Is their a reason why I have blue nails?

Blue nails. Blue nails, or more formally azure lunula, are characterized by a blue discoloration of the lunulae, seen in argyria and cases of hepatolenticular degeneration (wilson's disease), also having been reported in hemoglobin m disease and hereditary acrolabial telangiectases. In wilson's disease the blue color involves the lunula (most intense pigmentation) and fades proximally. See your doctor.