Understanding food allergies | The Austin Diagnostic Clinic
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Understanding food allergies

no peanut butter

Common foods may cause allergic reactions

Ever wonder why some packaged foods include the warning “made in a facility that processes nuts?” There’s a very good reason—some people can develop a life-threatening allergic reaction to eating tree nuts called anaphylaxis. There are a number of foods that can cause serious allergic reactions in certain people, says Thomas Smith, M.D., an ADC allergist and immunologist.

“From peanuts to dairy products to shellfish, there are several primary sources of food allergies affecting some 15 million Americans” says Dr. Smith.

A food allergy occurs when a person’s immune system mistakenly attacks a food protein. Dr. Smith says allergy symptoms can range from mild reactions like rashes, hives, itching and swelling, to severe, potentially fatal issues such as trouble breathing or loss of consciousness.

Understanding food allergies

People with food allergy almost always have clear cut symptoms when eating a particular food. They usually know the food they are allergic to, or they at least have figured out a short list of possibilities.

Either way, it’s a good idea to see an allergist to determine whether a food allergy exists and what food should be avoided. This is done by a review of a person’s history of symptoms and checking for food allergies with a skin test.

It is also common for people to experience an adverse effect from a food that is not an allergy. Distinguishing this is important because adverse effects that are not allergic do not carry the same risk of severe reactions, explains Dr. Smith.

“Once we have identified the source of a food allergy, unfortunately the only way to prevent an allergic reaction is to avoid the food. There is no cure for a food allergy,” says Dr. Smith. “If you are unsure about whether a particular food is safe, it’s always a good idea to call the manufacturer for more information.”

If a person unknowingly eats a food they are allergic to, the best option is to administer epinephrine, also called adrenaline. This is the medication of choice for controlling a severe reaction. It is available by prescription as a self-injectable device called EpiPen or Twinject. Dr. Smith says patients should always have two doses available because some reactions that go away with one dose of epinephrine may return, requiring a second dose.

Parents with children with food allergies understandably are concerned when their children are at school. Virtually every state, including Texas, allows children to carry epinephrine during school with appropriate consent. Legislation passed last year in Texas, meanwhile, calls for the creation of food allergy management guidelines for schools.

Primary sources of food allergies

The six most common foods causing allergy in children are milk, eggs, peanuts, wheat, peas, and soy. Tree nuts, fish, and shellfish are foods commonly causing allergy in children and adults. Allergy to one food occurs most often, while allergy to multiple foods is less likely. Here is a look at the main sources of food allergies in more detail:

  • Peanuts
    Peanuts can trigger a severe allergic reaction depending on how sensitive a person is to peanuts, and the quantity of peanuts consumed. Peanuts may be included in food items such as chili sauce, salad dressing, pizza, peanut cooking oil, egg rolls, and even jelly beans.
  • Tree nuts
    Tree nut allergies affect an estimated 1.8 million Americans and are among the leading causes of fatal and near-fatal reactions to foods. Common types of tree nuts causing allergies include walnuts, almonds, hazelnuts, cashews, pistachios, and Brazil nuts.
  • Milk
    About 2.5 percent of children younger than age 3 are allergic to milk, but most children outgrow milk allergies within a few years.
  • Eggs
    An estimated 1.5 percent of young children have an egg allergy, but experts say most children eventually outgrow it.
  • Wheat
    Wheat allergy is one of the more common food allergies in children. Wheat can be found in many food items such as breads, cakes, breakfast cereals, pasta, crackers, soy sauce and even condiments such as ketchup.
  • Soy
    Although soybean allergies are generally mild, soybeans are used in myriad food items including baked goods, canned tuna, cereals, crackers, infant formulas, sauces, and soups.
  • Seafood
    Nearly 7 million people in the United States are allergic to seafood, including fish and shellfish like shrimp, crab, and lobster. Salmon, tuna, and halibut are the most common kinds of fish people are allergic to. Seafood allergy is considered a lifelong condition and about 40 percent of those with a seafood allergy first experience an allergic reaction as an adult.

Beyond the usual food allergy suspects

Dr. Smith says that while these seven types of food account for 90 percent of all food allergies, a person can be allergic to virtually any food.  Other potential allergy-prone foods include corn, seeds, meats, and spices such as caraway, coriander, garlic, and mustard. Allergic reactions can also occur with fresh fruits and vegetables such as apples, carrots, peaches, plums, strawberries, tomatoes, and bananas.

“Awareness of a food allergy and early treatment with epinephrine are the most important ingredients in preventing a potentially dangerous reaction,” says Dr. Smith.