Corn Allergy Overview

While it's not common, people can be allergic to corn. The food allergy can cause symptoms like itching, a stuffy nose, and wheezing. Some people with a corn allergy have a serious reaction called anaphylaxis.

It's easy to tell if some foods have corn in them, like cornstarch or popcorn. However, corn can also be hidden in many other foods and products.

Foods made in a certain way also tend to have corn in them, such as food that's been changed to make it last longer or taste better (processed). About 75% of processed foods list corn as an ingredient.

It's important to know if your symptoms are from an allergy. Once you know for sure, you can take steps to stay safe.

This article will explain the symptoms of a corn allergy, how it's treated, and what you can do to prevent a reaction.

How Common Is a Corn Allergy?

We don't know how many people have a corn allergy. There has not been a lot of research on it. Here are two studies that looked at how common corn allergies are:

• A 2016 study in Pakistan used a food challenge test to see how many people had a corn allergy. In this test, a provider has a person eat a little bit of the food that might be causing allergy symptoms. Throughout the test, the person will eat more of the food and the provider watches to see if the person has an allergic reaction. The study in Pakistan that used this type of test found that about 1% of the population is allergic to corn.
• A study in Honduras tested 50 adults for a corn allergy. About 6% of them were found to be allergic to corn.

Having a corn allergy might not be common. It's also possible that more people are allergic to corn and don't know it. They may not realize that corn is causing their symptoms.

Signs and Symptoms

Food allergies can have a range of symptoms. You may have many of them or just a few. Corn allergy symptoms can include:

• Hives
• Itching in/near the mouth (oral allergy syndrome) and other parts of the body
• Flushing or reddening of the skin
• Hay fever-like symptoms (sneezing, nasal congestion, and runny nose)
• Wheezing and asthma symptoms
• Headaches
• Abdominal pain
• Nausea and/or vomiting
• Diarrhea

Sometimes, an allergy can cause a serious reaction. A person who is very allergic to corn can have anaphylaxis. The signs and symptoms of an anaphylactic reaction include:

• Swelling and/or tightness of the lips, tongue, throat, neck, or face
• Trouble breathing
• Hoarse voice
• Lightheadedness
• Fast heart rate
• Lethargy, confusion, or loss of consciousness
• Feeling very uneasy (a sense of "impending doom")

Causes

We know what causes some food allergies, like nuts, shellfish, and wheat. We're not sure why people are allergic to corn. Genetics, environment, and the way that genetics and the environment interact (epigenetic factors) probably play a role in corn allergies.

A protein in corn called zein could be what causes an allergic reaction. When zein gets into the body, the immune system might see it as an invader that needs to be fought. The body releases antibodies called immunoglobulin E (IgE) as a defense.

IgE tells the cells in the immune system to put out substances called histamines. It's the histamines that cause allergy symptoms.

Triggers: Foods and Products

Allergic reactions can happen from eating raw or cooked corn. It can also happen if you eat foods that were made using corn products.

Not all corn products contain zein, but it can be hard to know which ones do. Food labeling rules do not have "corn-free" as a designation.

Some items that are not food can also cause a reaction if you're allergic to corn. For example, medical products like surgical gloves and intravenous (IV) fluids are often made with corn products.

Other Allergies

People with a corn allergy can also get symptoms from corn pollen, grass pollen, and cornstarch. These allergens can cause symptoms of hay fever (allergic rhinitis) and/or asthma.

If you have asthma, eczema, hives, hay fever, or other food allergies, you might be more likely to be allergic to corn. Having someone in your family with a corn allergy, especially a sibling, also makes you more likely to be allergic to it.

Diagnosis and Testing

If you have an allergy, your health and safety depend on you knowing how to avoid what you're allergic to. However, diagnosing food allergies can be tricky.

Allergy testing with blood tests and skin tests does not always give results that are right. These tests often say that a person is allergic to something when they really aren't. This is called a false-positive test result.

The first step in figuring out if you have a corn allergy is talking to your doctor about your symptoms. For example, you might notice that you always get the same symptoms after you eat corn or any food that has corn in it.

Food allergies can be hard to spot, but a corn allergy can be tricky because:

• Corn is found in many foods and in varying amounts.
• The signs and symptoms of a corn allergy can also be caused by a lot of other allergies and health conditions. You might not even realize that your symptoms are related to corn. For example, you might just think you have a rash from a new body care product you've been using or that your stuffy nose is from a cold.

It can be helpful to keep a food diary. In it, you write all the foods that you eat, as well as when you ate them and whether you had any symptoms after.

Sometimes, cutting any foods that have corn in them from your diet can help you figure out if it was causing your symptoms. This is called an elimination diet. Once you stop eating foods with corn in them, you slowly start putting them back in. If you notice that you start having symptoms only after you start eating corn again, it can be a sign that you're reacting to it.

You might need to do a food challenge test. Instead of avoiding corn, you will eat it on purpose. However, you'll do this with a doctor present to make sure that if you have a reaction, someone is there to help you.

Treatment

If you only get mild allergy symptoms after eating corn, you may not need to do anything to treat it. You may find that taking an over-the-counter (OTC) medication to ease your symptoms is enough until the reaction passes.

