BACKGROUND: Gastroesophageal reflux (GER) and eosinophilic esophagitis (EoE) are the two most commonly encountered esophageal diseases. While guidelines and clinical practice have generally considered them to be two distinct conditions with their own diagnostic criteria, both incorporate acid mediated breakdown in the esophageal epithelial barrier. The contribution of acid reflux to the pathogenesis of EoE has evolved over time. While published guidelines and multiple articles have emphasized the distinguishing features defining each, there exist clinical instances in which the two have overlapping features. CASE DESCRIPTION: An adolescent patient is described with clinical and epidemiological features associated with both GER (hiatal hernia, distal esophageal erosions, and a family history of significant GER) and EoE (a strong history of atopy, and endoscopic and histologic findings specific to EoE). At different times, he had endoscopic and histologic features that would satisfy the criteria for each of these two entities. CONCLUSIONS: While acid injury is the defining characteristic of GER, it also often plays a role in EoE, as reflected in the recognition of proton pump inhibitor responsive esophageal eosinophilia being a subset of EoE. A clinical situation is described emphasizing the need to recognize and effectively treat both conditions to obtain the best patient outcome.