The Esophageal String Test as a Diagnostic Screening Tool for Eosinophilic Esophagitis Among Africans With Dysphagia in Mali and the United States

* INCLUSION CRITERIA: In order to be eligible to participate in this study, an individual must meet all of the following criteria: 1. Able to provide informed consent. 2. Aged 18 to 65 years. 3. Born in the African continent or their parents were born in Africa, 4. Exhibiting symptoms of dysphagia and/or prior history of food impaction. 5. Undergoing clinically indicated endoscopy at the NIH Clinical Center (U.S.), Centre Hospitalier Universitaire Gabriel Tour(SqrRoot)(Copyright) (Mali), or other local clinics (Mali) and willing to provide research samples and data. EXCLUSION CRITERIA: An individual who meets any of the following criteria will be excluded from participation in this study: 1. Recent steroid use (systemic or swallowed/topical corticosteroid) within 4 weeks prior to endoscopy. 2. Recent use of dupilumab (Dupixent) within the last 6 months. 3. Recent use of other biologic medications (within either 6 months or 5 half-lives, whichever is longer). Examples of biologic medications include: 3a. mepolizumab (Nucala) 3b. reslizumab (Cinqair, Cinqaero) 3c. benralizumab (Fasenra) 3d. cendakimab 3e. tezepelumab (Tezspire) 3f. barzolvolimab 4\. Individuals suffering from a bleeding diathesis (e.g., hemophilia, severe thrombocytopenia). 5\. Current use of anticoagulant medications. 6\. Pregnancy. 7\. Treatment with another investigational drug or other investigational intervention within 6 months or 5 half-lives whichever is longer. 8\. Individuals with a known history of any of the following: 8a. eosinophilic esophagitis 8b. esophageal stricture unable to be passed with an upper endoscope 8c. esophageal cancer 8d. esophageal motility disorder (e.g., achalasia) 8e. esophageal varices 8f. esophageal or gastric surgery including fundoplication 8g. neurologic cause of dysphagia (e.g., stroke, Parkinson s disease, etc.) 8h. allergy to gelatin 8i. inability to swallow pills 9\. Any condition that, in the investigator s opinion, places the individual at undue risk by participating in the study. Co-enrollment guidelines: Co-enrollment in other trials is restricted, other than enrollment on observational studies. Consideration for co-enrollment in trials evaluating the use of a licensed medication will require the approval of the principal investigator in consultation with the medical monitor. Study staff should be notified of co-enrollment on any other protocol as it may require the approval of the principal investigator.