The main way to treat a corn allergy is to prevent a reaction in the first place. That means doing your best to avoid corn and corn products.

If you have a serious allergy, you will need to be prepared. Epinephrine (EpiPen) is the only way to treat an anaphylactic reaction. You will need to carry one with you and know how to use it.

Anaphylaxis is a medical emergency, so you'll need to go to the emergency room or call 911 if it happens.

Prevention

The best way to prevent an allergic reaction is to avoid what you're allergic to. However, that's not always easy to do. There are many hidden sources of corn in foods and other products. These items also don't have to be labeled to let you know that they have corn in them. That means it's easy to be exposed to corn by accident.

Even if you know what to look for, you won't always have the option. For example, you may not have an ingredients list to look at when you're eating at someone else's home or at a restaurant.

When you're dining out, don't be afraid to talk to the person preparing your meal. You can ask them about the ingredients and how they are making the food. For example, if a dish is made without corn but made with corn oil, it could still trigger a reaction.

Children who are allergic to corn may have a harder time avoiding it. If you're a caregiver for a child with a corn allergy, you'll need to make sure that the school knows and that they can take steps to keep your child safe. You'll also need to talk to the caregivers of your child's friends before birthday parties and playdates.

Following a Corn-free Diet and Lifestyle

If you have a corn allergy, there are foods and ingredients that you should not eat. There are also some corn-based ingredients that are OK for some people with a corn allergy. You will need to talk to your doctor about whether you can safely have them in your diet.

Foods That Always or Often Contain Corn

• Corn syrup and high-fructose corn syrup (HFCS)
• Corn oil and vegetable oil
• Cornmeal
• Cornstarch
• Maize
• Popcorn
• Grits
• Hominy
• Corn sugars (including dextrose, dextrin, maltodextrin, fructose, Dyno, Cerelose, Puretose, Sweetose, glucose, sorbitol, xylitol, inositol, sodium erythorbate)
• Margarine
• Corn chips and tortilla chips
• Corn fritters
• Some breakfast cereal (such as corn flakes)
• Corn tortillas

Foods That May Contain Corn Products

Here are a few examples of foods that often have corn products like cornstarch, corn syrup, and corn/vegetable oils in them.

• Vegetable commercial soups and chili
• Peanut butter
• Meats including cold cuts like bologna, ham, hot dogs, sausages, and bacon
• Breaded or fried foods
• Cheese and cheese spreads
• Chop suey and chow mein
• Fish sticks
• Fried potatoes or fried rice (if corn oil is used)
• Frozen mixed vegetables
• Canned or creamed vegetables
• Succotash
• Pork and beans
• Bread dusted with cornmeal
• Graham crackers
• Baking mixes, pancake mixes, and pancake syrups
• English muffins
• Tacos and tamales
• Polenta
• Gravies that have been thickened with cornstarch
• Salad dressings and sauces
• Canned or frozen fruits sweetened with corn syrup
• Dates and other fruit confections
• Ice creams and sherbets
• Chocolate milk, milkshakes, soy milk, eggnog, and yogurt
• American wines, whiskey, gin, beer, and ale
• Carbonated beverages (including soda like Coca-Cola and 7-Up)
• Lemonade mixes
• Instant coffees
• Jams and jellies
• Candies and chewing gums
• Marshmallows
• Ketchup and mustard (prepared)
• White distilled vinegar
• Monosodium glutamate
• Baking powder, powdered sugar, cake yeast, and bleached flour
• Gelatin capsules
• Vanilla extract
• Malt syrup, modified food starch, caramel, cellulose, and xantham gum

Non-Food Items That May Contain Corn

There are also many items that are made with or using corn. Even though you don't eat these things, they might trigger a reaction if you're around them.

• Adhesives on envelopes, stickers, and stamps
• Paper containers like boxes, cups, plates, and milk cartons
• Food wrappers with cornstarch coatings
• Straws
• Toothpaste
• Laundry starch
• Medical products like surgical gloves coated with cornstarch and dextrose intravenous (IV) solution
• Pet Food
• Some clothing and fabrics
• Crayons
• Dishwasher soap
• Shampoo
• Paint

Summary

A corn allergy is a type of food allergy. It's not very common to be allergic to corn, but it can be serious. If you have symptoms after eating corn or using products made with corn, talk to your doctor.

Many products, even non-food items, have corn in them or are made using corn. If you have a corn allergy, it can be hard to avoid them. That said, your healthcare team can help you find ways to avoid corn and prevent an allergic reaction.

A Word From Verywell

Finding out you're allergic to corn can be frustrating because so many foods and other products are made with it. Avoiding corn as much as you can is the best way to prevent allergy symptoms.

If you're adjusting to a corn-free diet, start with foods like eggs, meat that is fresh and does not have chemical preservatives (unprocessed), oats, wheat, quinoa, beans, and rice. You might even be able to find corn-free versions of your favorite food and non-food products at health food stores.

Living with any allergy means having a lot to learn. Luckily, there are many resources to help. For example, the Food Allergy Research and Education organization offers tips for living with a food allergy. It also provides information on how to prepare for and manage severe reactions.