Impossible to say unless she's willing to go with you to an M.D. I developed a rash and itch on my chest and back. Asked the Dermatologist about it, and she said it's something called Grover's disease. Fairly rare, nobody knows what causes it, treat it with steroid cream, but it may come back (it does). Not dangerous, not contagious, just annoying. There are probably a lot of things like that, and only a qualified professional will know for sure.