When diaper rash isn't just diaper rash:
"If diaper rash persists despite proper treatment (including regular use of a barrier cream, oatmeal baths, avoiding baby wipes, changing diapers with frequency and, keeping the area clean and dry) the child could actually have a yeast rash."

"Healthy babies have yeast in their stool, and diapers are a perfect breeding ground since yeast like to live in dark, warm, wet places," she said. "If the rash looks bright red, is in the skin folds and if it doesn't get better after three days of treating it, you might want to have your pediatrician take a look to make sure there isn't anything concerning."

Other warnings signs that diaper rash is actually a more serious condition:

The child has an unexplained fever
The skin is oozing pus
The rash has scabbed over
The redness is spreading
There is an abscess or boil