Macrophage Activation Syndrome as Onset of Systemic Lupus Erythematosus: A Case Report

Macrophage activation syndrome (MAS) belongs to the hemophagocytic lymphohistiocytosis group of diseases. It is an anatomo-clinical condition resulting from the inappropriate proliferation and activation of macrophagic cells. This rare but potentially fatal syndrome can be primary or secondary to certain pathologies dominated by infections and neoplasia. In adults, MAS is rarely associated with systemic lupus erythematosus, but it arises as a complication of several systemic autoimmune diseases. Here we report the case of 30-year-old woman who presented with a pruritic rush. She met the Systemic Lupus International Collaborating Clinics (CLICC) criteria for the diagnosis of Systemic Lupus Erythematosus (SLE). The bone marrow showed the presence of abundant hemosiderophages with focal hemophagocytosis. Due to the overlap in clinical findings, SLE-associated MAS might be underdiagnosed. This case represents the importance of prompt diagnosis and treatment of such a potentially fatal clinical syndrome.