2 year old - rash on legs

[GBoxall]

Hi, I collected my 2 year old from Nursery today to this rash. Does anyone have any ideas what it could be? Thank you :)

Look like heat rash - is it warm to the touch? Is it anywhere else on him?

@Thislittlepiggywenttotheestateagents It’s pretty localised to his legs at the minute. Just waiting for him to wake up, so I can check this morning! It was quite warm last night. Thank you so much for replying, I really appreciate it! :)