Sorry, gp rang back and said bring him in, He's had a cold virus thing for a few days temp etc started with a rash behind one ear yesterday morning which spread to his face, neck and chest, it's now all over him. He has had first mmr but not had the booster yet. Saw the GP who was great said it could be measles or a viral rash but know way of knowing at the moment, just wait and see how it developed. She advised me and DH to have a blood test tomorrow to see if we have the antibodies.
Thanks other twin has temp and very grumpy but no rash yet! They were due to have their booster a few weeks ago but both had flu so was advised to leave it till they were well. Gp said a lot measles around at the moment.
The main difference between a post viral rash and a measles rash is that the post viral rash only develops towards the end of the illness when the child is already recovering and starting to feel better.