Blotchy Skin Rashes On The Body Of A Child. What Could They Be?

Hi! My daughter has a blotchy red rash all over her body......behind the knees, in the elbow , tummy, diaper area, behind the neck, on her back etc. She doesn t seen to be bothered by it. She doesn t scratch it and it doesn t seem to hurt/ burn when I bathe her or put cream on. It looks like welts, but they are not raised at all. They are a bright red. There is no other colour like white. We took her to the dr today and he wasn t sure what it was. I thought it may be a yeast infection but the symptoms sound different. I know it s hard to diagnose without seeing it but would you have any ideas of what this could be? Thank you!