Suggest Remedy For Rashes With Dry Skin On Abdomen

I have a 3 yo who started with crescent shaped red "rash" on abdomen several months ago. Skin seems dry, but not raised or bumpy. At first we thought is was a bruise, but it is just red, not itchy and will not go away with Hydrocortisone cream. Since then 2 more with similar shape, but different size have appeared.