Eosinophilic esophagitis is caused by the presence of a large number of eosinophils in the esophagus. The production and accumulation of eosinophils may be caused by many factors such as immune hypersensitivity responses to particular foods or environmental proteins (allergens) in some affected individuals. Some individuals with this condition have been found to have an unusually high expression of a particular gene called eotaxin-3. This gene codes for a protein that is important in controlling the accumulation of eosinophils. Eosinophilic esophagitis can run in families but the risk for additional families members is <5% unless they are twins with the EoE patient. Several genes have been identified to contribute to EoE including CAPN14 (at chromosome 2p23) and TSLP (at chromosome 5q22).

Related Disorders
Symptoms of the following disorders are similar to those of eosinophilic esophagitis. Comparisons may be useful for a differential diagnosis:

Gastroesophageal reflux disease (GERD) is a digestive disorder characterized by reflux of the contents of the stomach or small intestines into the esophagus. Symptoms of gastroesophageal reflux may include a sensation of warmth or burning rising up to the neck area (heartburn or pyrosis), swallowing difficulties (dysphagia), and chest pain. This condition is a common problem and may be a symptom of other gastrointestinal disorders.

Ulcerative colitis is an inflammatory bowel disease (IBD) of unknown cause. It is characterized by chronic inflammation and ulceration of the lining of the major portion of the large intestine (colon). In most affected individuals, the lowest region of the large intestine, known as the rectum, is initially affected. As the disease progresses, some or the entire colon may become involved. Although associated symptoms and findings usually become apparent during adolescence or young adulthood, some individuals may experience an initial episode between 50 and 70 years of age. In other cases, symptoms may occur as early as the first year of life. (For more information about this condition, choose "colitis" as your search term in the Rare Disease Database.)

Crohn’s disease is an inflammatory bowel disease characterized by severe, chronic inflammation of the intestinal wall or any portion of the gastrointestinal tract. The lower portion of the small intestine (ileum) and the rectum are most commonly affected by this disorder, but the esophagus can also be involved. Symptoms may include watery diarrhea, abdominal pain, fever, and weight loss. The exact cause of Crohn’s disease is unknown.