Mysterious Horrible RASH on 19 month old baby

I really need help.
Took her to drs twice and dr says its impetigo. I refuse to believe that because its not ALL over in addition to it not being contagious. I have 3 other children plus me and my husband. We are fine.

My thoughts:
Pityriasis Rosea (with Herald Patch)
Scabies
Eczematous Eruption
Keratosis Pilaris

I know all rashes originate from parasites. I do NOT know what to do!!! It feels HARD underneath. She's got two small ones forming on her left top foot area and another one on her right ankle. So far there seems to be only 5. (4 small and 1 huge)

Please advice. Antibiotics do NOT work. Dr not much of help at all.

Thank you