severe drop in blood pressure Rapid pulse Dizziness, lightheadedness or loss of consciousness. This is a medical emergency and she should go to the nearest hospital if she gets an symptom suggestive of anaphylaxis. Food allergy should not be confused with food intolerance which is much more common and is a less serious condition that does not involve the immune system.In food intolerance one may be able to eat small amounts of problem foods without a reaction. By contrast, in a true food allergy, even a tiny amount of food may trigger an allergic reaction. Because a food intolerance may involve some of the same signs and symptoms as a food allergy does like nausea, vomiting, cramping and diarrhea , people may confuse the two. There are skin tests and blood tests to detect the foods your mother may be allergic to. A specialist in Internal Medicine or an allergy specialist will be able to arrange that. If you have further query, I am available. Best wishes for your mother s good health. Dr. Noble Zachariah