The terms Pediatric Autoimmune Neuropsychiatric disorders associated with streptococcal infections (PANDAS), Pediatric acute-onset neuropsychiatric Syndrome (PANS), and Childhood Acute Neuropsychiatric Symptoms (CANS) have been used to describe certain acute onset neuropsychiatric pediatric disorders. This clinical characteristic was unusually abrupt onset of obsessive compulsive symptoms and/or severe eating restrictions and concomitant cognitive, behavioral or neurological symptoms. Because the CANS/PANS criteria define a broad spectrum of neuropsychiatric conditions, the syndrome is presumed to result from a variety of disease mechanisms and to have multiple etiologies, ranging from postinfectious autoimmune and neuroinflammatory disorders to toxic, endocrine or metabolic disorders. We suggest a diagnostic flow-chart in case of acute onset neuropsychiatric syndrome to better define diagnostic criteria, identify possible subtypes and delineate treatment. •Definition of acute-onset neuropsychiatric symptoms triggered by infectious agents.•Clinical characteristic of CANS and PANS are discussed.•Diagnostic criteria and limitations of each one are reviewed.