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Diagnosing Food Allergies

Learn the process of diagnosis and treatment of a food allergy.

Diagnosing Food Allergies

Many folks view this whole food-sensitivity business as faddism and quackery, and unfortunately, we have earned this mindset. Did you know that out of the gazillions of people who think they have a food allergy, less than 2 percent of the American adult population actually have one? Why does the idea of a food allergy get so recklessly thrown around? One reason may be that people are often quick to blame physical ailments on food. Another aggravating reason for all the misdiagnoses are those so-called “allergy quacks” that grab your hard-earned money and diagnose you with the “allergy of the month.”

In today’s world, a true food allergy can be properly diagnosed with scientific sound testing. If you think you might suffer from an allergic response to certain foods, get it checked out. The first step is to find a qualified and reputable physician who has been certified by the American Board of Allergy and Immunology. Ask your primary doctor for a referral, or call the American Academy of Allergy and Immunology at 1-800-822-2762, and it’ll set you up with a physician in your area. Next, schedule an appointment. Here’s what you can expect:

Food for Thought

For further information and a free newsletter on food allergies, send a self-addressed stamped envelope to:

The Food Allergy and
Anaphylaxis Network (FAAN)
10400 Eaton Place, Suite 107
Fairfax, VA 22030

  • Thorough medical history. You’ll give a detailed history of both your and your family’s medical background. Special attention will be given to the type and frequency of your symptoms, along with when the symptoms occur in relation to eating food.
  • Complete physical examination. You’ll have a routine physical exam, with special focus on the areas where you experience the suspected food-allergy symptoms.
  • Food-elimination diets. The doctor will probably have you keep a food diary while you eliminate all suspicious foods from your diet. The allergist might then tell you to slowly, one at a time, add these foods back to your diet so you can specifically identify which foods might cause an adverse reaction.
  • Skin tests. An extract of a particular food is placed on the skin (usually on the arm or back) and then pricked or scratched into the skin to look for a reaction of itching or swelling. This isn’t 100 percent reliable because people who aren’t allergic can develop skin rashes. On the other hand, some people don’t show skin reactions but do have allergic responses when they eat the food.
  • RAST (radioallergosorbent test). This test involves mixing small samples of your blood with food extracts in a test tube. If you are truly allergic to a particular food, your blood will produce antibodies to fight off the food extract. One advantage is that this test is performed outside your body, so you don’t have to deal with the itching and swelling if the test is positive. Note: this test will only foretell an allergy, not the extent of sensitivity to the offending food.
  • Double-blind food-challenge tests. This type of test must be performed under close supervision, preferably in an allergist’s office or hospital, and it is considered the “gold standard” in food-allergy testing. Two capsules of dried food are prepared, one with the real McCoy and another with a nonreactive substance. Neither doctor nor patient knows which is which (a double-blind challenge). These challenges can rule out, as well as detect, allergies or intolerances to foods and other food substances such as additives.

Treating a True Food Allergy

What’s the treatment once you’re diagnosed with a true food allergy? Avoid the offending food!

Although this list is not a substitute for consulting a registered dietitian, it can provide a pretty good idea of which food ingredients to avoid after you’ve been diagnosed with one of the following food allergies:


Some people are diagnosed with allergies to food additives such as sulfites (food preservatives), tartrazine (food colorings), and MSG (flavor enhancer) and therefore must check ingredient labels with extreme care and ask a lot of questions when dining out.

  • Cow’s milk. Check labels carefully and avoid all foods with the following ingredients: milk, yogurt, cheese, cottage cheese, custard, casein, whey, ghee, milk solids, curds, sodium caseinate, lactoglobulin, lactalbumin, milk chocolate, buttermilk, cream, sour cream, and butter.
  • Wheat. Avoid all foods with the following ingredients: wheat, wheat germ, all-purpose flour, duram flour, cracker meal, couscous, bulgur, whole-wheat berries, cake flour, gluten flour, pastry flour, graham flour, semolina, bran, cereal or malt extract, modified food starch, farina, and graham.
  • Corn. Avoid all foods with the follow-check ingredient labels with the following ingredients: fresh, canned, or frozen extreme care and ask a lot of corn (regular and creamed), hominy, corn grits, maize, cornmeal, corn flour, corn sugar, baking powder, corn syrup, cornstarch, modified food starch, dextrin, malto-dextrins, dextrose, fructose, lactic acid, corn alcohol, vegetable gums, sorbitol, vinegar, and popcorn.
  • Soy. Avoid all foods with the following ingredients: soy, lecithin, tofu, textured vegetable protein (TVP), tempeh, modified food starch, soy miso, soy sauce, teriyaki sauce, and soybean flour.
  • Nuts. Folks who are allergic to peanuts and other types of nuts not only have to avoid the obvious plain nuts and nut butters, but also need to be on the lookout for “hidden” nuts tossed into baked goods, vegetarian dishes, candies, cereals, salads, and stir-fry meals.
  • Eggs. Avoid all foods that indicate the presence of an egg by listing any of the following ingredients: powdered or dry egg, egg white, dried egg yolk, egg substitute, eggnog, albumin, ovalbumin, ovomucin, ovomucoid, vitellin, ovovitellin, livetin, globulin, and ovoglobulin egg albumin.
  • Shellfish. Avoid all shrimp, lobster, prawn, crab, crawfish, crayfish, clams, oysters, scallops, snails, octopus, squid, mussels, and geoducks.

Some people have such severe food allergies that they can even exhibit symptoms from the following:

  • Kissing the lips of someone who has eaten the offending food
  • Just smelling and inhaling the offending food while it cooks
  • Coming into contact with utensils that have touched the offending food—make certain that food companies do not have cross-contamination from product to product

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