Hi C.,
If the yeast is on your little one's skin, then her entire body is eaten up with it. You really need to work on it from the inside out. First of all, you need to remove every bit of sugar from her diet. That doesnt just mean sweets but white bread, white rice and white potatoes. Sugar breeds yeast and keeps it alive. (if you've ever baked bread you feed your yeast with a teaspoon of sugar a day to keep it alive.)
The next thing is get her on a prebiotic/probiotic right away. Yogurt is not good enough for the seriousness of what she has. Don't worry but act right away. Yeast breaks down the immune system and can lead to some serious diseases if not caught early.
There is a product manufactured by Intensive Nutrition that is called Tanalbit (much safer than diflucan) that should get rid of it. It is appropriate for three year old children and older. I have used it in the past and so have my children. Yeast/Candida is at epidemic proportions today because of our diets...even McDonalds puts sugar on their fries....arrrrgh!
I keep my family on a probiotic/prebiotic for maintenance. Most people should...
Hope this helps.
M.
PS The website for the Tanalbit is www.intensivenutrition.com