What is this rash

[BelleEtoile]

DS is 15 months.
He has had this rash since Friday.
He is not scratching it and doesn't seem to bother him.
To my knowledge he hasn't had any contact with anything different or unusual.
He doesn't have a temperature.

It started on Friday just below his knees, spread up and down his legs, a few spots on his chest and tummy and a some blotches on his arms.

He had his MMR vaccine 9 days ago and was off form for about a week - clingy, temp, vomited four times, lack of appetite (although it could have been a tummy bug)

Could it be a post vaccine rash?

Dd got the exact same rash after her MMR, it does say on the nhs website that there can be a reaction up to 1-3 weeks afterwards if I remember correctly. I’d keep an eye on it, and if it gets worse, or a temp increase I’d call 111 for advice. But if happy in self I wouldn’t worry too much.

Thank you @TeddyIsaHe! Thats good to know!
I did read that informations on the NHS website and it does indeed fit the timeframe.
I asked the nurse who administered the vaccine but she had never seen a post vaccine rash before so couldn't advise.