Eosinophilic esophagitis is a chronic, antigen-driven, immune-mediated disease of the esophagus. It is defined clinically by symptoms of esophageal dysfunction and, histologically, by eosinophil-dominant inflammation.
Classification
Eosinophil-associated esophageal disorders fall into two groups. Primary eosinophilic esophagitis is the disease itself; it can be atopic or non-atopic, and it can appear as part of a syndrome such as EoE associated with connective tissue disease, or in a familial form. Secondary esophageal eosinophilia has another underlying cause, such as a systemic hypereosinophilic syndrome, or reflects a disorder that is not primarily eosinophilic.
EoE clusters in families. Around 2% of first-degree relatives of an affected person also have EoE, and the recurrence risk in relatives is raised roughly 10- to 64-fold, highest in brothers. The pattern is consistent with complex, non-Mendelian inheritance rather than a single gene.
Recognition and incidence
EoE came to attention when eosinophilic inflammation was found in patients with gastroesophageal reflux disease (GERD) that did not respond to proton pump inhibitors; about 10% of such patients showed this finding. The annual incidence of EoE in different population studies is reported to be between 0.1 and 1.2 in 10,000 of population.
Pathophysiology
The exact pathophysiology of EoE is not fully worked out, but several strands of evidence point the same way: it rests on an allergic (atopic) base, it tracks with other allergic diseases such as seasonal rhinitis and asthma, and the chemokine eotaxin-3 is over-expressed in the esophageal epithelium.
Symptoms
The presenting symptom changes with the age of the patient. Infants and toddlers have difficulty feeding; school-age children have vomiting and pain; adolescents develop dysphagia (difficulty swallowing), and food may impact and fail to pass to the stomach. Failure to thrive, and chest or abdominal pain, also occur. The symptoms tend to follow a chronological order, shifting from vomiting towards dysphagia during the transition from school age to adolescence.
EoE in children is mostly accompanied by signs and symptoms of allergic reactions in other organs, such as asthma and rhinitis. When food impacts, endoscopic removal is needed in about 36% to 55% of cases, especially in adults.
Endoscopic findings
Endoscopy in EoE may show fixed or transient esophageal rings, whitish exudates, longitudinal furrows, edema, diffuse esophageal narrowing, and mucosal fragility, which is an esophageal laceration produced by the passage of the endoscope because the esophagus has lost its normal distensibility.