Relationship of skin barrier breakdown and eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is strongly associated with allergic diseases, such as asthma, allergic rhinitis, and atopic dermatitis (AD). Although atopic diseases affect different organs, they share a number of characteristics, such as eosinophil tissue infiltration; T(H)2-biased inflammation involving innate and adaptive immune responses; increased peripheral blood total IgE levels, including specific IgE to environmental allergens; and a chronic disease course.(1) They exhibit a genetic predisposition.(1) Previous observations that airway allergies usually occur before EoE manifestation,(E1) the fact that a challenge to the upper airways in a mouse model leads to eosinophilia in the esophagus,(2,3 )and our recognition that medications effective in asthmatic patients are helpful in patients with EoE(E2,E3) had already placed EoE close to asthma and allergic rhinitis. Although patients with EoE are less frequently affected by AD compared with allergic airway diseases,(2,E1) there are several observations that suggest a close relationship between these 2 different clinical entities because they both share both an impaired epithelial barrier and type 2 inflammation. The main purpose of this article is to emphasize that both AD and EoE exhibit barrier defects contributing to disease development and to address the question of whether skin barrier disruption might contribute to EoE pathogenesis.