Food allergies can begin at any age

Suspect you have food allergies?

> Make an appointment with an allergist

You’ve always been able to eat a certain food, such as shrimp or strawberries, but suddenly you have a reaction to it. Do you have a food allergy?


Understanding the causes and signs of food allergies can help you discover what’s going on and develop a plan to combat them.

How food allergies develop

“An allergic reaction is a person’s body detecting something foreign,” said Charles Frey, Jr., DO, an allergist with OSF HealthCare. “The immune system says, ‘Hey, this shouldn’t be here,’ and causes functions to rid the body of what it considers foreign or ‘bad.’”

For example, a person allergic to ragweed pollen may sneeze, cough and have a runny nose. This is the body’s way of trying to flush out the pollen. With food allergies, the immune system tries to get rid of the allergen through vomiting and diarrhea, but they can also cause hives or more serious reactions.

“Exposure to an allergen is what causes an allergy. You can’t develop an allergy to something that you have never been exposed to,” Dr. Frey said.

The first time someone who is prone to allergies is exposed to a potential allergen, a strong immune response is not likely. When a person has been exposed to a food more than once, the body can develop allergic antibodies, which may prompt dramatic symptoms. Those include hives or rashes, swollen lips or tongue, or even anaphylaxis, which could include life-threatening breathing problems and low blood pressure.

How children and adults develop allergies

In children, the most common food allergies include milk, egg, peanuts and tree nuts (such as almonds and walnuts). For adults, the most common new food allergies include fish, shellfish, tree nuts and peanuts.

Why the difference?

A child’s diet determines what kinds of allergies could develop. For example, shellfish allergies in children are not very common, because children do not typically eat much shellfish. (That same principle is why sesame seed allergies are more common in some Asian countries, because diets there have more exposure to sesame.)

Children often outgrow some of these allergies. Approximately 70% of children with milk, wheat or egg allergies no longer have them as adults. Children are much less likely to outgrow nut allergies.

It’s less likely for an adult to outgrow a food allergy. That’s because the types of allergies that adults develop — such as tree nuts and shellfish — are less common for children to outgrow.

Diagnosing and managing food allergies

Food allergies can quickly become life-threatening. So, if you have a food allergy or even suspect one, your first step should be to see an allergist.

An allergist can do skin or blood tests to confirm a food allergy. A person can be re-tested periodically to see if the allergy remains.

woman turning away food

The first and best course of action for managing food allergies is to avoid the food.

But even taking those precautions, you should be prepared for accidental exposure. This preparation includes having an epinephrine auto-injector pen, such as the EpiPen – and knowing how to use it.

Because anaphylaxis as an allergic response can become life-threatening in a very short time, an EpiPen can be a lifesaver.

Preventing and treating food allergies

Cause and prevention of food allergies is an emerging field of research, so recommendations have changed over the years.

Just a few years ago, parents of young children were cautioned not to give children peanut butter before the age of 2. But researchers have found that exposure to small amounts very early in life, between 6 months and 2 years old, may lead to fewer peanut allergies.

Researchers are also looking for ways to help people with severe allergies develop immunity through careful, well-monitored exposure to allergenic substances.

If you have food allergies, consider regular check-ups with your allergist to learn of new treatments and therapies.

Last Updated: January 19, 2022

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About Author: Nancy Piccione

Nancy Piccione has worked as a journalist, public relations professional, and homeschooling mom. She has a B.A. in English from Kenyon College and a master’s degree from Northwestern University’s Medill School of Journalism.

She and her husband, Joseph, have called Central Illinois “home” for the past 25 years. They have three young adult children. She is a lover of book clubs, hiking, board games, and travel.

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Categories: Diet & Exercise