The 8 most common food allergies

About 32 million Americans have food allergies and can experience potentially life-threatening allergic reactions.

Most of these reactions are mild or moderate, but some food allergies can be life-threatening. Unfortunately, there's no cure for food allergies. In most cases, you must avoid foods you're allergic to in order to prevent having a reaction.

Your body's immune system keeps you healthy by fighting off things that can harm you, such as infections. In a food allergy, your immune system identifies protein in a certain food as a danger and reacts to protect you. This allergic reaction can cause bothersome or even dangerous symptoms that can affect your eyes, nose, throat, respiratory system, skin and digestive system. Most people need to eat the food to have an allergic reaction. However, some people are highly sensitive to the food they're allergic to and can have a reaction from breathing in the allergen or having it touch their skin.

Food allergy symptoms usually show up a few minutes to two hours after you eat a food you're allergic to. But in some cases, symptoms may not start for several hours after you've eaten the food. Reactions can range from mild to severe and life-threatening, and they can get worse over time. This means if you had a mild reaction to a food in the past, future reactions could be more severe. Most food allergies start in childhood, but they can develop at any age. Allergic reactions to foods can happen even if you've consumed the food before without symptoms. For instance, you may have been able to eat shrimp without a problem years ago, but eating it now may give you hives.

Symptoms of food allergies vary, too. They can affect different parts of your body at the same time. If you have any severe symptoms, seek medical help right away. Signs of an allergic reaction to a food can include:

• Hives or a rash
• Pale, flushed or blue-colored skin
• Vomiting, stomach cramps or diarrhea
• Repetitive cough
• Stuffy, itchy or runny nose or sneezing
• Itchy or watery eyes
• Tight or itchy feeling in your mouth
• Trouble swallowing
• Face, tongue, throat or lip swelling, which could cause trouble talking
• Shortness of breath, wheezing or trouble breathing
• Dizziness
• Weak pulse
• Loss of consciousness
• Anaphylaxis. This life-threatening reaction sends your body into shock. It can cause trouble breathing, a sudden drop in blood pressure and other symptoms. Call 911 right away if you have signs of anaphylaxis.

Symptoms of a food allergy can vary from person to person. Also, someone with a food allergy may not experience the same type and severity of symptoms during every reaction. Sometimes after symptoms go away, they may reappear an hour or more later. The second wave of symptoms is called a biphasic reaction.

It's possible to outgrow a food allergy, especially if the allergy started during childhood. Often a milk, egg, wheat and soy allergy starts in childhood but may be outgrown later. However, peanut, tree nut, fish and shellfish allergies are more likely to last a lifetime.

More than 170 foods have been reported to cause allergies. While people can have everything from an MSG allergy to a strawberry allergy, nine in every 10 allergic reactions to foods involve one of the following eight food allergies:

• Milk allergy
• Eggs allergy
• Wheat allergy
• Peanut allergy
• Tree nut allergies, such as almonds, pecans and walnuts
• Fish allergies, including bass, cod and flounder
• Shellfish allergies, like lobster, shrimp and crab
• Soybean allergy

Under the Food Allergen Labeling and Consumer Protection Act of 2004, food manufacturers are required to identify these eight foods, or any ingredient that's derived from these foods, on ingredient labels. (Note that this Act doesn't apply to the labeling of poultry, most meats, some egg products and most alcoholic beverages.) This can help you easily spot products that contain foods you're allergic to so you can avoid them. These foods can be listed in parenthesis following the ingredient that contains them, such as flour (wheat). Or they can be included after or next to the ingredient list in a "contains" statement, like "contains tree nuts, milk and soy."

Keep in mind that you can be allergic to other foods besides the eight most common ones. The law only requires that common food allergens be called out on food labels. If you're allergic to an uncommon food, you must read ingredient lists very carefully.

A wheat allergy is not a gluten allergy. In fact, gluten allergy is an incorrect term. It's often misused to describe a sensitivity to gluten. It's also different from celiac disease. This is an autoimmune disorder where the intestinal lining can't absorb and is harmed by foods that contain gluten.

See your healthcare provider if you think you have a food allergy. They will likely ask you about your medical history, suggest that you keep a food diary and possibly do testing. Testing for food allergies may involve skin testing and/or blood tests. You may need to see an allergist to be tested for food allergies.

If you're diagnosed with a food allergy, you will likely need to learn how to avoid foods you're allergic to. This involves reading food labels closely and carefully preparing foods at home. You'll also need to use caution when dining out, which includes alerting restaurant staff about your allergy and asking if they can prevent cross-contamination of ingredients (this happens when a small amount of a food allergen accidentally gets into another food). You'll also need to learn how to spot the signs of an allergic reaction and know what actions to take if you have one. Adapting to life with a food allergy can be nerve-wracking and overwhelming at first, but many people say that avoiding trigger foods becomes second nature in time.

Updated February 2021.