Assessing the Difference Between Food Allergy and Food Sensitivity

Healthcare providers are caring for patients at a pivotal time in the food allergy spectrum

Many of us can look back on our childhood and remember a few foods that we weren’t particularly fond of, but ate them for the sake of, say, being permitted to have our favorite after-dinner dessert. As adults, we may decide to “tolerate” specific foods that represent healthier choices even if we would really prefer to be eating more sweet or savory dishes. We can simply eat said foods — maybe they are the occasional Brussels sprouts, cauliflower, beets or bananas — as we feel inclined, or perhaps in relation to doctor’s orders or a current diet plan.

However, for the millions of U.S. adults and children who experience food intolerance and food allergies, there often is no choice as to selective indulging in certain foods. No, for these children and adults alike, the menu is fairly predictable at all times and places. And if that doesn’t sound limiting enough, consider that most folks who live with food allergies will be allergic to many different foods without much reasoning being offered as to why or how their bodies have become accustomed to allergic responses to certain foods.

“Allergies are possibly caused by the environment, they are possibly genetics, and they are possibly timing of exposure,” said John Oppenheimer, MD, FAAAAI, chief of allergy at Atlantic Health System in New Jersey and professor of clinical medicine at Rutgers University of Medicine and Dentistry of New Jersey. “We’re learning a lot today, and I hope that patients over the next several years will be better able to cope with allergies, and maybe even prevent them.”

For the here and now, nurses and other healthcare providers are caring for patients at a pivotal time in the food allergy spectrum, as some of the previous guidance related to allergy awareness and prevention are being reconsidered. As an example, peanut introduction earlier in newborns was actually shown to dramatically reduce the risk for allergic sensitization for high-risk infants, based on factors including susceptibility to eczema, in what is being called a landmark study — the Learning Early About Peanut (LEAP) study released in February 2015. And while, generally speaking, full-on acceptance of the new guidance is still something that has not been achieved, those speaking with ADVANCE have expressed the opinion that early exposure is the way to go.

“In general, delaying the introduction of foods is no longer recommended,” said Matthew Rank, MD, FAAAAI, associate professor of medicine at the Mayo Clinic, Scottsdale, AZ. What is recommended, not just for the general population but also for healthcare providers, is understanding the difference between a food allergy and having a sensitivity or intolerance to a particular food.

“It’s really important to differentiate allergy from sensitivity,” Oppenheimer said. “Symptoms of an allergic response are nausea, vomiting, diarrhea and hives within minutes of eating a food. The definition of an allergic response is an immediate response — it’s happening rapidly after exposure. Sensitivity is not an allergy at all. It is an intolerance from a totally non-allergic mechanism.”

While the symptoms of intolerance can be similar to those of allergic reactions, the difference that separates sensitivity from allergy is more apparent in the quickness of onset. “An example here is milk,” Oppenheimer related. “People who are milk intolerant have difficulty with their metabolism of lactose — the sugar. So, what happens is they’ll drink milk and them they’ll have diarrhea. That’s a lactose intolerance. And allergic response to milk could be somewhat similar. It could include diarrhea, but often will induce cutaneous hives, worsening eczema, or, occasionally, respiratory or cardiovascular compromise.

From a diagnostics standpoint, the difference between allergy and intolerance can be described by comparing immune system antibody responses of immunoglobulin E (IgE) and immunoglobulin G (IgG), according to Oppenheimer. IgE allergies are those immediate responses that tend to cause the serious symptoms such as difficulty breathing, swelling, hives and anaphylactic shock. IgG antibody responses are much more subtle and can be present for years or one’s entire life without posing a major threat to one’s health. There’s also a distinct difference between what it means to be allergic to a food versus having a sensitivity to a food, and to a further extent there is a clinical difference between a sensitivity and an intolerance, Rank said.

“In general, when we use the term ‘allergy,’ we are saying that there are clinical symptoms associated with exposure to an allergen,” he said. “Sensitivity generally refers to when we perform an allergy test and it is positive. A positive allergy test does not always mean that a patient has an allergy. For example, many children will have a positive test to a food allergen, but they can consume the food and experience no reactions. That child would have a ‘sensitivity.’ An ‘intolerance’ is a term used to broadly classify adverse effects of foods or medicines that don’t act clinically, like a typical allergic reaction. For example, if a patient has increased bloating after eating cauliflower but does not exhibit usual allergic reaction symptoms, they are best classified as ‘intolerant’ to cauliflower. This is important because some patients with allergy can have serious reactions whereas most food intolerances are a bother, but not likely associated with serious adverse effects.”

The most common food allergies, according to the American College of Allergy, Asthma & Immunology are: eggs, milk, peanuts, tree nuts, fish, shellfish, wheat and soy.

A noteworthy example here is the current trend on the awareness of the intake of gluten, a substance found in wheat and other cereal grains that is widely considered to be more related to food intolerance than it is allergy. The concept of gluten ‘allergy’ is often misunderstood,” said Rank. “A true gluten ‘allergy,’ where a patient consumes gluten and immediately has rash, swelling, respiratory symptoms, cardiac symptoms or gastrointestinal symptoms, is extremely rare. There are some patients who have an immunologic reaction to gluten called celiac disease, which most commonly manifests as abdominal bloating and malabsorption, but can also have other system-wide symptoms. However, most patients who report being gluten intolerant do not have either of these disorders. These patients may report feeling better when they adhere to a gluten-free diet, which may be related to eating healthier in general when avoiding gluten, a placebo effect or could be related to an intolerance that is not yet understood in scientific terms. Celiac disease affects about 1 in 100 to 1 in 200 people.”

For nurses, this all adds up to being cognizant of a few specific details.

In the hospital setting, nurses will always want to confirm that food allergies (and drug allergies) are documented and referred to each time is a patient is assessed, during each set of daily rounds and especially to the point that they are reviewed at all times that foods are distributed, Oppenheimer warned.

“There are reports all the time of people in the hospital, unfortunately, getting a food they’ve been trying to avoid; so I always think of the nurse as being a very important part of that healthcare team to ensure no mistakes are made,” he said.

For those in the pediatric setting, maintaining an open dialogue with the parents, guardians and family is advised, as is fostering conversation about the most recent guidelines in the literature and, perhaps, including the collaboration of an allergist—especially as it relates to confirming diagnosis of a specific allergy. According to the organization FARE (Food Allergy Research & Education), the most important risk factors to consider in pediatrics include: age (young children are more likely to develop food allergies than older children or adults; family history (having a parent or sibling with a food allergy increases risk; having another food allergy (those living with food allergies tend to have more than one; and having a related medical condition (some people develop a cluster of allergic diseases including eczema, food allergy, allergic rhinitis and asthma).

The American Academy of Allergy, Asthma & Immunology offers copious advice on how to introduce to children types of foods that are said to be highly allergenic. For further information, visit

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