[Eosinophilic esophagitis: an "emerging disease"]

Eosinophilic esophagitis is a recently identified disease. The histological examination of esophageal biopsies is essential for its diagnosis, which is made with steadily increasing frequency. Eosinophilic esophagitis is an anatomoclinical entity, involving both children and adults, characterized by a dense and isolated infiltration of the esophageal mucosa by eosinophils, revealed by clinical symptoms of upper digestive tract origin and resistant to anti-acid treatment with IPP at high doses. Eosinophilic esophagitis is currently interpreted as an allergic disease, even though its pathogenesis remains unclear. The disease has a chronic course with persistent or relapsing symptoms, present with symptoms similar to those of gastro-esophageal reflux or with dysphagia. Endoscopic examination shows the presence of characteristic, but not pathognomonic, lesions (stenoses, strictures, circular rings, reduction of calibre, white specks, granularity of the mucosa). The histological diagnosis requires multiple biopsies taken all along the esophagus. The main sign is the presence of a dense eosinophilic infiltrate of the mucosa: a peak density of more than 15 eosinophils in at least one x400 field is the minimal criteria required for diagnosis. Associated lesions correspond to tissue damage and repair secondary to eosinophil activation (basal hyperplasia, microabscesses, fibrosis of the lamina propria). The treatment is based on dietary measures (allergen exclusion) and on the use of anti-inflammatory drugs, mainly corticoids. In conclusion, eosinophilic esophagitis is an emerging disease, important to identify, since it requires a specific treatment, different from that of reflux esophagitis.