Little is known about the natural history of children with pediatric autoimmune 
neuropsychiatric disorder associated with streptococcal infections (PANDAS). 
This study prospectively followed 33 children with PANDAS for up to 4.8 years 
(mean 3.3 ± 0.7 years) after enrollment in a 24-week randomized, double-blind, 
placebo-controlled trial of intravenous immunoglobulin (IVIG) (N = 35). Fourteen 
of eighteen children randomized to placebo received open label IVIG 6 weeks 
after the blinded infusion, so follow-up results reported below largely reflect 
outcomes in a population of children who received at least one dose of IVIG. 
Telephone interviews with the parents of participants found that at the time of 
phone follow-up, 29 (88%) were not experiencing clinically significant 
obsessive-compulsive symptoms. During the interim period (6-57 months after 
entering the clinical trial), 24 (72%) had experienced at least one exacerbation 
of PANDAS symptoms, with a median of one exacerbation per child (range 1-12; 
interquartile range 0-3). A variety of treatment modalities, including 
antibiotics, IVIG, psychiatric medications, cognitive behavioral therapy, and 
others, were used to treat these exacerbations, and were often used in 
combination. The outcomes of this cohort are better than those previously 
reported for childhood-onset OCD, which may support conceptualization of PANDAS 
as a subacute illness similar to Sydenham chorea. However, some children 
developed a chronic course of illness, highlighting the need for research that 
identifies specific symptoms or biomarkers that can be used to predict the 
longitudinal course of symptoms in PANDAS.