The most common method to distinguish EE from reflux disease is to perform an upper endoscopy (also known as esophagoduodenoscopy (EGD) or upper GI) after a patient has been on a PPI (Proton-Pump Inhibitor such as omeprazole, esomeprazole, lansoprazole) for an established period (generally at least a few months’ time). Appropriate medications and dosing should be discussed with the gastroenterologist who is performing the endoscopy. It is important to note that H2 blockers such as ranitidine or cimetidine may not effectively reduce acid production so treatment with this class of medicines may result in persistent eosinophilic inflammation in the esophagus. While on effective acid-blockade therapy, biopsies should be taken to evaluate for eosinophilia. It is advisable to have 3 or more esophageal biopsies taken during the procedure since EE can sporadically involve the esophagus so the diagnosis may be missed if only 1 or 2 biopsies are taken. Even if the appearance of the esophagus looks normal to the eye, biopsies should be taken since significant eosinophilic inflammation can be seen in these areas.
In addition, the esophagus may have some visual changes that can support the diagnosis of EE. Often, a pale color or pallor to the esophageal tissue is present. Another common findings are white specks or flecks noted on the esophageal mucosa which represent eosinophilic microabscesses. In additional creases or furrowing along the length of the esophagus can be seen. A less common finding is circumferential creasing can occur described as a feline esophagus or trachealization (referring to the resemblance of the trachea. Extensive narrowing, that is esophageal strictures, can also be observed usually from longstanding inflammation which results in the difficulty swallowing that is often seen in EE. Finally, as mentioned above the esophagus can look normal in a patient with eosinophilic esophagitis. And conversely, reflux disease can result in similar appearances, so the biopsies become central in confirming or ruling out the diagnosis of EE.