If it were my step daughter ,I way say to her that I have an issue that is bothering me (thus you are owning the situation) and that you need her help in resolving the issue. Tell her that it really bothers you to have others using your things without your permission or consent. Tell her that you had this same conversation with your daughters when they were younger, and you all agreed to never touch anything of the other's without permission. Tell her that you have noticed that she sometimes uses things of yours and that really bothers you ,but because you have never explained to her how it makes you feel that there was no way for her to know this. At this point, I would ask her what is it that she thinks that you can do to solve the problem.
Sometimes, with my kids I find that rather than stating blame things are more easily resolved when I ask them to provide a solution. Granted, sometimes the solutions are fairly nonsensical, but for the most part they usually come up with some balanced ideas particularly when they do not feel blamed or backed into a corner.
Saying that you experience this with your daughters when they were younger makes it seem more like an issue that most mothers and daughters address at one time or another.
I would not address this with your husband unless the situation becomes extreme. This should be a situation that a mature woman and a teenager can resolve with some quiet discussion and a willingness to hear what the other is saying.
I am not a fan of reporting or telling on a child unless the situation is too extreme for me to address directly with the child.
Some situations can require several conversations and reminders before a good resolution is reached.
I might even suggest that if there is a favorite perfume or brand of makeup of which she is particularly fond that she might add it to her Xmas or birthday list.