Eosinophilic esophagitis: is it all allergies?

Eosinophilic esophagitis (EE) is an increasingly recognized disorder in the adult population, most often manifested by symptoms of dysphagia and food impaction. Mechanisms involving eotaxin-3, interleukin 5, and signal transducer and activator of transcription 6 have been studied and may represent future therapeutic targets. Patients commonly have a personal and family history of atopy, and both food allergies and aeroallergens have also been investigated as triggers of EE. Traditional allergy-testing methods, including skin prick testing and specific IgE testing, have been used to identify food and environmental allergies. However, new studies suggest that patch testing could add to diagnostic accuracy in EE because the disorder might not be a classic type I allergic response. Although studies of treatment of adults with EE have thus far focused on swallowed fluticasone proprionate, many trials in children have assessed the efficacy of food elimination and elemental diets. These diets, which have been extremely successful in reducing symptoms, have also been shown to induce histological improvement and remission. No similar studies have been conducted in adults; the tolerability of such an intervention may prove more difficult in this population. This article reviews the underlying pathophysiology of EE and describes evolving options for more accurately identifying food and environmental allergies. We also discuss the pediatric trials using food elimination and avoidance diets and suggest that this type of intervention may be an important area of future research in the adult population.