What is a food allergy?
A food allergy is when your body’s immune system reacts to a food protein because it has mistaken that food protein as a threat. Symptoms can range from mild to life-threatening.
What is the difference between food allergy and food intolerance?
Food allergy is sometimes confused with food intolerance. Food allergies involve your immune system and can be life-threatening. An intolerance is when your body has trouble digesting a food. It can make you feel badly, usually with an upset stomach, but it is not life-threatening. The most common intolerance is to lactose—which is a natural sugar found in milk.
What are the most common food allergens?
More than 170 foods are known to cause food allergies, but eight foods account for 9 out of 10 reactions in the United States. They are milk, eggs, peanuts, tree nuts, soy, wheat, fish and shellfish.
What are the symptoms of a food allergy reaction?
An allergic reaction to food can have many different symptoms, and a single person can experience different symptoms from one reaction to the next. Many reactions start with skin symptoms, like hives or a rash, but some do not. More serious symptoms like a drop in blood pressure and trouble breathing can be life-threatening. Talk to your allergist and work with them to fill out a Food Allergy & Anaphylaxis Emergency Care Plan to be prepared in an emergency. A complete list of symptoms of a food allergy reaction is available at foodallergy.org/symptoms.
What is anaphylaxis?
Anaphylaxis is a serious allergic reaction that comes on quickly and may cause death. Early use of an epinephrine auto-injector is the primary treatment for anaphylaxis. A complete list of the symptoms of anaphylaxis and more information are available at foodallergy.org/anaphylaxis.
Will antihistamines stop anaphylaxis?
No. While antihistamines can help relieve some mild symptoms from an allergic reaction, such as an itchy mouth or hives, they cannot stop the life-threatening symptoms of anaphylaxis.
How much of a food allergen does it take to cause a reaction?
Even trace amounts of a food allergen can cause a reaction in some people with food allergies. Although ingestion is the primary cause of severe reactions, in some cases, skin contact or breathing in a food protein (e.g., steam from cooking shellfish) can cause symptoms.
How long does it take for a reaction to start after eating a food?
Symptoms usually start as soon as a few minutes after eating a food and as long as two hours after. In some cases, after the first symptoms go away, a second wave of symptoms comes back one to four hours later (or sometimes even longer). This second wave is called a biphasic reaction. The risk of a biphasic reaction is why patients who have a severe reaction should stay at a hospital for four to six hours for observation.
Who is most at risk for a severe allergic reaction to food?
Anyone who has a food allergy can have a severe allergic reaction to food. However, having asthma puts you at higher risk. Fatal outcomes of anaphylaxis include a disproportionate number of teens and young adults, possibly because they take more risks with their food allergies (eating dangerously and delaying treatment).
Can the severity of a person’s allergic reactions to food be predicted from his or her previous reactions?
No. Someone whose reactions have been mild in the past may suddenly experience severe reactions that could be deadly.
How many people have food allergies?
As many as 15 million Americans have food allergies, including nearly 6 million children.
Why are food allergies increasing?
The Centers for Disease Control and Prevention have reported a 50 percent increase in the number of children with food allergies since the late 1990s. Many theories have been suggested as to why the number of people with food allergies is growing, but scientific research has not yet found the cause.
Is there a cure for food allergy?
Not yet. Strict avoidance of the food allergen is the only way to prevent a reaction and an epinephrine auto-injector is the only medicine to stop a severe reaction called anaphylaxis.
Can a person outgrow their food allergies?
Peanut, tree nut, fish and shellfish allergies usually are lifelong. Milk, egg, wheat and soy allergies usually begin in childhood and eventually may be outgrown.
If I think I or my child has outgrown an allergy to a food, is it okay to try a small amount of that food?
No. Only your allergist can test for this. For more information on tests for food allergies, visit foodallergy.org/diagnosis.
What to Read Next
Learn about the mild and severe symptoms of a food allergy reaction—and what to do next.
Get to know this document, the cornerstone of personalized treatment for any person with a food allergy.