Eosinophilic esophagitis (EoE) is an allergic inflammatory condition of the esophagus that involves eosinophils, a type of white blood cell. In healthy individuals, the esophagus is typically devoid of eosinophils. In EoE, eosinophils migrate to the esophagus in large numbers. When a trigger food is eaten, the eosinophils contribute to tissue damage and inflammation. Symptoms include swallowing difficulty, food impaction, vomiting, and heartburn.Eosinophilic esophagitis was first described in children but also occurs in adults. The condition is not well understood, but food allergy may play a significant role. The treatment may consist of removal of known or suspected triggers and medication to suppress the immune response. In severe cases, it may be necessary to enlarge the esophagus with an endoscopy procedure. While knowledge about EoE has been increasing rapidly, diagnosis of EoE can be challenging because the symptoms and histo-pathologic findings are not specific. Epidemiology
The prevalence of eosinophilic esophagitis has increased over time and currently ranges from 1 to 6 per 10,000 persons. Gender and ethnic variations exist in the prevalence of EoE, with the majority of cases reported in Caucasian males.In addition to gender (male predominance) and race (mainly a disease of Caucasian individuals), established risk factors for EoE include atopy and other allergic conditions. Other recognized genetic and environmental risk factors for EoE include alterations in gut barrier function (e.g. GERD), variation in the nature and timing of oral antigen exposure, lack of early exposure to microbes, and an altered microbiome.
Due to the long-standing inflammation and possible resultant scarring that may have gone unrecognized, adults presenting with EoE tend to have more episodes of esophageal food impaction as well as other esophageal abnormalities such as Schatzki ring, esophageal webs, and in some cases, achalasia.Although many of these symptoms overlap with the symptoms of GERD, the majority of patients with EoE exhibit a poor response to acid-suppression therapy. Many people with EoE have other autoimmune and allergic diseases such as asthma and celiac disease. Mast cell disorders such as Mast Cell Activation Syndrome or Mastocytosis are also frequently associated with it. Pathophysiology
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. Eosinophils are normally present in other parts of a healthy gastrointestinal tract, these white blood cells are not normally found in the esophagus of a healthy individual. The reason for the migration of eosinophils to the tissue of the esophagus is not fully understood but is being studied extensively. It is thought the migration of eosinophils to the esophagus may be due to genetic, environmental, and host immune system factors.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.