Multisystem Inflammatory Syndrome in Infant with Negative SARS-CoV-2 RT-PCR and Antibodies

Since the declaration of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in March 2020 by the World Health Organization (WHO), there has been an emergence of a new syndrome termed multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. MIS-C is defined by the presence of fever, systemic inflammation and multiorgan dysfunction in association with SARS-CoV-2 infection or COVID-19 exposure. Knowledge of this syndrome’s presentation and pathophysiology is constantly evolving as more cases are reported in the literature. This case identifies a 3-month-old patient who tested negative for SARS-CoV-2 antigen, reverse transcriptase polymerase chain reaction (RT-PCR) and antibodies but qualified for MIS-C diagnosis. To the best of our knowledge and through extensive research at the time of diagnosing and reporting this condition to the healthcare authorities, we report the youngest pediatric patient with MIS-C diagnosis. We document this case to contribute to further understanding the variable manifestations of MIS-C and the importance of early diagnosis and treatment with intravenous immunoglobulin (IVIG).