RESUMEN
Schnitzler syndrome (SchS) is a rare autoinflammatory disease characterized by chronic urticarial rash and monoclonal immunoglobulin M (IgM) or IgG gammopathy. Viruses, including COVID-19, activate the innate immune system, therefore SchS, in which the innate immune system is improperly activated, is hypothesized to be exacerbated by viral infection. However, there were no reported SchS cases exacerbated by any viral infection. Here, we report a SchS case with an unusual IgA gammopathy manifested and exacerbated by COVID-19 infection. This report advocates the need for recognizing unusual cases of SchS with monoclonal IgA, and following up on paraprotein like IgA even when it is initially undetectable in cases with SchS symptoms. We also hypothesize that existing autoinflammatory diseases may be exacerbated by COVID-19 infection in the case of a combination of these diseases.
RESUMEN
A 71-year-old woman was presented with 5-year history of recurrent, multiple, painful or tender, erythematous plaques on her lower limbs accompanied by fever and arthralgia. Histopathological findings showed a dense infiltration of mature neutrophils in the upper and mid dermis without leukocytoclastic vasculitis. These clinical and histopathological findings were consistent with Sweet's syndrome. The laboratory investigations demonstrated elevated ESR and IgA gammopathy, but no leukocytosis or neutrophilia. Her eruption revealed good responses to systemic steroid therapy. We herein describe a patient with Sweet's syndrome without leukocytosis, probably associated with a benign IgA gammopathy.