Q: Growing up, I don’t remember such a big deal being made about food allergies, but it comes up in schools, day cares and play groups all the time now. Why?
A: There are probably multiple reasons for the observation that you have made. The difference is related to our growing knowledge about allergic reactions, an increased public awareness of them, belonging to a lawsuit-conscious society and an actual increase in allergies in children.
The perceived prevalence of food allergies is quite high – 15 percent of parents report that their child has a food allergy, but the actual prevalence among children in the U.S. is about eight percent. The most common allergic dietary triggers are milk, seafood, peanuts, tree nuts and eggs. In previous decades, the estimate of food allergies in children was somewhere around 3 to 4 percent. It is likely that there has been an increase in the actual number of children with food allergies, but this increase may be small in comparison to the increase in the awareness and recognition of both severe and non-severe presentations of these conditions.
There are different types of food allergies – the typically-feared type of allergy is mediated by an antibody called IgE and is related to histamines. This is the type of allergy that can lead to anaphylaxis (which can lead to shock and difficulty breathing and can be fatal). These are the children for whom all the strict laws at school and day care are created, as even a slight exposure to the trigger can cause very serious illness in a very short period of time.
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Approximately 18 percent of students with food allergies will have at least one reaction in school over the course of two years. This does not mean that one-fifth of all children diagnosed with allergies at some time in their life will have a severe allergic reaction over a two-year span, however, as many children outgrow their allergies by the time they are in school (especially true of allergies to milk and eggs) and often the patients with less severe allergies do in fact outgrow them by school age. There is growing research (a large amount of which is done locally and is extraordinarily promising) evaluating ways to help “cure” children of their allergies.
There are other types of allergies that cause symptoms that are less life-threatening, such as abdominal pain, vomiting, diarrhea, bloody stools, and rash. These often have different mechanisms and the typical allergy testing that’s done by an allergist may not pick these up. Cow’s milk-protein allergy is a common example of this. The treatment of these types of allergies is very different and mostly limited to avoidance of the trigger (cases like this do not require, for instance, an injection of epinephrine after an exposure/reaction). Fortunately, allergies that cause less life-threatening symptoms do not tend to lead to emergencies.
If you have a question about your child's health or happiness, ask Dr. Eichner or any of our experts by sending email to firstname.lastname@example.org.
Brian Eichner is a general pediatrician and assistant professor of Pediatrics at Duke Children's Primary Care-Roxboro Street in Durham. He enjoys providing care for children who are healthy as well as those with complex medical conditions. Dr. Eichner also serves as the medical director of the Duke Pediatric Diagnostic Clinic. He and his wife have lived in the Triangle since 2006.