Corn Allergy: Symptoms and Diagnosis

Allergies occur when your immune system reacts abnormally to allergens or substances that are harmless to most people. So if you have a corn allergy, then your body will react to corn proteins by releasing antibodies to fight them. The best way to prevent a reaction is to avoid all products with corn, cornstarch, or corn-based sweeteners; however, this allergy is not always caused by food. Corn can be inhaled in hair sprays and perfumes and is even found in toothpaste! Corn allergies are becoming more common, but are not nearly as well known as soy, wheat, milk, tree nut, shellfish, fish, and egg allergies.

Depending on how severe your allergy is, you could suffer symptoms ranging from less serious symptoms to life-threatening symptoms.

Less Serious Symptoms

  • Itching or tingling sensation in the mouth
  • Hives, skin rash, or eczema
  • Swollen lips, face, tongue, and/or throat
  • Difficulty breathing or wheezing
  • Drop in blood pressure
  • Congestion
  • Diarrhea
  • Sneezing
  • Asthma
  • Abdominal pain, headaches
  • Arthritis
  • Fluid retention
  • Urticaria
  • Fibromyalgia
  • Fatigue
  • Nausea
  • Vomiting
  • Lightheadedness, dizziness

Severe, Life-Threatening Symptoms

  • Rapid and irregular pulse
  • Anaphylactic shock – this is when a person goes into shock within minutes of exposure to the allergen, and if it isn’t treated immediately, it can be fatal. A visit to the emergency room and an injection of epinephrine is the treatment in this case.
  • Loss of consciousness
  • Extreme difficulty in breathing due to swelling of the throat and air passages

In cases of more serious reactions, you should contact your emergency service immediately. You should wear a medical bracelet at all times if you suffer from a life-threatening allergy. If you have a severe allergy, you will need to carry an injection of epinephrine with you at all times.


It is difficult to diagnose a maize allergy, and if you suspect you are allergic to maize, you should arrange to see an allergist who will set up tests as confirmation of the allergy. In the meantime, you could note the duration of your symptoms and what food you ate at the time, which will help the allergist to make a quicker diagnosis. Your allergist will probably use a skin or blood test to confirm your allergy. The skin test is done by placing a small amount of the allergen on an adhesive patch and placing it on scratched skin to see if there is a reaction. A blood test will check your immunoglobulin E levels to confirm the diagnosis. If the results are positive, depending on the severity of your allergy, you will probably be treated with an epinephrine auto-injector or another type of antihistamine.

Coping with the Allergy

Cutting out maize completely from your diet will of course stop any symptoms, but it will also alter your diet extensively. Although this is a relatively rare allergy, if you do find that you are allergic to this food item, you will probably find it difficult to eradicate it from your diet. And you will have to avoid this cereal crop in both its raw and cooked forms. Being careful about what you eat is very important when you have a corn allergy. It might be beneficial to consult a clinical dietician to help you plan a diet that is completely free of maize but that will still provide you with essential vitamins and nutrients. It is one of the most difficult allergies to deal with, as maize is a common ingredient in food and cosmetics.

Eating cleaner, non-processed foods is advisable as you know exactly what you’re eating. Fast foods and industrial foods should be avoided, as maize can be found in small or large amounts in almost all of these foods.

Corn is hidden in a wide range of products; for instance, many types of starch contain it. Even some shampoos and skin lotions have maize derivatives in them. And the ingredient labels on food might not mention that some foods, like citric acid, are made with this cereal crop.

Some more unusual food items or food processes that can contain corn or its derivatives include:

  • Tea bags – the gum used to seal the bags contains corn
  • The process of vacuum packing food products includes the use of cornstarch
  • Binders in vitamins and supplements are corn by-products
  • Sweeteners in chewing gum
  • Canned fruits
  • Bath oils, body lotions, shampoos, and toothpastes
  • Cleaning products
  • Medicines and ointments
  • Glue on envelopes and stickers
  • Vanilla extract
  • Vitamins used to fortify milk
  • Enzymes used to ferment cheese
  • Fabric softeners and toilet paper

Fumes from maize products can be inhaled and produce allergic reactions, for example, hairsprays, perfumes, and vegetable oil sprays.

When you have the allergy, it’s imperative to check food labels to see if any corn or its derivatives are present in the food item. However, the problem with food labels is that many do not list all derivatives, so you need to be careful.

Common corn-containing foods are:

  • Cereals
  • Jams
  • Syrups
  • Snack foods
  • Beverages and sodas
  • Beers, whiskeys, and other alcoholic drinks
  • Candies
  • Luncheon meats
  • Sauces and marinades
  • Baking powder
  • Cornstarch
  • Pastries
  • Fresh corn
  • Canned sweet corn
  • Popcorn and caramel corn
  • Infant formulas
  • Polenta

Other ingredients to avoid include:

  • Caramel
  • Dextrose
  • Dextrin
  • Fructose
  • Malt syrup
  • Modified starch and vinegar
  • Corn syrup
  • Cornstarch
  • Corn/vegetable oil

A corn allergy is one of the most frustrating allergies to have, and you have to be prepared to change your lifestyle a lot. Going to parties or other gatherings can become complicated as you should take your own food with you if you hope to avoid all corn. You may also need to take your own drinks if you have a severe allergy. Even holidays could be different, with more eating at home than out at restaurants. Unfortunately, a food allergy is not like a diet – you won’t be able to cheat, or you will pay penalties. You will have to plan more than ever and probably spend a lot of time preparing foods in advance.

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