Second Episode of Multisystem Inflammatory Syndrome in Children: Relapse, Rebound, or Recurrence?

Two Distinct Illnesses Consistent With MIS-C in a Pediatric Patient

Multisystem inflammatory syndrome in children (MIS-C) is a severe inflammatory response described in children after infection with severe acute respiratory syndrome coronavirus 2. We present a case of a 9-year-old African American boy with 2 distinct illnesses that were both consistent with MIS-C. He first presented in the early stages of our understanding of MIS-C with predominantly neurologic and gastrointestinal symptoms and demonstrated elevated inflammatory markers consistent with MIS-C. He was treated with intravenous immunoglobulin with complete resolution of signs and symptoms. After 7 months of good health, he returned with a second, distinct illness characterized by fever, rash, gastrointestinal symptoms, and elevated inflammatory markers that met the criteria for MIS-C. In addition, we identified new dilatation of the left anterior descending coronary artery. He improved rapidly after treatment with intravenous immunoglobulin, aspirin, and steroids. Our report highlights the need to achieve a better understanding of this entity's pathogenesis and clinical course and to improve anticipatory guidance for children with MIS-C.