My son 2 yo has a skin rash?

my son has a skin rash that started on his wrist it is small bumps that look like pimples at firs their were only like 20 or 30 of them in a patch now they seem to be spreading to hie legs hips up his arms and on his back they are reddest after naps|||This could be a common viral infection of the skin called molluscum contagiosum. They are similar to warts but much more superficial and they tend to spread more rapidly. I would have a dermatologist look at the rash before it spreads much further.|||I'd call his MD and talk to him/her about it. It could be an allergy, dermatitis, or something viral. It's hard to say - keep a mental note about the foods he eats, new soaps - and if he's been around any sick kids.