J.G.
Since you are in Lafayette I recommend you go see Dr Robert G. Greenberg Dermatologist (san ramon) ###-###-####....he is a miracle worker!!
He takes a few weeks to get into but WELL worth the wait....
in the mean time go get CERAVE CLEANSER and CERAVE CREAM (NOT lotions!!) use the cleanser everytime you clean/bathe...and use the otc Hydrocortisone 2 times a day and use the CEREVE cream multiple times a day all over...(my son calles it "lubing" kinda funny!)
this plus the Dermatologist will have her under control in no time and she will be a happy itch free rash free baby again!
Good Luck
J