We all know what it’s like to experience a sour stomach or minor indigestion after overindulging or eating something that doesn’t quite agree with us. But for people with food allergies, eating the wrong thing can cause a much more troubling physical reaction, ranging in severity from minor irritation in the mouth to full-blown, potentially life-threatening anaphylaxis.
How common are food allergies? According to the Asthma and Allergy Foundation of America (AAFA), as of 2021, about 20 million people have food allergies in the US, including about 16 million (6.2%) adults and about 4 million (5.8%) children. Food allergy symptoms can appear at any age, and it’s possible to develop an allergy to foods one has eaten with no problems for years.
What exactly is a food allergy?
A food allergy can be defined as a misplaced immune response. Essentially, the body’s immune system mistakenly perceives a protein in a particular food as an invader and launches a counterattack, releasing chemicals such as histamine in an attempt to eliminate it. As a result, the allergic individual can experience symptoms such as tingling in the mouth, swelling of the tongue and throat, hives, abdominal cramps, diarrhea, vomiting, breathing difficulty, drop in blood pressure, loss of consciousness, and even death.
It’s important to note that a food allergy is not the same thing as a food intolerance. People who have a food intolerance do not have an immunological response when they consume a particular food. Rather, they are unable to digest that particular food properly. The classic example is lactose intolerance, which occurs in people who lack the necessary enzyme to digest milk sugar, or lactose.
Common food allergens
The American College of Allergy, Asthma & Immunology (ACAAI) attributes approximately 90 percent of all food-related allergic reactions to eight particular foods—eggs, milk and dairy, peanuts, tree nuts, fish, shellfish, wheat, and soy. According to the FDA, sesame, which is present in many popular dishes such as hummus, is the ninth most common food allergen and was just added to that list in January of this year.
In terms of reaction severity, peanuts rank especially high on the list, being one of the food allergens most commonly associated with anaphylaxis—a potentially deadly condition that requires immediate treatment. Symptoms of anaphylaxis may include impaired breathing, swelling of the throat, a sudden drop in blood pressure, pale skin or blue lips, fainting, and dizziness.
Food allergen cross-reactivity It’s interesting to note that if someone is allergic to a particular food, there’s a good chance that he or she will react to other foods containing similar antigens (substances that induce an immune response in the body). This phenomenon is known as food allergen cross-reactivity. For example, according to the American Academy of Allergy, Asthma & Immunology (AAAAI), someone who is allergic to birch tree pollen might also experience a reaction when eating apples.
How are food allergies diagnosed?
In most cases, food allergies are identified after the allergic individual ingests a particular food and experiences some type of reaction. However, allergists can perform certain tests to aid in diagnosis. The National Institute of Allergy and Infectious Diseases (NIAID) identifies two particular tests as the most frequently used food allergy diagnostics: the skin-prick test and the allergy blood test.
With the skin-prick test, a drop containing the antigen from the food being tested is placed on the patient’s skin and the skin is pricked with a probe. A small bump, similar to a mosquito bite, will soon form at the site if the patient is potentially allergic to the food antigen. With the allergy blood test, a blood sample is taken from the patient and sent to a laboratory where it is tested for IgE antibodies specific to the particular food being tested.
How are food allergies treated?
Unfortunately, there is no treatment that will cure food allergies. Some progress has been made in the area of immunotherapy, most notably for reducing sensitivity in people with peanut allergy. However, the primary method for managing food allergies remains strict avoidance of the food that is known to cause a reaction. If exposure to an allergy-causing food does occur, antihistamines may be helpful in managing minor symptoms. However, they cannot treat a severe reaction. In people with severe food allergies, a device for auto-injecting epinephrine (i.e., EpiPen) is usually prescribed and kept on hand at all times to control a severe reaction if one should occur.
With back-to-school season right around the corner, it’s important for parents of children with known food allergies to make their kids’ teachers and school aware of the problem so they know what potential symptoms to watch for and what steps can be taken to reduce the risk of exposure during lunch and snack times. Parents should also verify that any supervising adults at the school understand how to use an epinephrine auto-injector properly. ✲
