Differences in adult eosinophilic esophagitis between Japan and Western countries.

Several similarities and differences have been reported in the epidemiology and clinical characteristics of adult eosinophilic esophagitis (EoE) between Japan and Western countries. To review the similarities and differences in adult EoE between Japan and Western countries with respect to asymptomatic cases, the efficacy of proton pump inhibitors (PPIs) and potassium-competitive acid blockers (P-CABs), gene profiles, and disease severity. A PubMed search was performed to identify relevant publications using the following search terms: "eosinophilic esophagitis," "esophageal eosinophilia," "epidemiology," "natural history," "asymptomatic," "PPI," "P-CAB," "Japan," and "Japanese." Asymptomatic EoE has been reported only in Japan, primarily during gastric cancer screening and routine health check-ups, and progression from asymptomatic EoE to symptomatic EoE is uncommon. The efficacy of PPIs and P-CABs for the treatment of EoE appears to be higher in Japan than in Western countries. Severe fibrostenotic cases requiring emergency visits or endoscopic dilation are rare in Japan. The gene expression profile of EoE in Japan is similar to that reported in the United States, and no differences in gene expression have been observed between patients with EoE and those with asymptomatic EoE in Japan. We hypothesize that early detection and diagnosis of adult EoE in Japan may contribute to the high efficacy of PPIs and P-CABs and that early therapeutic intervention may prevent the development of fibrostenosis and severe disease.