EoE is a relatively poorly understood disease, although awareness of it is rising. At a tissue level, EoE is characterized by a dense infiltrate with white blood cells of the eosinophil type into the epithelial lining of the esophagus. This is thought to be an allergic reaction against ingested food, based on the important role eosinophils play in allergic reactions. Eosinophils are inflammatory cells that release a variety of chemical signals which inflame the surrounding esophageal tissue. This results in the signs and symptoms of pain, visible redness on endoscopy, and a natural history that may include stricturing.
Diagnosis
The diagnosis of EoE is typically made on the combination of symptoms and findings on diagnostic testing. Prior to the development of the EE Diagnostic Panel, EoE could only be diagnosed if gastroesophageal reflux did not respond to a six-week trial of twice-a-day high-dose proton-pump inhibitors or if a negative ambulatory pH study ruled out gastroesophageal reflux disease. Endoscopically, ridges, furrows, or rings may be seen in the esophageal wall. Sometimes, multiple rings may occur in the esophagus, leading to the term "corrugated esophagus" or "feline esophagus" due to similarity of the rings to the cat esophagus. Presence of white exudates in esophagus is also suggestive of the diagnosis. On biopsy taken at the time of endoscopy, numerous eosinophils can be seen in the superficial epithelium. A minimum of 15 eosinophils per high-power field are required to make the diagnosis. Eosinophilic inflammation is not limited to the esophagus alone, and does extend through the whole gastrointestinal tract. Profoundly degranulated eosinophils may also be present, as may microabcesses and an expansion of the basal layer. Radiologically, the term "ringed esophagus" has been used for the appearance of eosinophilic esophagitis on barium swallow studies to contrast with the appearance of transient transverse folds sometimes seen with esophageal reflux.
Treatment
Treatment strategies may include medication, dietary modification to exclude food allergens, and mechanical dilatation of the esophagus. Dietary treatment can be effective, as there does appear to be a role of allergy in the development of EOE. Allergy testing is not particularly effective in predicting which foods are driving the disease process. Various approaches have been tried, where either six food groups, four groups or two groups are excluded for a period of time, usually six weeks. Endoscopy is required to measure the response to the dietary measure. A "top down" approach may be very restrictive. Four- or even two-group exclusion diets may be less difficult to follow and reduce the need for many endoscopies if the response to the limited restriction is good. Endoscopic dilatation is sometimes required if there is significant narrowing of the esophagus. This is effective in 84% of people who require this procedure.
