Can baby girls get full on yeast infections?

I mean full on by discharge, the rash, burning itching everything that adult women get. 
If so how would the doctor treat it? And what on earth is causing it? She's not sitting in a dirty diaper, if she's wet she's changed within 30 minutes. If she's pooped and we don't notice it right off the bat then she's probably in it 10 minutes or so. 
If not what does it mean when a baby girl has vaginal discharge? It's my sisters baby and she's using the vaginal yeast infection cream that the doctor gave her but it's not letting up. I'm just so confused I didn't know babies could have vaginal discharge. It's alarming.