RESUMO
Aseptic meningitis is a known but unusual serious adverse effect of intravenous immunoglobulin (IVIG). It usually resembles infectious meningitis, which makes its diagnosis challenging. In this report, we present the case of a five-and-a-half-year-old Chinese girl with juvenile dermatomyositis (JDM) who presented with signs of meningismus 21 hours after the initiation of IVIG infusion. Her blood work at diagnosis showed neutrophilia and lymphopenia. The cerebrospinal fluid (CSF) analysis demonstrated neutrophilic pleocytosis, hyperproteinorrachia, and normoglycorrhachia. All microbiological tests were negative. The child fully recovered within 72 hours without neurological sequelae. IVIG-induced aseptic meningitis remains a diagnosis of exclusion. Although it is rare, pediatricians should be aware of this complication and avoid unnecessary investigations or treatment.