J.B.
Have you changed your detergent to a completely fragrance and dye-free type? Also, have you had her allergy tested for food allergies? This may seem gross/TMI, but people can have anal yeast infections as well as vaginal or genital (since men also get them) infections. If there is an anal infection, it can easily transfer to the genital region, especially if she's not wiping in the right direction. Allergies to certain foods can cause anal yeast infections even though she may not be having other reactions to the foods. Certain nuts, dairy, wheat -check it out!