Incidence of Bullous Pemphigoid in Southern Part of Miyagi Prefecture

Abstract

The incidence of bullous pemphigoid (BP) has been reported in several countries, but there are no available data in Japan. To estimate the incidence of BP in Japan and compare it with those reported from other countries, we retrospectively collected BP cases in the southern part of Miyagi prefecture, which has a total population of 1.354 million inhabitants. These cases were diagnosed between January 2008 and December 2012 at all dermatology clinics and dermatology branches of 2 general hospital located in that area. A total of 75 BP cases (28 male and 47 female) were identified by at least clinical findings and an increased serum level of anti-BP180 antibody. The overall estimated incidence was 42.1 cases per million persons per year in males and 68.2 cases in females. In the population aged 80 years or above, the BP incidence was 642.4 cases per million per year in males and 606.3 cases in females. When we subdivided the cases whose diagnoses were confirmed histologically, the number of cases was 11 for males and 18 for females. Therefore, the overall BP incidence was 16.5 cases per million persons per year in males and 26.1 cases in females. In the population aged 80 years or above, BP incidence was 224.9 cases per million per year for males and 245.8 cases for females. These data suggested that the incidence of BP in Japan is higher than those reported in other countries.