Confocal laser endomicroscopy enables in vivo microscopic imaging within the mucosa layer of the gut at a subcellular resolution. Various studies have addressed the potential of endomicroscopy for the in vivo diagnosis of esophageal squamous cell carcinoma, Barrett´s esophagus and esophageal adenocarcinoma. Currently, there is only one case report from our group who noted the utility of endomicroscopy for the in vivo diagnosis of eosinophilic esophagitis.

The purpose of this study is to determine whether endomicroscopy is effective for the in vivo diagnosis of eosinophilic esophagitis.

Inclusion Criteria:

• Written informed consent
• Age 18-85 years
• Ability of subjects to understand character and individual consequences of clinical trial
• Subjects undergoing EGD

Exclusion Criteria:

• Inability to provide written informed consent
• Severe Coagulopathy (Prothrombin time < 50% of control, Partial thromboplastin time > 50 s)
• Impaired renal function (Creatinine > 1.2 mg/dl)
• Pregnancy or breast feeding
• Active gastrointestinal bleeding
• Known allergy to fluorescein, acriflavin or cresyl violet
• Residing in institutions (e.g. prison)

Patients with eosinophilic esophagitis who underwent EGD for the evaluation of their symptoms.

Control patients who underwent EGD because of other reasons.