Random blotches

I have recently started getting small red blotches all over my body but particularly my neck and chest area they are generally small (never larger than a 10p) but itchy and never connect together. When they first appear they are just red and itchy and then they go dry.

Not sure it’s relevant but just incase I did have a blood transfusion 3 months ago however none of my booklets give me an incline to it being a link to this