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What To Do If You Suspect A Food Allergy Or Intolerance

What To Do If You Suspect A Food Allergy Or Intolerance

With greater than 3 million US cases a year, it’s safe to say that most people know someone with a food allergy. However, despite how common food allergies are, they are not all easily diagnosed and many people suffer years before they determine what the actual cause of their uncomfortable symptoms are.

Food Allergy vs Food Intolerance

To help ease some frustration, it’s important to note the difference between a food allergy and a food intolerance. A food allergy can cause a wide range of symptoms created by the body’s immune system response to a particular food that your body sees as a threat. This typically happens within 30 minutes to 2 hours of eating. In some cases, the reaction can be severe or even life-threatening, such as in anaphylaxis.

A food intolerance, on the other hand, is usually much less severe, but can still be troublesome and scary. An intolerance is often described as the feeling of the food ‘not agreeing with you.” When your body simply does not have the ability to break down a certain food or ingredient, we call it a food intolerance.

Common Food Allergens vs Common Food Intolerances

As you can see, many foods can be either a food allergy or a food intolerance. The difference lies in the way the body reacts to the food.

Some common symptoms of a food allergy are:

  • A strange sensation in the mouth or on the lips such as itching or tingling

  • Nasal congestion, wheezing, and/or swelling of the throat

  • Gastrointestinal issues such as diarrhea, abdominal pain or nausea/vomiting

  • Dizziness, lightheadedness or even fainting

  • Rash or hives

Common symptoms of a food intolerance are:

  • Gastrointestinal discomfort including gas, heartburn, belching, vomiting or diarrhea

  • General body fatigue

  • Irritability

  • Acne

What To Do If You Suspect A Food Allergy

If you suspect a food allergy because you ate something that caused a mild reaction such as an itchy throat, hives, difficulty breathing or vomiting it is important to see a doctor before eating that food again. You may not even be sure what food or ingredient caused the reaction, but once you introduce the food allergen to your body, an immunoglobulin (IgE) begins to travel through your body via your blood and this attaches to mast cells which are found in the tissues of our bodies. This will prime your body to have a more severe reaction the next time you consume that food or food ingredient.

A doctor or an allergist will ask you a series of questions to help narrow down what could be causing a reaction, then perform a skin test to confirm the foods you need to avoid to stay healthy. A skin or scratch test is not 100% accurate nor is it recommended for someone with eczema. It can also be dangerous in the case of a severe allergic reaction.

Other options for testing include:

Food Challenge

Cytotoxicity Testing

Blood tests.

If You Suspect a Food Intolerance

Because a food intolerance is less severe, there is an effective way to self-diagnose referred to as an elimination diet. An elimination diet is performed over a period of 2-4 weeks. During this time, you will eliminate any foods that you suspect you have an intolerance to. For some people, this may be many food items leaving very few “safe” foods to start. The first phase in the process lasts about 2 weeks, then the suspected food items can start to be reintroduced one at a time for 2-3 days at a time. This second phase of introducing foods is where you pay close attention to any reactions or symptoms you experience with the reintroduction of food. Any adverse reaction may confirm that this is a food you are intolerant to and you should avoid this food moving forward.

Where to Find Help and Support

After seeing a Doctor or an Allergy Specialist, a Registered Dietitian is a valuable resource for anyone who is experiencing a food allergy or food intolerance, especially if you are faced with avoiding multiple foods or ingredients as the need to eliminate many foods from your diet puts you at risk for nutritional deficiency. A Dietitian can help you navigate the process as well as assist you in creating a meal plan that provides you with all essential nutrients for a healthy life.


Food Allergy vs. Intolerance: What’s the Difference? Available at Accessed April 13, 2022.

Food Elimination Diet. Available at Accessed April 13, 2022

How to Do An Elimination Diet and Why. Available at Accessed April 13, 2022

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