Are Food Allergies on the Rise?
It is often claimed that food allergies have been on the rise for years. According to the U.S. Centers for Disease Control and Prevention (CDC), 4 million children currently suffer from food allergies, the most common of which are to peanuts, tree nuts, eggs, milk, wheat, soy, fish, and crustacean shellfish. However, a new report published by the National Academies of Science demonstrates that there is a lot of confusion over the prevalence of food allergies, and experts are not sure if the frequency of food allergies is actually changing.
The report, which was put together by a team of 15 physicians who were appointed by the National Academies, helps to clarify why it is so difficult to know the actual incidence of food allergy. One major complication is that incidence is constantly changing, even within individuals. Many kids outgrow their allergies, while adults often acquire them. While allergies to eggs and milk are very commonly outgrown, about 20% of children will outgrow peanut allergies. At the same time, we often hear of adults suddenly becoming allergic to shellfish. Tracking the proportion of the population that endures food allergies becomes increasingly difficult when the allergy status of individual patients changes over time.
Another major challenge for understanding the prevalence of food allergies is related to difficulties with diagnosis. First, there is no perfect tool for diagnosing food allergies. Skin prick tests may be used to determine how likely a food allergy may be, though oral food challenge tests are generally used to confirm a diagnosis. With oral food challenge, the healthcare provider exposes the patient to small amounts of the potential allergen to see if the patient reacts. If the patient reacts, the test is stopped, and the patient is treated.
Another barrier for proper diagnosis is that patients often self diagnose and do not properly interpret their symptoms. The overlap in symptoms between allergies and other conditions, such as lactose intolerance, can make it difficult for patients, their families, and even their physicians to delineate the root cause. Gastrointestinal distress is the most common overlapping symptom, and many parents who notice that a food causes an upset stomach in their child assumes that the child has an allergy. Unfortunately, in these cases, kids will often end up unnecessarily avoiding foods. This type of behavior runs counter to recommendations based on the recent consensus that exposing young children to potential allergens earlier has a protective effect against developing allergies.
The main distinguishing feature between food allergies and lactose intolerance is that food allergies are life threatening, whereas lactose intolerance is not. Food allergies are also more likely to cause itchiness of the mouth, dizziness, and swelling of the lips and tongue, so those types of symptoms may indicate that a reaction is not simply due to lactose intolerance.
The report from the National Academies made a number of suggestions for increasing safety for those with food allergies. One idea was to have schools train personnel other than the school nurse in how to administer drugs like epinephrine that could be lifesaving when a student suffers a severe allergic reaction that may lead to anaphylaxis. They also made recommendations related to research, including
including enhancing research efforts to understand the actual prevalence of food allergies and what contributes to them.