What Is The Treatment For Rash, Vomiting And Diarrhea Of Child?

i have a n 11 month old daughter that broke into a rash on sunday 1/19/2014. on friday 1/17/2014 i took her to the doctor because she had been throwing up and had a slight diarrhea but no fever, and doctor told me she had an ear infection so he prescribed azhithromicyn and pedilyte for the infection and dehidration. i gave her the 1st dosage on friday which consisted of 5 ml a day for 5 days. she did good, on saturday i gave her the 2nd dosage and she fought me but swallowed it, then on sunday she fought me again but this time she puked it all out plus her milk and slimy saliva. then 1 1/2 hrs later she broke into this rash but she was breathing good no shortness of breath and anything that indicated allergic reaction! took her to doctor yesterday monday 1/20/2014 and they said it could either be environmental allergies or food allergies and only prescribed a type of cream. she has had previous ear infections with no fevers. she has had acid reflux since birth so she is currently taking pepcid, and she was diagnosed with delayed gastric emptying so she takes E.E.S. granules.. please help, don't know what to do. her rash still present