C.N.
I treated my daughter - also 4 years old - with probiotics, assuming that she had a systemic yeast issue (as I did several years ago). We used ThreeLac, which is available online. My daugter had had vaginitis consistently since birth, and it cleared up within days of starting the probiotics. I kept her on the "theraputic" dose for about a month. Now whenever the vaginitis seems to be returning I give her one dose of probiotics and it clears.