How To Cure Red Blotches On Upper Arms?

I have recently developed red blotches on my upper arms. I don't notice anything on other parts of my body. Skin is clearer in the morning and when I get up and start moving around, upper arms get blotchy. There isn't anything on face, chest or legs. No itching or raised skin. All skin in smooth. I'm 43, 5'4", 140 lbs. and healthy.