Eosinophilic esophagitis

What is eosinophilic esophagitis?

Eosinophilic esophagitis is a medical condition that develops when specialized immune cells called eosinophils damage the epithelium, the tissue barrier that covers the inside of the esophagus. Patients with eosinophilic esophagitis may experience difficultly swallowing food (especially hard food), throat and chest pain, and the sensation that food is stuck in their esophagus after swallowing. If left untreated, eosinophilic esophagitis may cause the esophagus to narrow, which can make it difficult to eat solid foods.

The esophagus

The esophagus is a long hollow tube that starts at the back of your throat and ends at the top of your stomach. When you swallow food or liquids they travel down the esophagus into the stomach. The inner surface of the esophagus is lined with specialized squamous cells that form a barrier to protect the inside of the esophagus. This thin tissue barrier is called the epithelium.

normal esophagus histology

How do pathologists make this diagnosis?

In order to make a diagnosis of eosinophilic esophagitis, multiple tissue samples must be taken from the inside of the esophagus. These tissue samples are called biopsies. Your doctor will use a camera device called an endoscope to examine the inside of your esophagus and to perform the biopsies. This is a brief procedure that may cause some discomfort but is not painful. Your pathologist then examines the tissue samples under a microscope.

Eosinophilic esophagitis does not always affect the entire esophagus equally, and as a result, biopsies should be taken from the beginning, middle, and end of the esophagus. Pathologists use the term, “proximal”, to describe the beginning of the esophagus and the term, “distal”, to describe the end.

eosinophilic esophagitis

When examined under the microscope, the tissue samples from a person with eosinophilic esophagitis will show a large number of eosinophils within the epithelium. Pathologists describe this condition as intraepithelial eosinophils. Small groups of eosinophils called microabscesses may also be seen. There may also be an increase in the number of cells that sit at the very bottom of the epithelium. These cells are called basal cells and pathologists describe this change as basal cell hyperplasia.

What causes eosinophilic esophagitis?

Eosinophilic esophagitis is thought to be caused by an allergic reaction to food. The reaction takes place as the food travels down the esophagus towards the stomach.

Who is at risk for developing eosinophilic esophagitis?

Eosinophilic esophagitis is more common in people who have a history of non-food allergies and asthma. It is also more common in people who have a parent or sibling with the condition.

Long-standing gastroesophageal reflux disease (GERD) is also associated with an increased risk of developing eosinophilic esophagitis, possibly because the damage caused to the inside of the esophagus allows food allergens to bypass the epithelium and enter the body.

by Jason Wasserman MD PhD FRCPC (updated July 10, 2021)
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