title: Immunoglobulin G4-related disease and its skin manifestations.
abstract: Immunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory condition characterized by tissue infiltration with IgG4+plasma cells and an elevated serum IgG4 level. It usually occurs in middle-aged or older patients, with male predominance, and can involve multiple organs synchronously or metachronously. Patients with IgG4-RD generally respond to steroid therapy. IgG4-related skin lesions are typically erythematous and itchy plaques, subcutaneous nodules, or papules like prurigo nodularis located on the head and neck areas. Histologically, lymphoplasmacytic infiltrates with abundant IgG4+ plasma cells are seen in the dermis and/or subcutaneous tissue. The skin condition of IgG4-RD does not necessarily exhibit infiltration of IgG4+plasma cells, which is a prerequisite for IgG4-related skin disease, but such skin lesions without infiltration by IgG4+plasma cells can be included in the skin manifestations of IgG4-RD.
authors.affiliation: Department of Dermatology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Takayama
authors.affiliation: Department of Dermatology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ueno
authors.affiliation: Department of Dermatology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Hidehisa
authors.initials: H
authors.lastname: Saeki
mesh_terms: D006801:Humans; D006942:Hypergammaglobulinemia / Q000150:complications / Q000276:immunology*; D007074:Immunoglobulin G / Q000276:immunology*; D012871:Skin Diseases / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology
chemical_list: D007074:Immunoglobulin G
keywords: hypergammaglobulinemia; immunoglobulin G4-related disease; immunoglobulin G4-related skin disease; leukocytoclastic vasculitis; skin