What Could Dry Skin And Rashes On A Toddler's Torso Indicate?

my daughter is 2 years old and has a spotty rash over her torso, that seems to get worse when she is hot, especially after bathing. Then it dies down, when she cools off, but never totally goes away. Feels more like dry skin when it cools down. She has had soya oil for the bath and aqueous cream, but nothing seems to be working and its getting worse