Strange rash on 2 yr old ds

[klocke]

My yds has developed a strange rash on the side of his tush. It started about a week ago but was completely different. It originally looked like a heat rash, just kinda red and splotchy. Last night when I undressed him for his bath I noticed it has turned into more blistery looking bumps. It itches him terribly. He has prescription Cortisone cream for his eczema so I have tried putting that on it and it doesn't seem to change it any. Any ideas what it could be? Or what to do with it? Doctor isn't open until Monday so I'm at a loss here on what it is. Oh and I checked and it is nowhere else on his body.

http://i36.photobucket.com/albums/e2...e/DSCF9318.jpg

http://i36.photobucket.com/albums/e2...e/DSCF9314.jpg

[springmum]

That is so weird, my 23 mont old has been getting the exact same thing (although with smaller non-blistered bumps) in the exact same spot for a few months now.

It comes and goes, and only seems to itch a little. He has food sensitivities so I thought it might be food related, but I'm not noticing a pattern for that yet - I could just be missing it though.
I thought it was his 7th gen diapers b/c we were using those more than cloth lately. I thought it was related to his bum being moist and then sitting on the potty for too long causing irritation. I've been scratching my head about this for a while. It's no where else on his body either.

I usually do a swipe of TTO after the bath, before bed, and that seems to help a little. I also fold down his diaper to keep that area dry.
I've tried calendula cream & our homeopathic eczema cream which never helped.

I haven't seen a hcp for it yet either, b/c it does go away, and doesn't get worse. I'm going to mention it at his 2 year check-up though.

Let me know if you find out any more info too, hopefully we can find the cause!