Eosinophilic Esophagitis: An Overlooked Entity in Chronic Dysphagia

Brian M. Yan and Eldon A. Shaffer

Disclosures

Nat Clin Pract Gastroenterol Hepatol. 2006;3(5):285-289. 

In This Article

Discussion of Diagnosis

Eosinophilic esophagitis was first reported in 1978[1] and has gained widespread recognition over the past 10 years.[2] Eosinophilic esophagitis is a disorder in which eosinophils infiltrate the superficial mucosa of the esophagus and are activated to release inflammatory mediators. It is best known in the pediatric population,[3] probably owing to more-aggressive investigations in children with gastrointestinal symptoms compared with investigations in adults, and the practice patterns of pediatric gastroenterologists who collect random gastrointestinal biopsies in all symptomatic cases. Population-based data from 2000-2003 in a pediatric population from Hamilton County, OH, US, suggest an annual incidence of 1 in 10,000.[3] Nonetheless, multiple case series are being described in the adult population;[4,5,6,7,8] large studies are lacking, but estimates suggest a frequency of 1 in 10,000.[4] The diagnosis is dependent on the patient's clinical presentation, endoscopic features, and histologic criteria, although no consensus has been reported to date.

Compared with other regions of the gastrointestinal tract, the esophagus normally lacks eosinophils. During an allergic response, tissue injury, or infection, eosinophils are major effector cells, releasing chemokines, lipid mediators, cytokines, and cytotoxic secretory products.[9,10] How eosinophils move to and accumulate in the esophagus in eosinophilic esophagitis has not been entirely elucidated; interleukin (IL)-5, eotaxins and IL-13 seem to have critical roles.[9,10]

Adults with eosinophilic esophagitis tend to be male, 30-40 years of age, with a long-standing history of solid-food dysphagia, some with food impaction.[5,6] Atopy, including asthma, atopic dermatitis, eczema, and food and seasonal allergies (such as hay fever), is also common. Gastroesophageal reflux disease (GERD), vomiting, and regurgitation might be present, whereas hematemesis and weight loss are uncommon in such patients. By contrast, children with eosinophilic esophagitis more often present with atopy, abdominal pain, and failure to thrive. The clinical presentation varies with age: toddlers might present with vomiting and feeding disorders; children with vomiting and abdominal pain; and older children and adolescents with symptoms similar to those seen in adult patients.[3,10,11,12] Whether pediatric eosinophilic esophagitis evolves into the adult variety is unclear.

The laboratory features of eosinophilic esophagitis are not well defined in published reports.[4,12] Peripheral eosinophilia might point toward a diagnosis of eosinophilic esophagitis, but is not seen in all patients. Elevated IgE levels might suggest an atopic disorder, but again are not sensitive or specific enough for diagnosing eosinophilic esophagitis. Skin testing for specific food allergies might help in the management of eosinophilic esophagitis, but has a minor role in its diagnosis.[13]

Endoscopic features of eosinophilic esophagitis have been well characterized.[2,3,4,5,6,7,8] These features might be quite overt (Figure 1), but more often are subtle, with less clear evidence of rings or corrugation in the proximal esophagus. Clinicians must, therefore, be aware of this disorder and its more subtle clinical features in order to make the correct diagnosis. The most common endoscopic findings in eosinophilic esophagitis, in order of frequency, are: mucosal rings (feline esophagus, 81%), vertical furrows (74%), strictures (31%), exudates (15%), small caliber (10%), and edema (8%).[7,8] The esophageal mucosa might also be fragile ('crêpe paper mucosa'), which could explain the frequency of esophageal tears following diagnostic endoscopy, biopsy, or dilatation for dysphagia associated with a narrowed esophagus or its ringed structure. The endoscopic appearance is helpful but not diagnostic without a confirmatory biopsy. Interestingly, 32% of a large cohort of children with eosinophilic esophagitis had a normal-appearing esophagus.[12]

Histology is critical to the diagnosis of eosinophilic esophagitis and should clearly show marked eosinophilic infiltration of the squamous epithelium.[9,10,14] In this patient, the entire esophagus, both proximally and distally, showed a diffuse eosinophilic infiltrate. Most studies suggest that >20 eosinophils per HPF in a single field or >15 eosinophils per HPF in two fields is diagnostic of eosinophilic esophagitis, although the density is usually higher, with a mean of 40 eosinophils per HPF.[2,9,10,14] Reflux esophagitis can produce an eosinophilic infiltration, although it is usually limited to the distal esophagus and is at a much lower density of <10 eosinophils per HPF.[6,7] To be secure in the diagnosis, mid-esophageal or upper-esophageal biopsies with increased eosinophils are more specific for eosinophilic esophagitis. Other helpful but not essential features for the diagnosis include basal-zone hyperplasia, increased papillary size, and a superficial layering of eosinophils with aggregates of four or more contiguous eosinophils (microabscesses),[14] many of which were evident in this patient (Figure 2).

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