What is this rash?

[MoreEqualPig]

My 6y old has came out in spots on his legs, feet, hands and nappy area. He is non verbal so can't tell me how he feels, but they don't seem itchy, he doesn't have a fever or any other symptoms.
My first thought was chickenpox, but he is vaccinated, and surely there would be spots on his chest or back?

They do look like the start of chicken pox. My daughter has been vaccinated but she still ended up catching them from her sister. (We got her vaccinated as soon as her sister came out in them).
Hers started with a few on her arm and a few on her back. They never really came fully out, just stayed like that and went away after about 4 days. She had about 12 in total.

Hi OP, based on the fact you've said he's vaccinated against chicken pox, and the fact that hand foot and mouth is sweeping through our house as I type this, it could very well be HFM.

Baby has caught it from nursery, eldest now has it very mildly as he had it years ago, however DH is VERY sore and uncomfortable right now! All in the same places you've described, in fact DH can hardly walk, I think it hits adults much harder though.

I'd say hand foot and mouth too given where you say the spots are