PANS stands for Pediatric Acute-onset Neuropsychiatric Syndrome. PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections) is a subtype of PANS with a specific known trigger: strep infection. Both involve the sudden, dramatic onset of neuropsychiatric symptoms in children — severe OCD, tics, anxiety, emotional dysregulation, food restrictions, sleep disturbances, and behavioral regression — triggered by an underlying autoimmune response to infection. PANDAS is specifically strep-triggered; PANS can be triggered by other infections (Lyme, mycoplasma, strep) or sometimes has no identifiable trigger.