(Editor’s Note: This is an online-only article attributed to the October/November 2018 issue.)
Most food allergies develop in children around 6 years of age, says Clifford W. Bassett, MD, FACAAI, FAAAAI, a New York City doctor who specializes in the evaluation and management of allergic disorders affecting children and adults. As many as 7 percent of American children have some allergy to food or ingredients in food.
However, most outgrow these food allergies. Only about 2 percent of American adults suffer from food allergies, with the most common allergies in adults caused by eating peanuts, tree nuts, fish, and shellfish. Skin and blood tests can help determine if someone has a food allergy. If a child is tested and it reveals a food allergy is present, the child should be tested again after a few years. There is a 60 percent chance that the allergy has been lost.
What Causes a Food Allergy?
According to Dr. Bassett, food allergies are caused by allergen-antibody interactions. Simply put, this means that a food allergy occurs when the body’s immune system views a specific food or food ingredient as harmful and reacts by causing symptoms. These reactions may be mild to severe—even deadly—and can include any of the following:
- Skin rash, itching, and hives (the most common signs of a reaction);
- Swelling of the lips, tongue, or throat;
- A variety of respiratory problems;
- Stomach pain and vomiting; and
- A general “getting sick” feeling (for instance, when someone believes they are coming down with the flu).
Reaction severity can depend on the amount of food the person has eaten containing the allergen, what other types of food eaten at the same time, and whether alcohol was consumed while eating. Some consumers are so sensitive to food allergens, even if they inhale air that encounters the allergen, such as peanuts served on an airplane, they can react.
Food allergies can be inherited. Some consumers have a strong predisposition to food allergies because it runs in their family. In addition, environmental factors can also produce food allergies; long-term exposure to tobacco smoke, pesticides, even stress can contribute to different types of allergic reactions.
It is believed that eight kinds of foods are responsible for more than 90 percent of all food allergies in children. These are milk, eggs, peanuts (which has increased significantly in the past decade), tree nuts (almonds, Brazil nuts, cashews, chestnuts, macadamia nuts, pecans, pistachios, walnuts, and others), fish, shellfish, soy, and wheat.
There also appears to be the so-called “families of foods” that cause allergies. For instance, if a child is allergic to almonds or pecans, there is an excellent chance that the child is also allergic to peanut butter, peanut oil, and many if not most of the other tree nuts mentioned above. These families of foods can be very broad; a child with an egg allergy may also be at higher risk for having a peanut allergy.
Preventing Allergic Reactions
How should a person experiencing a food allergy reaction be treated? If the response is acute and the person is taken to an emergency room, an injection of epinephrine (adrenaline) is usually given. This can help decrease the allergic reaction, however, epinephrine has its own side effects, some of which can be severe.
There are also some prescription drugs that can help treat people and minimize reactions to food allergies. However, these may not work for everyone. Ultimately, the best treatment is avoidance: Those who have a known food allergy are advised to avoid foods and food ingredients that cause the reactions, and this is where proper food labeling comes into play.