hands and feet bumps

I have, over the past 15 years, developed very small clear hard bumps on the palms of my hands and the soles of my feet. In places they are so numerous that they actually feel like thickened skin. When my hands are wet for a while, as with swimming, they turn white, sometimes a few slough off. They do not hurt or itch and they never bleed or turn red. My mother and my mother's sister as well as my brother also have these and we don't live in the same regions of the country. What are they?