Etiology of Eosinophilic Esophagitis

Population studies show a steady rise in the incidence (6.6 per 100,000 person-years) and prevalence (34 per 100,000) of Eosinophilic Esophagitis (EoE) in children. These figures are consistent between US and European studies. EoE is more common in boys than girls (3:1).

The etiology of EoE is not completely understood, but like other atopic diseases, it appears to result from an interplay between genetics and environment.

Pathologic and Genetic Factors

Altered epithelium in the esophagus is implicated in the symptoms of EoE. A healthy esophagus maintains a balance of epithelial proteases and protease inhibitors that protect the tissues from food-borne enzymes. The disruption of this balance by environmental and genetic factors is a likely trigger for the characteristic inflammatory response to foods and aeroallergens.

Research shows that epithelial cells in patients with EoE have significantly altered transcription patterns and that at least one protein, SPINK7, is nearly absent in the esophageal biopsy samples of patients with EoE.

Monozygotic twins have 41% disease concordance and dizygotic twins have 24% concordance. However, the risk of EoE in siblings of a child with the disease is 2.4%. These data indicate a complex interplay between genetic predisposition and the development of disease.

Environmental Factors

The marked increase in the diagnosis of EoE along with data from twin studies indicate that environmental factors likely play a large role in the etiology of EoE.

Environmental factors that are reliably associated with EoE include:

• Food allergens – Milk is the most common food trigger of EoE (followed by wheat, egg, and soy)
• Aeroallergens – Many patients with EoE have co-morbid atopic conditions such as allergic rhinitis. The interplay between direct exposure to aeroallergens and development or exacerbations of EoE is complex and variable.
• Antibiotics in infancy – Similar to observational studies for other atopic conditions, antibiotic use in infancy is correlated with a higher risk of EoE, but causality has not been established.

Other possible associations that have been implicated in a limited number of studies or are not conclusively linked because of conflicting data, include:

• Prenatal factors (preterm labor, maternal fever)
• Lack of breastfeeding
• NICU admission
• Cesarean delivery
• Proton pump inhibitor use
• Exposure to pets in the home during infancy
• Rural home environment

EOE Buying

The development of this information was made possible through support from Sanofi Genzyme and Regeneron.