I have red splotches on both lower arms, upper arms, shoulders front and back, chin, and my upper chest area. What is this?

It started on my right forearm about ten years ago and progressed to the areas mentioned in the question.  It is not bumpy or upraised, it is smooth.  The rash is circular splotches with light areas in the center.  It doesn't itch or hurt, but sometimes it is fire red, though it does not burn.  Other times it is paler, but still red.

It seems like it is simply part of my skin.  It gets very red when I am using my arms a lot, ie-typing, cooking, stirring, etc...