More Americans claim to have food allergies than ever before, but a report published in 2016 from the National Academy of Sciences says that it’s hard to know how many people in the U.S. actually have food allergies. Although many healthcare professionals involved in patient care agree that an increase has occurred, specifying its actual extent is complicated by factors such as inconsistent data or studies that use variable methods.
Part of the problem is that many people self-diagnose and can easily misinterpret their symptoms. Food allergies can be mistaken for gluten sensitivity or lactose intolerance, e.g., neither of which fits the medical definition of an allergy. 
Dr. Virginia Stallings, a board-certified nutrition pediatrician at the Children’s Hospital of Philadelphia and the chair of the committee that wrote the report, said:
“There are a lot of misconceptions about what a food allergy is.”
One of the ways in which a misinterpretation arises is when parents introduce milk or another new food into their child’s diet, and then see that the child has an upset stomach or other gastrointestinal symptoms. These symptoms could indicate lactose intolerance, but the parents may suspect a food allergy. In reality, food intolerance and food allergy are two different conditions.
“The reason food allergy symptoms are often confused with other [conditions] such as lactose intolerance is because there’s an overlap in some of the symptoms.”
The panel estimated that about 5% of U.S. children have legitimate food allergies, and wrote that:
“Eight food groups are considered to be major allergens. These are milk, egg, peanut, tree nuts, wheat, soy, fish, and crustacean shellfish.” 
“Questions persist about whether food allergy prevalence has been on the rise within the past two decades and why. The current data do not unequivocally support the occurrence of such a rise.”
The Definition of a Food Allergy
Allergies are caused by an immune response to a normally-harmless food or other substance. Allergies typically cause hives and swelling or gastrointestinal distress. Severe food allergies can be life-threatening. In contrast, someone with lactose intolerance can’t easily digest the natural sugar in milk, and the condition is not life-threatening – just highly uncomfortable. 
As the American Academy of Pediatrics points out, “while lactose intolerance can cause a great deal of discomfort, it will not produce a life-threatening reaction such as anaphylaxis.” 
Anaphylaxis (severe allergic reaction) can cause someone to go into shock within seconds or minutes of contact with the food or substance (latex, e.g.) that he or she is allergic to. A sudden drop in blood pressure occurs; and the airways narrow, which blocks normal breathing. Other symptoms of anaphylactic shock can include a rapid, weak pulse a skin rash, and nausea and vomiting. 
Another problem making it difficult to determine how many people have food allergies is the fact that diagnosing food allergies can be complicated. Stallings said that there’s no single skin or blood test that lets physicians accurately determine whether a person has an allergy to a specific food. 
Advice for Parents
Parents should seek immediate medical attention if their child’s lips swell or the child has difficulty breathing. When the symptoms are milder, parents should see an expert, such as a pediatric allergist, instead of declaring that the child has an allergy.
Bruce Lanser, who directs the pediatric food allergy program at National Jewish Health in Denver, said:
“We unfortunately see kids avoiding a food unnecessarily because of some fear of a potential allergy.”
The best diagnostic tool at experts’ disposal is an oral food challenge, according to Lanser. Under medical supervision, patients eat small amounts of the food they are suspected of being allergic to. Lanser explained:
“We start with a small amount of food and slowly give increasing doses up to a full serving.”
If the patient has a reaction during the test, “obviously we stop and treat,” he said.
The authors of the report wrote:
“The patient’s medical history and other test results, such as from a skin prick test, can suggest the likelihood of a food allergy, but in some cases an oral food challenge – which involves a gradual, medically supervised ingestion of increasingly larger doses of the food being tested as a possible allergen – is needed to confirm diagnosis. ” 
That’s a lot of work to confirm an allergy, so people often just go on a hunch.
Lanser said he tests his patients once a year to see if they’ve outgrown their food allergies. And they often have. Said Lanser:
“Milk and egg allergy are commonly outgrown. About 1 in 5 people outgrow their peanut allergy.” 
Food Allergy Safety – 4 Recommendations
The authors of the new report recommend more research to determine the prevalence of food allergies. The report also includes many recommendations for addressing food-allergy safety:
- 1. Kids who have severe symptoms of a food allergy may require an epinephrine injection. In many schools, only a school nurse is trained to give shots. The report recommends that other administrators and teachers also be trained to administer epinephrine in case of emergency.
- 2. New parents should be better informed about allergy prevention. Recent studies have suggested that introducing potential allergy-triggering foods like peanut butter before age 1 is more likely to protect at-risk children than waiting to try those foods when children get older, as was recommended in the past.
- 3. Health professionals and the public should receive better education concerning differences between true food allergies and other disorders (lactose intolerance and gluten sensitivity, e.g.) that are often mistaken for allergies.
- 4. Restaurant workers, first responders, and others should receive better training in helping people avoid foods they’re allergic to, and in treating severe allergic reactions with epinephrine, often sold as an EpiPen. 
 NBC News
 Mayo Clinic
 The Boston Globe