IgG4-related disease (RD) is a relatively new entity, which was first proposed in 2001. Since then, clinical and pathological characteristics of the disease have been investigated. As
IgG4-RD has been studied extensively, the diagnostic criteria for
IgG4-RD of each organ and the comprehensive diagnostic criteria for
IgG4-RD have also been developed. However, one of the biggest challenges in the field is distinguishing between
IgG4-RD and mimickers, which show overlapping features with
IgG4-RD. It is now known that some non-IgG4-RDs may meet the diagnostic criteria of
IgG4-RD and can be misdiagnosed as
IgG4-RD. However, accurate diagnosis is crucial, as the treatments for
IgG4-RD and those for other diseases that may be misdiagnosed as
IgG4-RD are different. This prompted us to create and propose comprehensive exclusion criteria for
IgG4-RD. In this review, we have described the comprehensive exclusion criteria for
IgG4-RD, with a historical overview of the disease. These exclusion criteria were recently created by the Research Program for Intractable Disease of the Ministry of Health, Labor, and Welfare of Japan, All Japan
IgG4 team, to support correct and accurate diagnosis of
IgG4-RD.