@anamur-- Yes, they do look different. A yeast infection skin rash is more raised than a regular diaper rash and can have scales. Yeast infection rash also tends to form in clusters and may be redder in color.
My daughter also had a yeast infection rash as a newborn. I thought it was a diaper rash at first but it became obvious that it was something else because the rash didn't get better at all after several days. Usually a diaper rash will get better after a few days of treatment with ointments. A yeast infection rash doesn't get better without prescription treatments.