Hello and welcome to HC
Sorry to hear about Nana.
Does her hair appear to be missing/thinner all over or is it missing in patches (like behind her ears)? Is she scratching more than usual?
I think there is a restriction for new members on posting photos so hopefully you'll manage to post some soon.
I think Harry Hamster is the best food for Syrians (though I don't know by how much as I don't have syrians myself) so it might be worth switching her food, especially if she doesn't seem to be liking the nature's touch. Is she not only eating certain bits of it, or just less of it?
Also what type of substrate do you use? Does the skin seem red where the fur is thinner?