Food Allergy Symptoms, Information, and Types

What is a Food Allergy?

Did you know that 1 in 13 children in the U.S. (or approximately 32 million Americans) is diagnosed with a food allergy? And while not all conditions are severe or life threatening, a food allergy reaction sends someone to the emergency room every three minutes. That’s a staggering statistic, and one of the reasons the Southern California Food Allergy Institute is a cutting-edge clinical care and research center that is committed to revolutionizing food allergy treatment.

But first, what even is a food allergy? A food allergy is an immune response to food that’s otherwise harmless. A food allergy is not a food sensitivity or intolerance, which is often associated with the digestive system. Whether you suspect your child has a food allergy, or your family has been managing food allergies for some time now, it’s important to recognize the symptoms of common food allergies and understand the different types.

Common Food Allergies and Symptoms

Gluten Allergy

There are many terms used to describe the different ways a body may respond to gluten, a protein found in wheat, barley, and rye. Some people are allergic to wheat, but that is not the same as a gluten allergy. In fact, there really is no such thing as a “gluten allergy,” and it is more accurate to refer to it as a “gluten intolerance” or “non-celiac gluten sensitivity.”

Celiac disease, on the other hand, is an autoimmune disorder. When a person with celiac disease ingests gluten, an immune response is triggered in the small intestine, and over time, this reaction damages the small intestine’s lining and prevents it from absorbing some nutrients.

Symptoms of celiac disease include severe diarrhea after eating foods that contain gluten, rash, severe weight loss or failure to properly gain weight, and abdominal pain. In young children, poor weight gain may not be accompanied by pain, though other symptoms may also be present. If not properly diagnosed and treated, celiac disease can lead to serious complications.

Oral Allergy Syndrome (Fruits and Vegetables)

Oral Allergy Syndrome (OAS), also known as Pollen Food Allergy Syndrome (PFAS), is caused by a cross-reactivity between plant proteins from pollen and fruits or vegetables. Cross-reactivity occurs when the proteins in one substance (in this case, pollen) are similar to the proteins found in another substance (fruits/vegetables), so the immune system sees them as the same and responds similarly to both.

As the name suggests, OAS is an allergic reaction that is confined to the lips, mouth, and throat, and it typically first presents in older children, teens, and young adults who have been eating the (raw) fruits or vegetables in question for years without any issues.

Itchy mouth, scratchy throat, or swelling of the lips, mouth, tongue, and throat are the most common symptoms, though itchy ears and hives on the mouth are sometimes reported. People affected by OAS can usually eat the same fruits or vegetables in cooked form, since the heating process distorts the proteins, and the immune system no longer recognizes the food and produces a response.

Milk Allergy/Lactose Intolerance

A milk allergy is one of the most common food allergies in infants and children, and it occurs when the body’s immune system responds abnormally to milk and products containing milk. While cow’s milk is the usual cause of a milk allergy, milk from sheep, goats, buffalo, and other mammals can also cause a reaction.

Milk is the third most common food (after peanuts and tree nuts) to cause anaphylaxis, a life-threatening reaction that narrows the airways and can block breathing. Other symptoms of a milk allergy include swelling of the lips, mouth, tongue, or face, skin reactions (i.e. hives, a rash, or red, itchy skin), as well as nasal congestion, sneezing, runny nose, itchy eyes, coughing, or wheezing.

Lactose intolerance is not the same as a milk allergy, and it happens when the body can’t break down or digest lactose—a sugar found in milk and milk products—because the small intestine does not produce enough of a digestive enzyme called lactase. Symptoms of a lactose intolerance are more digestive in nature and often include abdominal cramps and pain, nausea, bloating, gas, and diarrhea.

Egg Allergy

An egg allergy occurs when the body’s immune system reacts to proteins found in egg whites and/or yolks, and it is one of the most common food allergies. Experts estimate that as many as 2% of children are allergic to eggs, though fortunately, studies show that the majority (about 70%) of children outgrow the condition by age 16. People with an allergy to chicken eggs may also be allergic to other types of eggs, such as goose, duck, turkey, or quail.

