Any time people eat, they come in contact with substances that could trigger allergic reactions. Although people can have these reactions due to many foods, just a handful of foods cause most allergies.

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Foods contain protein allergens. For the majority of people, these proteins do not trigger an allergic reaction. While many foods can cause an allergic reaction, only nine common foods cause 90% of allergies in the United States. These are:

  • milk
  • eggs
  • fish
  • shellfish
  • tree nuts like almonds or pecans
  • peanuts
  • wheat
  • soybeans
  • sesame

Children most commonly experience food allergies to peanuts, milk, soybean, tree nuts, eggs, and wheat, but many children stop being allergic to foods like milk, egg, wheat, and soy early in their childhood.

Adults with food allergies typically react to tree nuts, peanuts, fish, and shellfish. When a person thinks they have a food allergy but is not sure what food they are reacting to, an allergist can recommend a food allergy test. This can be done via either a skin or a blood test.

This article looks at the different types of common food allergies, the symptoms of each allergy, and what people can do to avoid a reaction. In severe cases, food allergies can lead to a serious and sometimes fatal allergic reaction called anaphylaxis. A person experiencing this severe reaction should seek medical attention immediately. Whenever possible people should keep epinephrine on hand and use it to treat anaphylaxis immediately.

Like many food allergies, an egg allergy is common in childhood. The major proteins that cause an allergic reaction to eggs are ovomucoid, ovalbumin, and ovotransferrin.

Some people can consume baked or cooked eggs without getting an allergic reaction, but not others. Some people might also get an allergic reaction to eggs if they are allergic to the bird that laid the egg or its feathers. This is called bird-egg syndrome.

Egg allergy symptoms

Symptoms of an egg allergy can include vomiting, stomach pain, indigestion, wheezing, or cough. The best way to avoid an allergic reaction to eggs is to avoid eating eggs or food products that contain them.

An allergy to eggs is not the same as egg intolerance. Learn more about egg intolerance.

Adults are more likely to have an allergic reaction to fish and shellfish than children. Some people will get reactions from only certain types of fish, and others can react to all fish. The degree of reaction can vary depending on the type of fish that people eat.

Most people who have an allergy to fish will react to the protein allergen called parvalbumin. Cooking does not destroy these proteins, which means that people can have reactions to both cooked and raw fish.

Fish allergy symptoms

Symptoms of an allergic reaction to fish can include a skin rash. People can also get a runny nose, sneezing, or symptoms of asthma. For people who are allergic to fish, avoiding fish and fish products is key.

An allergy to cow’s milk is one of the most common food allergies in childhood. A person can have a reaction even to small amounts of milk or from eating dairy products.

Some nursing babies will experience colic or eczema if the mother has consumed cow’s milk or eaten dairy products.

Many children will outgrow a milk allergy. A study from the American College of Allergy, Asthma and Immunology (ACAAI) shows that 53% of infants under age one are allergic to milk, but only 15% of adolescents.

Milk allergy symptoms

The symptoms of milk allergy include hives, diarrhea, and vomiting. People can be allergic to two different milk proteins, casein and whey. Many foods that are not obvious milk or dairy products can contain these proteins. People who are allergic to milk should be careful to not drink it or consume any products that may contain milk or dairy.

A milk allergy is not the same as lactose intolerance. People who have lactose intolerance are not allergic to milk. Instead, it means they don’t have enough of an enzyme called lactase, which they need to break down lactose.

Learn more about lactose intolerance.

Allergies to tree nuts are usually lifelong. Along with shellfish and peanut allergies, tree nut allergies are among the most frequent food-induced causes of anaphylaxis. The nuts most likely to lead to allergic reactions are:

  • cashews
  • pistachios
  • walnuts
  • hazelnuts
  • almonds
  • pecans
  • brazil nuts

Sometimes, people with an allergy to one type of nut can also react to other nuts.

Tree nut allergy symptoms

People allergic to tree nuts can react in many different ways. Symptoms can include hives, vomiting, low blood pressure, or difficulty swallowing. Some people can also experience itching in the mouth, throat, skin, eyes, or other parts of the body. People allergic to tree nuts should avoid eating them or any foods that may contain them.

Learn more about tree nut allergies.

