My DS has them quite often Annette. It has crossed my mind that it could be from the milk as I am not sure I ever noticed them while he was on Nutramigen but have since he has been on cow's milk but I also just don't feel that they are milk related...if that makes sense.
I am starting to notice them coinciding with some teething, though that may not be it. I'm not 100% convinced of that either! Any chance your LO is getting her molars?