I had this issue (posted about it back in '04 earlier in this thread!!) many times. I found it is the golfers vasculitis. My doctor kept telling me is psoriasis or eczema...I finally brought her in photos I had taken on my latest trip!! She showed other doctors and they said the same thing. I finally found the golfers vasculitis info...printed it out for her. She was amazed!!!!
The thing of it is this...this happens to primarily females, who are over 40, are fair skinned and tend to be a bit, how shall I say this....um, 'fluffy'!! I fit all those paramters. While I am only about 15-20 pounds 'fluffy', it still is enough to impact me.
Well.....on one visit to the doctor about 2 years ago, I mentioned that it happened again. The doctor got this sickly shade of white, took out my file and just said...'OMG....your blood pressure meds are contributing to this!!!' Now, why she never saw that before I'll never know. But, I changed the meds and it happens very seldom now.
It makes no difference if I wear socks, pants, sunscreen...sit on the ground, pavement. It's all the same to me.