She can get some steroid cream if the rashes last for a while (it makes them go away faster) and if she gets itchy, something like
Xyzal, Zyrtec or Benadryl works well. The steroid cream and Xyzal are by prescripion...Zyrtec and Benadryl are OTC
If she finds she's having a problem with most of the commerical soaps, making her own plant-based, oil soap might be a good option. If she wants more info about that, leave a note on my page and I'll be happy to tell her more.
Lots of luck!