When the blood flow reduces with response to cold or emotional stress in fingers toes and occasionally even in other areas, the phenomenon is termed as Raynaud's. This condition causes discoloration in the affected areas and may also cause nails to become brittle with longitudinal ridges.
Here are some things people with Raynaud's can surely relate to.
... you curse cold for turning your hands into fleshy icicles.
It doesn't even matter if it is cold outside.
The reason being the rush of blood.