What Causes Small Red Circular Patch On Lower Legs?

I am a fit, active and thin 55 y/o woman and switched to a standing desk for work last year. I developed a small red circular patch about the size of a quarter on my lower leg and was told it was Statis Dermatits. it doesn't itch and has turned a brownish red. I use moisturizer and rub it (as instructed by MD), but can't seem to get rid of this red/brown area. It isn't raised or broken skin. Is there any way to reduce the look of the brown staining on the skin? I wear compression socks now and move more when at my desk. Will this be with me forever?