Symptoms of an egg allergy vary and can range from a mild rash to anaphylaxis, and can result from ingesting or even just touching eggs. Other signs of an egg allergy include skin reactions (such as swelling, a rash, hives, or eczema), wheezing or difficulty breathing, runny nose and sneezing, red or watery eyes, as well as stomach pain, nausea, vomiting, or diarrhea—among others

Shellfish/Seafood Allergy

Shellfish allergy is the immune system’s abnormal response to proteins in certain marine animals including crustaceans, which include crab, lobster, crayfish, shrimp, and prawn, and mollusks, which include squid, snails, clams, oysters, and scallops.

Some people with a shellfish allergy react to all shellfish, while others react to only certain kinds. Reactions from a shellfish allergy range from mild symptoms like hives or a stuffy nose to severe and even life-threatening responses including anaphylaxis. Although anyone can develop a shellfish allergy, it’s more common in adults, particularly women. Among children, shellfish allergy is more common in boys.

The other major group of seafood that can trigger an allergic response are vertebrates, or fish with a backbone. This includes bass, flounder, cod, salmon, mackerel, sardines, herring, anchovies, tuna, trout, haddock, John Dory, eels, and rays.

Similar to a shellfish allergy, many allergic reactions to seafood are mild (e.g. hives, tingling of the throat and mouth); however, swelling, digestive issues (i.e. vomiting and diarrhea), and difficulty breathing—as well as anaphylaxis—are also possible.

Peanut/Tree Nut Allergy

Peanuts are the most common food allergen as well as the most common cause of food-induced anaphylaxis. For some people with a peanut allergy, even small amounts of peanuts can trigger a life-threatening reaction, and unfortunately, peanut allergies in children have been increasing in recent years.

Tree nut allergies are also very common in both children and adults, and the most often reported are allergies to walnut, almond, hazelnut, pecan, cashew, and pistachio. About 50% of children that are allergic to one tree nut are allergic to another as well.

An allergic response to peanuts and tree nuts typically occurs within minutes after exposure and can include:

  • Skin reactions, such as hives, redness, or swelling
  • Itching or tingling in or around the mouth and throat
  • Digestive problems (i.e. diarrhea, stomach cramps, nausea, and/or vomiting)
  • Tightening of the throat
  • Shortness of breath or wheezing
  • Runny nose

It’s also important to know the signs and symptoms of anaphylaxis, and be prepared in the event of this medical emergency:

  • Constriction of airways
  • Swelling of the throat that makes breathing difficult
  • A severe drop in blood pressure (also known as shock)
  • Rapid pulse
  • Dizziness, lightheadedness, or loss of consciousness

Emergency treatment is critical for anaphylaxis. Once the reaction starts, the drug epinephrine is the only effective treatment, and it must be injected within minutes of the symptoms. You must also dial 911 and request emergency help immediately after injecting with epinephrine.

Casein Allergy

Casein allergy is another term used to describe a milk or dairy allergy. Casein is the protein found in milk and other dairy products that can trigger an immune response when the body mistakenly thinks casein is harmful and produces allergic (IgE) antibodies for protection.

When these antibodies and casein interact, the body releases chemicals, such as histamine, that can cause a range of symptoms within minutes: swelling of the lips, mouth, tongue, or face; skin reactions, such as hives, a rash, or red, itchy skin; and nasal congestion, sneezing, runny nose, itchy eyes, coughing, or wheezing.

Never before have there been more resources for families that are navigating food allergies, and while there is no “cure,” there are many steps you can take to manage and treat reaction symptoms. If you suspect your child may have a food allergy, you should first stop giving your child that particular food (and anything else in the same category), and contact their doctor.

Before any test can be conducted, a detailed clinical history must be completed to assess your child’s reaction and determine if it is consistent with a food allergy. If a diagnosis is suspected, more objective testing will follow.

Here at the Southern California Food Allergy Institute, we are revolutionizing food allergy treatment through our Tolerance Induction Program (TIP™). While avoidance is commonly thought of as the only way to “manage” a food allergy, there is another option to go beyond avoidance and reach food freedom.

Unlike other therapies, such as OIT (Oral Immunotherapy), TIP™ uses trillions of data points to create customized treatment plans for each child. Their allergies are mapped out to form an individualized program that builds tolerance to the unique proteins each child is allergic to, all before introducing their most anaphylactic allergen. This ensures patient safety, and over time, alters their immune system to not react to their allergens.

Learn more about how TIP™ has treated over 12,000 children with a 99% success rate, giving people a life of food freedom where they can eat whatever they want, whenever they want, without fear of reaction.