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Food Allergy or Intolerance?

While the symptoms of a food allergy & intolerance can look very similar, both conditions have distinct characteristics and call for different treatments.

Food Allergy or Intolerance?

Written by Dr. Purvi Shah

Nearly 15 million Americans have food allergies. However, most people use the term “food allergy” loosely. There are distinct differences in symptoms/reactions and the pattern of symptoms between food allergies and food intolerance.

Food intolerance is a type of a “food reaction” – not a true food allergy. The symptoms usually occur within 4-24 hours after eating certain foods. They are usually abdominal symptoms – bloating, cramping, discomfort, flatulence, and loose stools. Other symptoms can be feeling lethargic or “tired all the time”.

The common foods that trigger a food intolerance reaction are dairy and wheat. There is a diagnostic test available for dairy (specifically lactose) intolerance, which can be done by a Gastroenterologist. There is no diagnostic test for wheat or other food intolerance. The truest way to diagnose food intolerance is to do an elimination diet trial for 4-6 weeks. Further evaluation with a Gastroenterologist is usually recommended.

A food allergy is caused by a specific allergic mechanism produced by our immune system that is targeted against a specific food protein allergen. This mechanism is called a specific IgE mediated allergy reaction. If someone eats a specific food that they are allergic to, they will immediately develop a constellation of symptoms within the first few hours, most commonly within the first 30 minutes. These symptoms usually include – itchy mouth, generalized itching, hives, swelling of the face, tongue, or throat; later followed by coughing, wheezing, difficulty breathing, intense vomiting and diarrhea, and sometimes shock. This reaction is life-threatening and should be treated immediately with epinephrine and Benadryl.

The common foods that cause allergies are cows milk, egg, wheat, peanut, tree nuts, shellfish, and fish. Allergies to cow’s milk, egg, and wheat are more common in children and are often outgrown later in life. Allergy to peanut, tree nuts and fish/shellfish are usually diagnosed in children and tend to persist throughout their life. However, adults can develop a new allergy to peanut, tree nuts and seafood later in life.

If you want to make sure you have a true food allergy, there are diagnostic tests available. These include skin prick testing and what’s called an IgE immunocap rast blood test. If someone has a history of an allergic reaction after eating a particular food, plus a positive skin test and/or IgE blood test, they are considered to have a true food allergy. To make sure that you or your loved one gets a clear diagnosis, these tests are best done and interpreted by board-certified Allergists. Once it is clear that there is an allergy, an Allergist/Immunologist can help manage that food allergy.

Our Allergy & Asthma specialists at Advanced Specialty Care located in Fairfield County, CT can diagnose allergies and help you manage your condition. If you suspect you or a loved one has a food allergy, visit one of our food allergy specialists in Danbury, New Milford, Norwalk, and Ridgefield.


Allergist & Immunologist Dr. Purvi Shah--Allergy & Asthma doctor in Ridgefield, Norwalk & Danbury, CTDr. Purvi Shah

Dr. Purvi Shah is an Allergy & Asthma doctor at Advanced Specialty Care, treating adult & pediatric patients in our Danbury, Ridgefield & Norwalk offices.


The Allergy & Asthma specialists at Advanced Specialty Care, Drs. Jonathan Bell, Yogen Dave, Neetu Godhwani, Purvi Shah, Cristina Vo, and APRN Michelle DiMauro, specialize in all of your family’s Allergy concerns–offering the region’s largest and longest-running Immunotherapy program. To schedule your appointment with an Allergy & Asthma Specialist at Advanced Specialty Care, with offices in Danbury, New Milford, Ridgefield & Norwalk, CT, call us at (203) 830-4700 or request your appointment today.

The Allergy & Asthma specialists at Advanced Specialty Care, with offices located in Danbury, New Milford, Ridgefield, Norwalk & Stamford, CT--Drs. Jonathan Bell, Yogen Dave, Neetu Godhwani, Purvi Shah, Cristina Vo, and APRN Michelle DiMauro.