In younger children we can see thrush orally or anally. Typically we also see some level of constipation, outside yeast outbreaks, and general fussiness or colic. If you look at the websites, anything can be a symptom.
I typically treat with a combination of oral herbal antiyeast and a "safe" yeast as probiotic. But the overall situation should be addressed (other family members, the bathtub, etc.)
I hope this is helpful.