I've been trying to figure out what the white spots on my skin are and your blog seems to be the closest match. Like you, it is only on my forarms and a bit on my legs (knee area).
Everywhere I read people seem to suggest that it is tinea versicolor, vitiligo or keratosis pilaris. The pictures I've seen simply don't match what is on my arms. It's almost like water spots right? you can press on them and they fade away temporarily or even if you rub your arm and warm up the skin they seem to dissappear, and they are more visible when your skin is cold. There is no itch no discomfort, just visible spots that are scattered all around barely bigger than freckles. Does that sound right?
I was told a couple of year ago by a uncle of mine who is a Dr. to use selsun blue. I did, nothing happened (good or bad). It has progressively gotten worse, although not by much.
I think we have the same thing, let me know if my description matches yours. Lets figure this thing out! :P
I went to a dermatologist once on a whim, he didn't know and wanted to a biopsy but I wasn't curious enough to shell out the green. But I've had it now for 5-6 years and it is time to get rid of it :P It seems harmless enough it's just kinda ugly.