Eosinophilic esophagitis is a chronic and increasingly recognized inflammatory disorder of the esophagitis characterized by abnormal infiltration of eosinophils of the esophageal mucosa, often resulting in dysphagia and food impaction. The disorder is being diagnosed with much greater frequency, and increased recognition, by virtue of increased endoscopic volume, alone may not be responsible for this trend. Studies have indicated that the incidence has increased more than fourfold in the last 5–10 years. More than 80% of patients diagnosed with eosinophilic esophagitis complain of dysphagia, and between 5% and 16% of patients undergoing endoscopic evaluation for dysphagia are found to have eosinophilic esophagitis. Further, more than 50% of patients presenting with frank food impaction are diagnosed with eosinophilic esophagitis. By contrast, in children and adolescents, gastroesophageal reflux disease (GERD) and esophageal reflux symptoms are as common as food impaction and dysphagia.

Eosinophilic esophagitis occurs in both the pediatric age group and adults. About 70–75% of the patients are male, and the commonest age of presentation is in the 20s and 30s. In older series the mean age at diagnosis was 34 years. In addition, in the older literature, symptom duration prior to diagnosis averaged 4.5 years. For reasons that are not clear the disease is more common in Caucasians. The incidence appears to be increasing and this is not only due to increased recognition of the disorder as a consequence of increased endoscopic volume, but perhaps due to other factors as well. This is evidenced by a population-based study that documented incidence of eosinophilic esophagitis in Olmsted County, Minnesota, where the incidence was 9.5 per 100,000 patients per year, and the prevalence 55 patients per 100,000. Similar population-based studies in Switzerland have also concluded that the incidence of eosinophilic esophagitis is increasing and may actually be approaching that of inflammatory bowel disease.

The pathogenesis of eosinophilic esophagitis is incompletely defined. However, considerable evidence suggests that eosinophilic esophagitis is an allergic disorder induced by antigen sensitization either through foods and/or aeroallergens.

A majority of patients have evidence of food allergies and a concurrent history of respiratory allergies. A seasonal variation has been documented in the diagnosis of eosinophilic esophagitis that correlated with pollen counts. By contrast, food anaphylaxis is uncommon, occurring in less than 15% of pediatric patients with eosinophilic esophagitis.

The recruitment of eosinophils occurs in several inflammatory or infectious conditions and after exposure to inhaled or ingested allergens. Eosinophils also release chemoattractants, such as interleukins, which can perpetuate an inflammatory response. The latter phenomenon has led to trials of leukotriene inhibitors in the treatment of eosinophilic esophagitis.

A. Symptoms and Signs

The leading symptom in adults is recurrent attacks of dysphagia. Mean duration of symptoms before diagnosis and initiation of treatment in one large series was 4.6 years. Recurrent dysphagia is present in the majority of patients, as is the history of food impaction. A personal history of allergic diseases (ie, airway, food, or skin allergies) is frequently present. Serum immunoglobulin E (IgE) elevations have been documented in one series in two-thirds of the patients. However, it should be emphasized that there is no difference in symptoms, endoscopic findings, or histology in patients with increased serum IgE levels versus those with normal IgE levels. Symptoms appear to be more pronounced in patients with peripheral blood eosinophilia. Another clinical feature is the presence of symptoms of GERD, dyspepsia, and xiphisternal and retrosternal discomfort that are seemingly refractory to medical management. In children and adolescents, symptoms include vomiting, regurgitation, GERD symptoms not responding to medical management, upper abdominal pain, and food impaction in the esophagus.

B. Endoscopy

Endoscopic features associated with eosinophilic esophagitis are highly variable. The esophageal mucosa may actually appear to be normal. Other more frequent findings include trachea-like circular rings that can be transient or fixed, white exudates, white nodules with granularity, linear furrowing, and vertical lines on the esophageal mucosa. In addition, the passage of the endoscope may lead to trauma. Finally, strictures in the proximal, middle, or distal esophagitis are sometimes encountered. Examples of typical endoscopic findings in eosinophilic eosinophils are shown in Plates 18 and 19.

Other disorders also may be associated with increased eosinophilic infiltration of the esophagus (see later). Accordingly, biopsies should be taken in both the distal and mid-esophagus in patients with suspected eosinophilic esophagitis. Characteristic histologic findings in eosinophilic esophagitis are shown in Plate 20.