Date Published: November 10, 2011
Publisher: BioMed Central
Author(s): Stuart Carr, Wade Watson.
Eosinophilic esophagitis (EoE) is an atopic condition of the esophagus that has become increasingly recognized over the last decade. Diagnosis of the disorder is dependent on the patient’s clinical manifestations and histologic findings on esophageal mucosal biopsies. Patients with eosinophilic esophagitis should be referred to both an allergist and gastroenterologist for optimal management, which may include dietary modifications, pharmacologic agents such as corticosteroids, leukotriene modifiers and biologics as well as mechanical dilatation of the esophagus. The epidemiology, pathophysiology, diagnosis, treatment, and prognosis of EoE are discussed in this review.
Eosinophilic esophagitis (EoE) is an atopic inflammatory disease of the esophagus that has become increasingly recognized in children and adults over the last decade. The disorder is sometimes referred to as “asthma of the esophagus” given that it shares many clinical and pathophysiologic characteristics with asthma .
Given the poor awareness and recognition of the disease in the past, the epidemiology of EoE is still unclear. In children/adolescents up to 19 years of age, current prevalence estimates range from 1 to 4 per 10,000 persons . Recent literature suggests that the prevalence of EoE is increasing . However, there is debate as to whether the new cases of EoE being diagnosed represent a true increase in prevalence or rather increased recognition of latent disease. Furthermore, esophageal endoscopic biopsies are currently required to establish the diagnosis of EoE and, therefore, variations in endoscopy practices may bias the results of epidemiologic studies. For example, some studies suggest that when correcting for the number of endoscopies/biopsies being performed, the perceived increase in the prevalence of EoE may not be as dramatic as originally postulated .
Although the pathogenesis of EoE remains unclear, evidence suggests that the disease is associated with T helper cell (Th)-2 type immune responses, which are typical of other atopic conditions. In particular, elevated levels of the Th2 cytokines interleukin (IL)-4, IL-5, and IL-13, as well as mast cells, have been found in the esophagus of EoE patients [8-10]. These cytokines appear to play an important role in the activation and recruitment of eosinophils to the esophagus. Furthermore, there is evidence suggesting a genetic predisposition for the disease since the gene for eotaxin-3 – a chemokine involved in promoting eosinophil accumulation and adhesion – has been found to be overexpressed in patients with EoE .
Since the physical examination of patients with EoE is often unrevealing, the diagnosis of EoE is dependent on the patient’s clinical manifestations, endoscopic assessment of the esophagus and histologic findings on esophageal mucosal biopsies.
Treatment strategies available for EoE fall into three categories: (1) avoidance of triggers through dietary modification, (2) pharmacologic therapy (corticosteroids, leukotriene modifiers and biologics), and (3) mechanical dilatation of the esophagus. It is important to note, however, that most of the published studies examining these therapies are case series, and there has been limited testing of these regimens in randomized controlled trials.
The long-term prognosis for patients with EoE is unknown. Some patients may follow a “waxing and waning” course characterized by symptomatic episodes followed by periods of remission. There have also been reports of apparent, spontaneous disease remission in some patients; however, the risk of recurrence in these patients is unknown. It is possible that long-standing, untreated disease may result in esophageal remodeling, leading to strictures, Schatzki ring and, eventually, achalasia. Currently, it is still unclear if dietary or medical therapy modifies the natural history of the disease .
EoE is an evolving condition that requires further study to better understand the mechanisms of disease development and tissue injury, the natural history, and optimal management. Although clearly an atopic condition, the role of specific allergic triggers in EoE remains unclear. However, as our understanding surrounding EoE improves, so will strategies for the diagnosis and treatment of the condition.
• EoE is an atopic condition of the esophagus that has become increasingly recognized over the last decade.
Dr. Stuart Carr has received consulting fees and honoraria for continuing education from GlaxoSmithKline, Graceway, Merck, Novartis, Nycomed, and Paladin. He is a local principal investigator for a Ception-sponsored study of reslizumab, a novel biological therapeutic agent for eosinophilic esophagitis. Dr. Carr did not receive any incentive or funding for the preparation or review of the manuscript.