Do I Have a Food Allergy?

Food allergies are becoming more common among adults. Researchers estimate that over 10% of adults in the U.S. have a food allergy. And that might be an underestimate, given almost 20% of adults self-report a food allergy. What’s more, roughly half of these people with food allergies developed them as an adult.

If you have been diagnosed with a food allergy, or if you’re wondering if you have one, we’re here to answer some common questions. We explain what causes an allergic reaction to food, how to know if you have an allergy rather than sensitivity, and common foods associated with a true food allergy.

What causes food allergies? 

Food allergies occur when your immune system overreacts to a specific food. 

Immunoglobulins (Ig) are a type of protein in your body. Different types of immunoglobulins have different roles. Immunoglobulin E (IgE) recognizes anything foreign to your body that might be harmful — like a parasite, bacteria, or even a cancer cell. 

In a food allergy, IgE mistakenly labels a food as a harmful invader. When you eat that food, IgE signals your body to react. These signals cause the release of chemicals that lead to many of the symptoms of allergic reaction.

No one knows why some people make IgE against certain foods. But there are factors that make a person more likely to develop a food allergy. They include:

• History of other allergic conditions: This includes eczema, seasonal allergies, and asthma. 

• Age: A young child is more likely to develop a food allergy compared to an adult. But someone can develop an allergy at any point in their life.

• Family history: If you have an immediate family member with a food allergy, your risk of a food allergy is nearly two times more than the normal population. If you have two family members with a food allergy, that risk increases to almost double the normal population. 

Symptoms of a food allergy

Many people experience symptoms and reactions after eating certain foods. But that doesn’t mean you have a food allergy. 

Allergic reactions to food occur soon after you eat. Symptoms often begin within minutes, but sometimes they can take up to 1 hour. These symptoms include:

• Skin rash or itching: Hives are a common allergy symptom. They are itchy rashes that tend to start (and go away) much quicker than most rashes. But they can look different on different people. Sometimes they look like small bumps, other times they look like big welts. And other people will just experience itchy skin without an obvious rash. 

• Swollen tongue or lips: This can start with just an itching or tingling in your mouth. But it can progress to noticeable swelling, which is one of the more dangerous allergic reaction symptoms. It can get worse quickly and affect your ability to get air into your lungs. 

• Throat symptoms: These can include an itchy throat, a hoarse voice, trouble swallowing, or a feeling like swelling in the throat. 

• Difficulty breathing: Some people develop a sudden onset cough, wheezing, a tight feeling in their chest, or shortness of breath. 

• Stomach symptoms: This can be nausea, stomach cramping, or vomiting. And it can start almost as soon as you eat (unlike other stomachaches, which usually take a little time after eating). 

• Pale or blue skin: You may first notice this in the lips or fingertips. 

• Lightheadedness: This may occur as you try to stand up. In severe reactions, you can faint.

If you have any of these symptoms after eating, you may be experiencing anaphylaxis — a severe allergic reaction. Anaphylaxis is a serious, life-threatening allergic reaction. It needs immediate medical attention and can be fatal without prompt treatment.

How is food allergy different from food sensitivity or intolerance?

Food sensitivities and intolerances are different from food allergies. Although food allergies are very common, food intolerance is even more common. Food intolerance affects up to 20% of people. 

There are some important differences between a food allergy and food sensitivity. Unlike a food allergy, food sensitivities:

• Are not caused by the immune system

• Are not potentially fatal

• Typically only affect the skin or gastrointestinal tract

• Tend to take longer to develop, rather than within minutes of eating

In most cases, food sensitivities are also worse when you eat more. This isn’t true of food allergies, where even a tiny amount can cause a potentially fatal reaction.

Most common food allergies

The cause of most food allergies — up to 90% — come from the following 8 foods:

1. Milk/dairy (the most common)

2. Eggs

3. Peanuts

4. Tree nuts (like almonds, cashews, walnuts)

5. Fish

6. Shellfish

7. Wheat

8. Soy

The FDA requires that food labels list these top eight food allergens. Sometimes food allergens can have tricky names that make it hard to know if a food is safe for you to consume. For this reason, the FDA mandates that food labels clearly identify the allergen in parentheses or at the end of the label. 

Starting in January of 2023, the FDA will name sesame as a common food allergy. But until that time, food labels don’t have to list sesame as a potential allergen.

Can you outgrow a food allergy? 

Yes, although experts don’t fully understand why or how this happens. Allergies to certain foods, like milk and eggs, are more likely to improve as children get older. In fact, by the age of 16, about 70% of kids can outgrow a milk or egg allergy. But seafood and nut allergies are more likely to continue into adulthood. 

Although some allergies are more likely to be lifelong, there is hope. Researchers are working on potential treatments. Many of these methods allow people to build tolerance to their allergen. These treatments don’t fully get rid of the allergy. But they lower the risk of a life-threatening reaction when someone comes into contact with it. 

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Written by:

Jill L. Jaimes, MD

Jill L. Jaimes, MD, is a board-certified pediatric emergency medicine physician with over 20 years of clinical experience. She received her medical degree from Baylor College of Medicine and completed her residency and fellowship training at Texas Children’s Hospital.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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