A dramatic rise in the recognition of eosinophilic esophagitis (EoE) has followed the case series by, and , which first characterized the disease 25 years ago. While still a young disease, EoE has evolved from esoterica to a leading cause of dysphagia and food impaction worldwide ( ). The typical face of EoE is a 30- to 40-year-old white man, but EoE afflicts both men and women of all ages and ethnic groups.
Guidelines prior to 2017 excluded proton pump inhibitor–responsive esophageal eosinophilia (PPIREE) from a formal diagnosis of EoE. The last decade, however, has witnessed the rise of fall of PPIREE, which was first reported in 2006 in a case series of three pediatric patients with presentations consistent with EoE, but symptom and histologic resolution after treatment with omeprazole. At the time, these cases were viewed as rare curiosities. Subsequent to aby , in 2011, however, multiple studies have demonstrated that 30%-50% of patients suspected of having EoE respond to proton pump inhibitor (PPI). Clearly, PPIREE is not rare. Clinical and translational studies have investigated the phenomenon of PPIREE, noting that EoE and PPIREE share demographic, symptom, endoscopic, and pathologic features as well as biomarker expression and gene profiles that are distinct from gastroesophageal reflux disease (GERD). Furthermore, studies have identified intriguing, acid-independent properties of PPIs that inhibit allergic inflammation in cultured EoE cell lines. Together, these clinical and translational studies led to a 2016 European task force recommendation to remove the PPI trial from the diagnostic criteria for EoE ( ). At Digestive Disease Week 2017®, an international consortium sponsored by the International Gastrointestinal Eosinophil Researchers (TIGERS) convened in Chicago to review this controversy. The consensus from this meeting was in line with the European position statement. For patients with a clinical presentation suggestive of EoE and esophageal eosinophilia, clinicians should carefully consider non-EoE causes of esophageal eosinophilia but would not be required to use PPIs to establish a diagnosis of EoE.
Assessment of disease activity in EoE has largely focused on counting eosinophils on esophageal biopsies, but the mucosa may be the tip of the EoE iceberg. There is increasing evidence that the inflammation and remodeling aspects of EoE extend beneath the mucosa. If you “dig a little deeper” and sample the subepithelial space, a different face of EoE emerges, with eosinophilic inflammation and fibrosis in EoE that are distinct from GERD. This subepithelial remodeling forms the basis for the strictures and narrow caliber esophagus that are major complications of EoE.
Treatment of EoE involves a multifaceted approach that includes medications, dietary therapy, and esophageal dilation. No drugs have yet been approved by the Food and Drug Administration for EoE. Off-label use of topical corticosteroids are a mainstay of therapy, with 10 double-blind, placebo-controlled randomized trials demonstrating efficacy for both histology and symptoms. Novel therapeutic approaches to EoE are targeting allergic cytokine mediators including interleukin-4, 5, and 13 with promising results. The role of biologic therapies in the management of EoE is yet undefined but the increasing recognition of steroid-refractory patients as well as potential effects on esophageal remodeling are unmet needs. Diet therapy continues to be an important, first-line option for motivated patients and clinicians, with removal of the six most common food allergens associated with a 70% histologic response in both pediatric and adult studies. Less-restrictive diets have been devised to reduce the need for repeated endoscopies. At the same time, several office-based tests of disease activity are undergoing validation, including the esophageal string test,, mucosal impedance, transnasal endoscopy, and confocal microscopy capsule. These technologies will lead to fewer endoscopies and may shift EoE management to the primary care or allergist’s office.
Finally, it is important to acknowledge that EoE is not a “GI disease,” but one that is best managed by a multifaceted approach that integrates allergists, immunologists, pathologists, radiologists, dietitians, patient advocacy, and epidemiologists who are confronting this new disease. The Consortium of Eosinophilic Gastrointestinal Disease Researchers, funded by the National Institutes of Health and the Rare Diseases Clinical Research Network, is an example of a multidisciplinary collaboration that addresses fundamental questions regarding the natural history and optimal management of EoE.
Dr. Hirano is a professor of medicine, division of gastroenterology, Northwestern University, Chicago. He has received grant support from the NIH Consortium of Eosinophilic Gastrointestinal Disease Researchers (). CEGIR is also supported by patient advocacy groups including the American Partnership for Eosinophilic Disorders, the CURED Foundation, and the Eosinophilic Family Coalition. Dr. Hirano has received consulting fees and research funding from Celgene, Regeneron, and Shire among others. Dr. Hirano made his comments during the AGA Institute Presidential Plenary at the Annual Digestive Disease Week.