FYI for all reading this thread:
Eosinophilic esophagitis, a type of white blood cell (eosinophil) builds up in the tube that connects your mouth to your stomach (esophagus) as a reaction to foods, allergens or acid reflux. When that happens, the eosinophils can inflame or injure the esophageal tissue. A diagnosis of eosinophilic esophagitis is based in large part on a thorough review of your medical history and on your symptoms.
The following procedures to help diagnose eosinophilic esophagitis:
Upper endoscopy. A long narrow tube (endoscope) containing a light and tiny camera is inserted through your mouth down the esophagus. Your doctor inspects the lining of your esophagus for signs of eosinophilic esophagitis, such as inflammation, horizontal rings, vertical furrows, narrowing (strictures) and white spots.
Biopsy. During endoscopy, your doctor will remove a small tissue sample from the lining of your esophagus for laboratory analysis. The presence of a high number of eosinophils in the tissue confirms the diagnosis for eosinophilic esophagitis. Reference: Mayo Clinic Staff