Eosinophilic esophagitis (EoE) is a chronic-inflammatory disease of the esophagus. If left untreated, eosinophilic inflammation induces fibrosis, angiogenesis and stricture formation, finally resulting in a so called remodelling with structural and functional damage of the organ. In addition, patients with untreated EoE are permanently at risk of experiencing food impactions. It is therefore widely accepted that active EoE should be recognized and treated as such. Any treatment applied in EoE should ideally achieve two therapeutic goals: first, resolution of symptoms, and, second, control of inflammation.~However, in some cases of EoE, there is a dissociation between symptoms and histological response.~Furthermore, characteristic endoscopic findings may occur together but are not all seen in every EoE patient. As an example, in 7% to 10% of cases the esophagus may appear normal. Lastly, inflammatory infiltration of the esophageal wall may be discontinuous. In order to define endoscopic activity of EoE in a standardized fashion, the endoscopic reference score (EREFS) is usually applied.~Several endoscopic ﬁndings, including linear furrows, concentric rings, white exudates, decreased vasculature in the esophageal mucosa, esophageal strictures, and the esophagus of narrow caliber have been reported to be the characteristic ﬁndings of EoE, although neither of these is speciﬁc. According to a meta-analysis from 2012, consisting primarily of retrospective studies involving adult cohorts, the overall pooled prevalence of endoscopic ﬁndings in patients with EoE was 44% rings, 21% strictures, 9% narrow caliber esophagus, 48% linear furrows, 27% white exudates, and 41% decreased vascularity, with a wide variation in the prevalence of those endoscopic ﬁndings between each report.~Lastly, inflammatory infiltration of the esophageal wall may be discontinuous. Taken together, endoscopic recognition of EoE remains a major clinical challenge and diagnosis still relies on histological sampling which in turn renders the diagnosis prone to sampling errors.~In addition to that, it is well known that optimal control of inflammatory activity is crucial in order to prevent progression of fibrosis. Therefore, monitoring inflammatory activity (determined by the EoE histologic scoring system; EoE-HSS) is part of clinical routine in patients with EoE. As outlined above, endoscopic assessment, however, does not reliably reflect the underlying process of the disease during the index endoscopy and cannot be regarded as reliable follow-up test.~The investigators hypothesize that novel endoscopic technologies overcome the shortcomings of the standard endoscopic imaging. It is therefore planned to compare images of the esophageal mucosa using the EG-760Z endoscope by Fujifilm (Fujifilm Europe, Düsseldorf, Germany) to standard imaging with high magnification imaging. This novel endoscope acquires images with a magnification by a factor of 135. As gold standard, histological assessment of the inflammatory activity will be used.
In this study, we plan to investigate the accuracy of the EG-760Z endoscope (135x zoom) compared with standard imaging with histology as gold standard in detecting and grading inflammatory activity in patients with eosinophilic esophagitis (EoE).