ADVANCES Advances in our understanding of allergic reactions have led to exciting discoveries and new treatments. With earlier and better treatments, we may begin to dampen the impact of allergies on public health. However, as with all new treatments and information, we must consider the safety and larger public health impact of new discoveries and treatments. Below, we have highlighted a few of the many exciting advances as well as some of the potential public health implications.
Allergy Research in the News What is Eosinophilic Esophagitis? You may be familiar with the burning sensation associated with gastric acid reflux, commonly known as heartburn. As acid backs up into the esophagus (your food pipe) from the stomach, it causes inflammation and irritation, or esophagitis. This clinical condition may be common, but its lesser known cousin, eosinophilic esophagitis (EE), first described in the mid-1990s, is starting to gain press [1]. Eosinophilic esophagitis has little to do with gastric acid and is, instead, a reaction to commonly ingested allergenic foods. While this is not a classic anaphylactic-type reaction, it is a specific food-related reaction akin to an allergy. Those living with EE commonly experience food getting “stuck” in their chest and learn to eat small bites and drink excess water to “wash food down.” On the cellular level, tissue biopsies of these patients’ esophagi display an excess number of eosinophils (a specialized immune cell). The current proposed mechanism of disease suggests that food allergens trigger specific IgEindependent immune reactions in the
esophagus which result in recruitment of eosinophils to the esophagus wall (for more information on IgEdependant allergies, see the article “What is an Allergy?”). Continued inflammation and immune activation in the esophagus leads to chronic inflammation and a breakdown in the esophagus wall barrier leading to the symptoms described above [1]. Interestingly, these patients’ symptoms improve with specialized diets. When individuals eliminated the six most commonly allergenic foods (wheat, milk, soy, nuts, eggs, and seafood) from their diet, a large number of patients felt better, and their biopsies contain fewer eosinophils. If the patients resume eating trigger foods, however, they will relapse [1]. Approximately 56 out of 100,000 U.S. citizens are currently living with EE [2]. Some theorize that a change in our environmental exposures cleaner environments, less population crowding, and more C-sections - have led to an increase in prevalence [1]. That said, it is unclear if the true prevalence of EE is rising or if we are now more equipped to recognize the condition thus more people are being diagnosed. Whatever the root
cause may be, EE is a newly-described entity rooted in the concept of allergic reactions with a unique biochemical mechanism. References [1] Noel, Richard J., Philip E. Putnam, and Marc E. Rothenberg. "Eosinophilic esophagitis." New England Journal of Medicine351, no. 9 (2004): 940-941. [2] Dellon, Evan S., Elizabeth T. Jensen, Christopher F. Martin, Nicholas J. Shaheen, and Michael D. Kappelman. "Prevalence of eosinophilic esophagitis in the United States." Clinical Gastroenterology and Hepatology 12, no. 4 (2014): 589-596.
Illustration by Jennie Chen
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