Demystifying food allergies: Your top 10 questions answered

Bergen Medical Associates’ Allergist, Dr. Margaret Co, reviews the key facts about food allergies


An estimated 5% of the U.S. population has a true food allergy and for these millions of people, the risk of a reaction can be a scary proposition. But what exactly is a food allergy and how can it be treated or managed?

Following, Margaret Co, MD, allergist and immunologist at Bergen Medical Associates — which has six offices throughout Bergen County — answers some of the most popular questions about food allergies:

What is a food allergy?

Dr. Co: A food allergy refers to a medical condition in which exposure to a food triggers a harmful immune response. This response, called an allergic reaction, occurs because the immune system attacks proteins in the food that are normally harmless. People often confuse food allergies with food insensitivities or intolerance, which are not caused by our immune system. In fact, nearly 20% of adults believe that they’re food-allergic when many of them are actually intolerant (such as with lactose intolerance) or sensitive to a food (such as with a chemical sensitivity to caffeine or MSG). People may also feel sick after eating certain foods (bloating, heartburn, vomiting, etc.), but this doesn’t necessarily mean an allergy.

What are some of the highest-allergy foods?

Dr. Co: These include cow’s milk, eggs, wheat, soy, peanuts, tree nuts, fish, shellfish and sesame, and people can be allergic to one or more of these foods. For example, if they’re allergic to peanuts, they may be more likely to be allergic to tree nuts as well.

What are the symptoms of a food allergy?

Dr. Co: Symptoms can range from mild reactions (including hives; swelling of the skin, lips or face; a runny nose; sneezing; or itchy or watery eyes) to severe ones (such as anaphylaxis, which can involve swelling of the throat, wheezing, trouble breathing, coughing, vomiting, diarrhea, dizziness, fainting and even death). Symptoms can differ from person to person, even among the same person with the same food.

How fast do symptoms develop?

Dr. Co: In the immediate type of food allergy in which a person makes high levels of IgE (allergic antibody) to a food, symptoms can occur rapidly and progress to anaphylaxis. This type of reaction occurs within minutes to an hour after ingestion and can occur even if the smallest amount of food is ingested. Other types of food allergy are more delayed and can occur a few hours after ingestion.

Is there a test for food allergies?

Dr. Co: Skin tests (in which the skin is pricked with a device that contains that food) are the most accurate. But if a person has had an anaphylactic response, an allergist may do a blood test instead, which checks for the presence of antibodies (IgE) made by the body in response to a particular food. Because both skin and blood testing can generate false positive and false negative results, they need to be carefully interpreted in conjunction with the patient’s history. The gold standard for diagnosing whether one is allergic to a food or not is an oral challenge where the suspected food is given to a patient under close medical supervision.

How is an allergic reaction treated?

Dr. Co: For mild symptoms, we advise patients to take an antihistamine like Benadryl or Zyrtec; more severe symptoms may require epinephrine, which reverses many of the symptoms of anaphylaxis. Epinephrine is available in a self-injecting device, or auto-injector, that comes in many forms (one of which talks to you while you’re using it) and which patients need to carry with them at all times. People with food allergies usually have an action plan and are guided as to when to employ it. They should seek medical help if symptoms are severe.

Can allergic reactions be prevented?

Dr. Co: Treatment for a food allergy is strict avoidance — that’s the best preventative medicine available. We teach patients to read food labels, instruct restaurants of dietary restrictions and even wear a medic alert bracelet to inform others if necessary.

How will my life be impacted if I’m diagnosed with a food allergy?

Dr. Co: A diagnosis of food allergy can impact one’s quality of life tremendously. For example, it may lead people to become fearful of eating out or cause children to be very hesitant to try new foods and become even more “picky eaters.” For those reasons, it’s important to diagnose a food allergy accurately. While some food allergies can remain with you for the rest of your life, you can still live a normal life — you just need to make some changes, educate yourself on ingredients and the different names they go by, and practice avoidance.

Is there any treatment to reduce the chance of a serious reaction?

Dr. Co: Aside from strict avoidance and treatment with medication, one way we can induce tolerance to foods over time is through oral immunotherapy — essentially, giving a person a food they’re allergic to in small, incremental doses to increase the body’s tolerance. In January 2020, the FDA approved the first biologic drug for peanut oral immunotherapy for 4-to-17-year-olds; it involves the patient’s ingestion of peanut protein in increasing doses. To ensure that treatment is administered safely, both the doctor and the patient have to be enrolled in a risk mitigation (REMS) program. In one study, up to 70% of patients who completed treatment could eat up to two peanut kernels with only mild symptoms compared to a placebo, so this approach can potentially help many people to avoid life-threatening allergic reactions.

Is there any way to prevent a food allergy from occurring in the first place?

Dr. Co: Studies suggest that there’s a period in infancy where, if a high-allergy food is introduced to a child at high risk of developing a food allergy, the child will develop tolerance, not an allergy — e.g., early introduction may decrease the risk of developing an allergy. Allergists now suggest screening infants who might be at risk of a peanut allergy with a blood or skin test; a recommendation will be made based on the results. For infants with no risk, avoidance of feeding peanuts isn’t recommended; most parents, with guidance from their pediatrician, may introduce peanuts at home after four to six months as long as the baby is ready to eat solid foods and tolerates other foods.

“Overall, if you suspect that you have a food allergy, see an allergist to get a true diagnosis because it can be fatal,” concluded Dr. Co. “But with knowledge and discipline, food allergies can absolutely be treated and managed.”

For More Information:

With offices in Emerson, Paramus (2), Ridgewood, Northvale and Montvale, Bergen Medical Associates offers primary care and 12 areas of specialized care. Patients enjoy the “one-stop shopping” approach where so many medical services are provided under one umbrella. The multispecialty group fosters an environment of collaboration among the physicians, which results in a seamless continuum of care for patients. For more information, contact us today or call 201-967-8221.

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