This is the season when we typically think about allergies as they relate to pollen and all the flowers that are finally blooming, but food allergies are also a hot topic of conversation. If you, or anyone you know, has a food allergy, you’re keenly aware of what a serious problem this can be. It seems like we hear more and more about food allergies these days, but that may be a consequence of having a 24-hour news cycle. Are food allergies on the rise? What can we do about this? Inquiring minds want to know.
I caught up with my good friend and allergist Dr. John Overholt recently, and here’s what he has to say:
Dr. John Overholt:
Peanut-free classrooms and lunch tables. A letter from your child’s teacher with snack ingredient restrictions. An Epi-Pen in the school nurse’s office. Twenty years ago these were rare occurrences but now they are commonplace. The increase in food allergy diagnosis over the last twenty years has been remarkable and has led to significant changes in individuals’ lives and society in general. So, what’s behind the rapid rise in allergies, how bad is it really, and is there anything we can do about it?
How big is the food allergy problem?
Most experts agree that food allergies are on the rise, but getting a precise number can be difficult. The CDC estimates that around 5% of kids have a food allergy, but studies have put that number from as high as 8% to just under 3%. That’s a pretty big spread, and it’s due mostly to differences in how we define food allergy and shortcomings in food allergy testing. Blood or skin testing alone tends to overestimate the number of food allergies by a wide margin. An oral challenge (meaning, what happens when someone eats the food) is a much better test, but is seldom utilized in general practice due to the risk involved. In one study, 12% of kids had a positive food allergy test, but only 3% reacted to the food on oral challenge. So, part of the rise in food allergy diagnosis is simply due to greater use of tests that aren’t very accurate. But that isn’t the whole story since we know that true food allergy is on the rise as well.
Why are food allergies increasing?
Like most problems in medicine, developing allergies comes from a combination of genetics and environment. Our genes haven’t changed appreciably in the last 20 years, so there must be some environmental factor(s) leading to the rise in food allergies. First, part of this can be explained by the “hygiene hypothesis,” which states that since our immune systems no longer encounter as many germs and parasites as we used to, they focus their attention on allergens instead. Personally, I think swapping polio for peanut allergy or rubella for ragweed allergy is a great deal. Second, it is now clear that we have done ourselves a huge disservice by trying to reduce food allergy through maternal and early childhood avoidance. The immune system has a window during gestation and early childhood where it is much more likely to learn to tolerate a substance than to learn to reject it. Studies now clearly show that eating foods like peanuts, milk and wheat throughout pregnancy and during early childhood reduces the risk for developing allergies to these foods.
What can we do about food allergies?
Once someone has developed a food allergy it is very difficult to treat, so most of our efforts focus on proper diagnosis, prevention, avoidance, and management of reactions. If you think you or your child has a food allergy, the first step is to be evaluated by a board-certified allergist. Proper test selection and interpretation is critical since many patients are incorrectly labeled as food-allergic. Next, expose yourself and your child to allergenic foods during pregnancy and early childhood. This will significantly reduce the risk of developing a food allergy. Third, if you or child has a confirmed food allergy, educate yourself. Food Allergy Research and Education (FARE) is an excellent source of credible, practical information on living with food allergies. Finally, people with food allergies must have access to injectable epinephrine and the knowledge of how and when to use it.
What are the most common food allergens?
Most common food allergens are: milk, eggs, wheat, soy, peanut, tree nuts, fish, shellfish and corn. Emerging allergens include sesame seeds.
What are the signs/symptoms of a food allergy?
Food allergies generally occur within minutes of ingestion. A typical reaction will start with some immediate oral symptoms, such as itching or irritation followed by, in order of severity, hives, lip/tongue swelling, facial swelling, trouble swallowing, trouble breathing and feeling lightheaded or dizzy. If symptoms are strictly cutaneous (i.e. related to the skin, like hives), then the reaction can be managed with simple antihistamines. Airway compromise from tongue or throat swelling, trouble breathing, and changes in the level of consciousness all constitute medical emergencies and are indications for immediate administration of epinephrine and activation of EMS.
Are there medicines we should have on hand in case of a cutaneous reaction?
Knowledge is power. Thank you, Dr. O.! For more information about allergies or Dr. Overholt’s practice, visit his website: www.allergymidtn.com.
Dr. Overholt is board certified in internal medicine and allergy and immunology. He is also a member of the Nashville Academy of Medicine, the Tennessee Medical Association and the American College of Allergy, Asthma & Immunology. He is a Fellow of the American Academy of Allergy, Asthma & Immunology and is a past President of the Tennessee Society of Allergy, Asthma & Immunology.