'Sunburn' diaper rash
My DD, 2 years old, seems to get a reoccuring diaper rash. It's not the spotty kind I've seen before, but it looks almost like a sunburn (dark pink). It has a defined border and it extends towards her anus. She doesn't seem to mind it or be hurt by it (No reaction when I change her), but it can't be normal. She isn't teething right now (sometimes brought on a rash). We haven't switched diapers. We tried sensitive wipes, but that didn't seem to help. We try to change her diapers often, we use Desitin and the extra strength one, A&D and Vaseline, and same baby bathtime soap. We switched her to the next largest size of diaper (so it wasn't tight on her) but nothing seems to cure it?
The last time we took her to the doctor, they told us to use Vagisil-didn't work. Then we used an antibiotic (Nystatin?) didn't work. They did a staph test-negative. I believe we tried one more prescription that seemed to help, but what is causing it??