I get bumps on the tops of my arms and legs that are similar to what you
describe.  My dermatologist told me that there was nothing that I could
do, that it was some kind of rash that people who have allergies get, but
I don't get allergies.  I didn't have bumps like this until I moved to
Fairbanks, Alaska (where there is little sun in the winter) and a lot of
my friends also have these type of bumps.  Mine too disappear when I get
some sun.  I also use a moisturizing soap on my skin and that seems to
help a little.  Sallette