H.
I know there are some yeast/bacterial infections that can cause an odor. Call your ped and ask to talk with a nurse - you may have to leave brief description of problem and name for them to return call. Mention the problem to her and she should be able to tell you if you need to bring your daughter in to get any cultures or such or if there is something over the counter you can use or if it's not really a problem and give an explanation. Just tell the nurse exactly what you wrote - strange smell even when clean and no dirty/wet diaper and no signs of rash. They are your best resource.