What is the most common food allergy?
Short answer
Allergy question
There is no single answer for every age group. Shellfish is the most common food allergy among US adults, while milk is the most common in young children. Overall, shellfish, milk, peanut, tree nuts, and egg are the leading food allergies in the United States.
This is a general research summary, not a diagnosis. A clinician or a test can confirm what applies to you.
Key facts
Milk is the most common food allergy in infants and young children, affecting about 2.5 percent of children under age 3.
About 60 percent of people with a shellfish allergy experience their first allergic reaction as adults, making it the leading food allergy in adults.
Almost 6 percent of US adults and children have a food allergy.
Here's the nuance
A one-liner rarely tells the whole story. This is the honest detail behind the short answer above.
The most common food allergy depends on which age group you are asking about. Counting the entire US population, shellfish is the single most common food allergy, affecting roughly 2 to 3 percent of adults. Shellfish allergy usually first appears in adulthood, is rarely outgrown, and affects a very large group of people. In infants and young children, milk is the most common food allergy, followed closely by egg and peanut.
The pattern shifts with age. Children most often react to milk, egg, and peanut. Many outgrow milk and egg allergies by school age, but peanut allergy usually persists for life. In adults, the leading food allergies are shellfish, tree nuts, peanut, and fish. About 6 percent of US adults and children have a food allergy, according to CDC data.
Nine foods, sometimes called the Big 9 major allergens, cause the large majority of serious reactions: milk, egg, peanut, tree nuts, wheat, soy, fish, shellfish, and sesame. Sesame became the ninth federally recognized major allergen on January 1, 2023, under the FASTER Act. Together these nine foods account for roughly 90 percent of allergic reactions, although nearly any food can trigger one.
It is important to separate a true food allergy, which involves the immune system, from a food intolerance. Lactose intolerance, for example, is a digestive problem and is not the same as a milk allergy. A true allergy can cause anaphylaxis, a severe, rapid, whole-body reaction that requires epinephrine and a call to 911. Antihistamines do not treat anaphylaxis. If you suspect a food allergy, see a board-certified allergist for testing rather than self-diagnosing.
The key points
The handful of things that decide the answer — skim these if you only read one section.
Shellfish leads in adults
Shellfish is the most common food allergy among US adults, affecting about 2 to 3 percent. It typically begins in adulthood and is rarely outgrown.
Milk leads in young children
Milk is the most common food allergy in infants and young children, followed by egg and peanut. Many children outgrow milk and egg allergies.
The Big 9 cause most reactions
Milk, egg, peanut, tree nuts, wheat, soy, fish, shellfish, and sesame account for roughly 90 percent of allergic reactions in the US.
Sesame is the newest major allergen
Sesame became the ninth federally recognized major food allergen on January 1, 2023, under the FASTER Act, and must now be labeled on packaged foods.
Allergy is not the same as intolerance
A food allergy is an immune reaction that can cause anaphylaxis, while an intolerance such as lactose intolerance is a digestive issue and is not life threatening.
A note on how to use this
Informational only — not a diagnosis
This page is a general research summary about allergies and allergy care. It cannot tell you whether you personally have an allergy or what is triggering your symptoms. It is informational only and never a substitute for evaluation by a licensed clinician.
If you want a real answer for your body, at-home allergy testing or a visit with a clinician can identify what you actually react to — this page cannot diagnose you.
❓Frequently Asked Questions
Milk is the most common food allergy in infants and young children, followed by egg and peanut. Many children outgrow milk and egg allergies by school age, but peanut allergy usually lasts into adulthood. A board-certified allergist can confirm a diagnosis and track whether a child is outgrowing an allergy.
Shellfish is the most common food allergy in US adults, followed by tree nuts, peanut, and fish. Shellfish allergy often begins in adulthood, and about 60 percent of people with it experience their first reaction as adults. Unlike milk and egg allergies, shellfish allergy is rarely outgrown.
The nine major food allergens recognized in the US are milk, egg, peanut, tree nuts, wheat, soy, fish, shellfish, and sesame. Sesame was added on January 1, 2023, under the FASTER Act. These nine foods must be clearly labeled on packaged products and cause about 90 percent of reactions.
No. A food allergy involves the immune system and can cause anaphylaxis, a rapid and dangerous reaction. A food intolerance, such as lactose intolerance, is a digestive problem that causes discomfort but is not life threatening. If you have severe or fast-onset symptoms, see an allergist for proper testing.
Reviewed by
Curex Editorial TeamReviewed for accuracy
Last reviewed August 2026
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