Need help identifying

My almost 6 month old baby started with a rash last Thursday.  She's still exclusively breastfed so no new foods (and I haven't had anything unusual to eat either).  She's eating well, in good spirits, no fever - no symptoms of anything else.  I took her to the pediatrician on Sat, he said probably just a reaction to a virus in her body and just keep an eye on it.

It's still there, one week later.  Not too worrying as their are no other symptoms that I can see.  Except that today, my 2.5 year old has it on her arms and face - just showed up today.  I have an appt for her in the morning but I'm trying to figure it out.

The weird part is that it's even on the bottom of her feet and palms!  Almost heat rash looking but bigger bumps than I've seen on heat rash in the past (unless it has many forms).  My mom said it looks like measles to her, from what she remembered from her childhood.  Anyway, if anyone has any ideas, I have some pics of the rash posted here http://learninglifethroughunschooling.blogspot.com/2007/09/name-that-rash.html

It's much lighter on her torso and the hairy part of her head doesn't seem to have any bumps at all.  But her arms, legs and cheeks are covered with raised red bumps.  The soles of feet and palms of hands have just red circles but they're not raised.  Any help would be appreciated!