I'm calling the pediatrician when they open, but I thought I'd see if anyone knows what this might be. Avery had Roseola last week, which is more of a spotted rash, but it pretty much cleared up and now this morning her whole body looks like this:

Can anyone give me some insight?

Re: Anyone know what this is? (PIP) *updated*
Well, Roseola is speckled, so she still has some of that, but this new rash looks more like a blotchy sunburn. I would think it was diaper rash except that it's all over her body. I'll google fifths disease though to see if that matches.
BFP #2 5/27/12. EDD 2/1/13. m/c and D&C 6/21/12.
Could it be new laundry detergent, dryer sheets, fabric softener? Did you change her soap or her shampoo?
I can't think of anything
I did buy a new brand of wipes, but her diaper area is the only area that's NOT affected.
We've got an appointment at 10:45 PST. I'll update in a few hours!
Thanks for all the thoughts guys. We're back from the pediatrician. He's not sure what it is either, but his guesses were:
1. An allergic reaction to something
2. A new virus (unlikely since people don't usually get new viruses while they're fighting off an old one)
3. A rash caused by her virus last week, which would mean that it wasn't Roseola.
She had such a textbook case of Roseola that I'm inclined to believe #1. I just hope I have a moment of inspiration and figure out what it was caused by.
The pedi said she could have 0.5 tsp of Benadryl 3 times per day and that should at least make her feel better. After buying it, the package clearly says "do not use" for 2 years and under. For 2-4 years it says "do not use unless directed by a doctor." I trust my doctor, but that made me a little uncomfortable. Has anyone else given Benadryl?
We give benedryl all the time for random food allergies/enviromental allergies that pop up. Last week he had hives due to a honey allergy we (obviously) just found. They told me a full tsp, and then 1/2 tsp every three hours for 24 hours. It makes him sleepy, but otherwise it's fine.
We have given Benadryl (3/4 tsp.) a few times now for when colds have him so gunked up he can't breathe. It's slightly off label, but his pedi suggested it to help dry him out and it helps A TON. I wouldn't be afraid to use it.
Ginny DX 21-Hydroxylase Deficiency Congenital Adrenal Hyperplasia
Charlie DX Specific Antibody Deficiency & ASD