Hives, heat rash or chickenpox! Oh my!

Last night, after Kyle fell asleep, I decided to get up and watch some television. He woke a few hours later and I noticed as we were going to lay down again that he had red spots on his skin. The redness was in various spots. While he has eczema, this is not look like eczema. I quickly called Shannon into the bedroom to look. I told him that I think it's hives and he thinks it's a heat rash. He also had red hives on his thigh that he was scratching.

Since he has eczema, I have ruled out any new detergent, lotion and soaps that I use on him.  The products I have used aren't new to him.  

Now we're not sure if it could be chickenpox.