What is this?

Samantha • pregnant with baby #2

This is on my wrist. I had this on my left wrist a couple days ago and it was gone by the end of the day and now its on my right wrist. I know obviously it is a rash, but what kind? It is itchy with 4 large bumps and a whole bunch of tiny bumps. it's not ring worm and i dont have any skin disorders or diseases like eczema or psoriasis. It hasn't been in an enclosed area to be a heat rash either. I havent worn anything on it.

What do you think?