Rash? Spots? 7 year old.

This literally just came up on my son's torso he's 7 and said it itches.

I am waiting a call back from docs but thought I'd post here too.

Any ideas?

THANK YOU for everyone that commented, the doctor didn't even phone back. So thanks guys I've took it as an allergic retraction to something. Just trying to figure out what as we have done nothing different (or so we think).

Again thanks for answering x