ABSTRACT
IgG4-related disease (IgG4-RD) is a new disease entity characterized by elevated serum IgG4 and infiltration of IgG4+ plasma cells in tissue. IgG4-RD can involve various organs, and skin could also be affected. The manifestations of IgG4-related skin disease (IgG4-RSD) are not characteristic, however it usually presents with multiple erythematous nodules or plaques with itching sensation. We report two cases of IgG4-RSD. Histological studies of these cases revealed infiltration of numerous plasma cells and mononuclear cells in the entire dermis. Some plasma cells were strongly positive for IgG4 stain. IgG4-RSD is a treatable disease with systemic corticosteroids. Thus, clinicians should obtain a biopsy and identify IgG4-positive cells for an accurate diagnosis.