Remarkable differences in the epidemiology of pemphigus among two ethnic populations in the same geographic region

Background The epidemiology of pemphigus in different ethnic populations exposed to similar environments is unknown. Trends in the incidence of pemphigus based on an immunopathologically validated cohort have not been investigated. Objectives We sought to estimate the incidence of pemphigus in Israel and to investigate differences between the 2 major ethnic populations. Methods Pemphigus incidence was retrospectively estimated from January 2000 to December 2015 in 2 Israeli regions with a total population of 1.56 million inhabitants. Results One hundred eighty patients with pemphigus (mean age, 54.70 ± 16 years) were identified. The overall estimated incidence was 7.2 per million inhabitants per year (95% confidence interval, 6.2-8.3). The incidence in the Jewish population was threefold higher than that in Arabs (9.6 vs 3.2 cases per million per year, respectively; P < .0001) and higher among women than men (9 vs 5.3 cases per million per year, respectively; P < .0001). The incidence decreased from 8.4 cases per million per year in 2000 to 2005 to 7.0 and 6.0 (95% confidence interval, 4.5-7.9) in 2006 to 2010 and 2011 to 2015, respectively (P = .068). Limitations This study was limited by the retrospective design and the small population. Conclusions The incidence of pemphigus in Israel is among the highest reported worldwide and is significantly more frequent among Jews.