What Causes Circular Red Patches On Body?

Good Afternoon from the UK. I just wanted to ask as I have circular patches of red skin appearing on my trunk of my body. It started with one on the top of my bottom, now they seem to be making a line upwards. They are not itchy but look like broken blood vessel buises, but a re dry in nature. I have never experienced skin problems and I am just concerned as i have been feeling a little low lately. I look forward to any advice. Someone did mention shingles to me but having looked into, they are not blister like patches.