Raynaud’s disease is when the fingers turn first white, then blue, then red, usually when the person is exposed to cold or stress.

1. The fingers turn white as the blood vessels entering the fingers (the arterioles) constrict causing decreased bright red blood to reach them.
2. The fingers turn blue as the oxygen in the tissues is depleted.
3. Then, they turn red as the arterioles expand again, causing red blood to enter the fingers.

Raynaud’s phenomenon is classified as either primary or secondary. People with scleroderma (or other autoimmune diseases) have secondary raynaud’s; many healthy people (women especially) have primary raynauds and never develop any autoimmune disease.