Inducible skin-associated lymphoid tissue (iSALT) in a patient with Schnitzler syndrome who manifested wheals on recurrent localized erythema

Schnitzler syndrome is characterized by a chronic urticarial rash with an intermittent fever, and is considered to be an acquired form of autoinflammatory syndrome because its clinical phenotypes are similar to cryopyrin-associated periodic syndrome with a gain-of-function mutation in NLRP3.1 Patients with Schnitzler syndrome also exhibit IgM monoclonal gammopathy, and 15-20% of patients eventually develop a lymphoproliferative disorder resembling Waldenstrom macroglobulinemia with an MYD88 mutation.2 At present, the precise pathogenesis of Schnitzler syndrome remains unknown.