Peanuts are one of the most common causes of food allergy. People allergic to peanuts will usually be allergic all their lives. Nevertheless, recent research shows that as many as 20% of allergic people may outgrow the allergy. A peanut-caused allergic reaction can be severe, and even traces of peanut can be enough to cause a reaction in people who are sensitive.

A small minority of people with peanut allergies might also react to other legumes such as green peas.

Even though peanuts aren’t tree nuts, people with a peanut allergy are sometimes allergic to some tree nuts as well.

Cooking some allergy-causing foods can eliminate the reaction-causing proteins, but studies show that is probably not the case when it comes to roasting, boiling, or frying peanuts.

Experts believe peanut oil is safe for people with peanut allergies because the proteins that cause allergic reactions are removed during the manufacturing process. However, cold-pressed or unrefined peanut oil can contain small amounts of peanut allergens, which can cause a reaction in people who are sensitive.

Peanut allergy symptoms

People allergic to peanuts will experience many of the same symptoms as people allergic to other foods. These symptoms include stomach problems, weak pulse, swelling, hives, dizziness, and confusion.

Allergic people should be careful before consuming peanuts in any form.

An allergy to shellfish is different than an allergy to fish. Many types of shellfish can cause reactions in people who are allergic, including:

  • shrimp
  • lobster
  • crab
  • crayfish
  • oysters
  • scallops
  • mussels
  • clams

People who are allergic to one type of shellfish often find that they react to other types as well.

Shellfish allergy symptoms

People having an allergic reaction to shellfish can experience vomiting, wheezing, and other symptoms common to the majority of food allergies.

A shellfish allergy can often cause severe reactions, and some people can even react to the vapors from cooking shellfish. As with other food allergies, people should avoid coming in contact with shellfish if they have this allergy.

Learn more about shellfish allergy.

Soybean allergy is a common childhood allergy. Most people who are allergic to soybeans are under 3 years old, but occasionally adults are allergic to soybean.

Soybean allergy symptoms

People allergic to soybeans can experience rashes, vomiting, diarrhea, and stomach cramps. Rarely, soybeans may cause anaphylaxis.

Avoiding soybeans is key to avoiding a reaction. Some people can eat highly refined soybean oil or foods that contain soy lecithin, a substance derived during soybean processing. Allergic people should consult a doctor to check if this is safe for them.

Wheat allergy is another common pediatric food allergy. Approximately 65% of children will outgrow it by age 12.

One of the main allergens in wheat is a protein called gliadin, which is found in gluten. Because of this, people with a wheat allergy may need to eat a gluten-free diet.

Wheat allergy symptoms

People rarely get anaphylaxis from a wheat allergy, but this can happen occasionally. Symptoms of a wheat allergy also include asthmatic symptoms, digestion problems, and rashes.

As with all food allergies, people who suspect they may be allergic to wheat will need to speak with their doctor before altering their diet. Wheat allergy is not the same as celiac disease, which is an autoimmune condition.

Learn more about wheat allergy.

An allergy to sesame can be severe, especially for children. According to the Food and Drug Administration (FDA), only about 20-30% of children with this allergy will outgrow it by adulthood.

Previously, this allergy wasn’t as well known. But in April 2021, the U.S. government passed the Food Allergy Safety, Treatment, Education, and Research (FASTER) Act, which declared sesame the ninth officially recognized major food allergen in the country. This law means that manufacturers now have to label sesame as a potential allergen when it’s an ingredient in produced food.

Sesame allergy symptoms

Like other food allergies, an allergy to sesame can cause a range of symptoms. These can include rashes, hives, or vomiting. In severe cases, it can also lead to throat swelling and anaphylaxis.

Since these symptoms can overlap with symptoms of other food allergies, it can be hard to diagnose a sesame allergy reliably. But a 2019 study in Pediatric Allergy and Immunology showed that out of 88 children who had confirmed food allergies, 17% were allergic to sesame. Overall, estimates suggest that about 1.1 million Americans are allergic to sesame.

In addition to these major food allergies, people can be allergic to almost any food. There are many other allergies that affect a lot of people, including allergies to other cereals besides wheat, like oats. Other foods that can cause allergies include coconut, fruit and vegetables, meat, and spices like cinnamon.

The best way for a person to avoid an allergic reaction is to not eat any foods that they are sensitive to. This can be challenging because many food products contain allergy-causing foods like dairy, eggs, and peanuts.

Allergic people should always check the ingredients of any store-bought foods before consuming them.