Clinical manifestations and diagnosis of eosinophilic esophagitis

INTRODUCTION

Esophageal eosinophils are considered to be a hallmark of gastroesophageal reflux disease (GERD) [1]. However, it is becoming increasingly apparent that the esophagus, (normally devoid of eosinophils) is an immunologically active organ which, similar to the colon, is capable of recruiting eosinophils in response to a variety of stimuli [2,3]. In addition to GERD, esophageal eosinophils have been described with a variety of other disorders (see below) [4-6].

One of these disorders, variably referred to as eosinophilic esophagitis or allergic esophagitis, is characterized by eosinophilic infiltration of the esophagus presumably due to allergic or idiopathic causes [7]. This entity has been described in children and adults with dysphagia either alone or as a manifestation of eosinophilic gastroenteritis. In its isolated form, it is an increasingly recognized cause of dysphagia and possibly heartburn that is unresponsive to antireflux measures.

This topic review will provide an overview of the clinical manifestations and diagnosis of eosinophilic esophagitis in adults and children. This subject is also discussed in guidelines issued by the American Gastroenterological Association [8]. The AGA guideline for the evaluation of food allergies [9], as well as other AGA guidelines, can be accessed through the AGA web site at www.gastro.org/wmspage.cfm?parm1=4453. Treatment of eosinophilic esophagitis is presented separately. (See "Treatment of eosinophilic esophagitis".)

EPIDEMIOLOGY

The epidemiology of eosinophilic esophagitis has not been extensively studied. It has been reported in several countries including Chile, Denmark, Sweden, Belgium, Greece, France, Spain, Portugal, Germany, Switzerland, Japan, China, England, Italy, the Netherlands, New Zealand, Australia, and the United States. There have been no published reports from countries in Africa. Whether there are geographic areas in which it does not occur is unknown; such a finding might help provide a clue as to its cause [10]. A pathology database study from the United States found that the disease had been detected in most states that reported data [11].

Eosinophilic esophagitis appears to have an accelerating incidence that cannot be fully accounted for by increased recognition [12,13]. The first cases appear to have been reported in the late 1960s to 1970s [14-16]. Increasing recognition is unlikely to fully account for the rising incidence; gastrointestinal barium radiography has been practiced for many decades and thus it is likely that the characteristic ringed pattern in the esophagus would have been described (Schatzki's ring, for example, was reported in 1953 [17]). Furthermore, as described further below, population-based studies have supported an increasing incidence not explained by increased recognition.