Though not considered a common food allergen in the U.S., corn allergy is increasingly being discussed in doctors’ offices across the country. There is no agreement yet on the number of people in the U.S. with corn allergy.
One study reported 2 percent of nearly 4,500 respondents self-reported they were allergic to corn. Corn allergy can be difficult to diagnose using standard skin or blood tests due to cross reactivity between corn and grass pollens, and other seeds and grain.
Whatever the number, allergic reactions to corn can be very serious. There are published case reports that have reported life-threatening anaphylactic reactions to corn, including reactions to cornstarch used in surgical glove powder.
The U.S. is the world’s largest producer of corn, also known as maize, which is the nation’s top crop. Individuals avoiding corn should avoid both raw and cooked forms of corn.
Corn is found in a wide variety of packaged foods, such as:
- Snack foods
- Canned fruits
- Prepared meats like hot dogs and deli meats
Read all ingredient labels carefully to determine if a product contains corn or ingredients made from corn, and contact the manufacturer with any questions.
Ingredients to avoid include
- Corn syrup
- Corn flour
- Corn/vegetable oil
As with other foods, the symptoms of a corn allergy may include:
- Hives or skin rash
- Nausea, stomach cramps, indigestion, vomiting, diarrhea
- Stuffy/runny nose
Symptoms may range from mild to severe. A severe life-threatening allergic reaction is known as anaphylaxis, which is rapid in onset and may cause death.
Treatment for corn allergy includes strict avoidance of corn ingredients. An allergist may prescribe medications such as epinephrine (adrenaline), available in an auto-injector, and other medications, such as an antihistamine, to treat symptoms of an allergic reaction. It is important to note that while antihistamines may help relieve some allergic symptoms, it is not a substitute for epinephrine, which is the first-line treatment for anaphylaxis.
If you suspect you are allergic to corn, make an appointment to see an allergist who specializes in food allergy. Keep a food diary before the appointment, and make note of any reactions. If you have a reaction, you should note the:
- Time symptoms started
- Foods eaten
- Treatment that was administered
- Length of time that passed before symptoms ended
Corn allergy should be confirmed by an oral food challenge, administered by an allergist in a clinical setting, before an elimination diet is followed. If a corn allergy is diagnosed, you should receive a prescription for epinephrine, the first-line treatment for anaphylaxis. Epinephrine is available in an auto-injector, and patients prescribed epinephrine should have it available at all times. Your allergist will show you how to properly use your epinephrine auto-injector.