Hey Alex, guinealynx is a great site, and its about the best guinea pig site you'll ever find, so always go there. I couldnt find anything including both hair loss and diarrhea, so it is my belief that she may have too different things. The diarrhea could be many things, from scurvy, which Sheba had, to just a bad peice of lettuce or something. I believe the hairloss is just lice, or ringworm. PLease update as soon as you can!
See ya.