A quick guide to what may be causing it, why it matters, and what you can do about it. If your fingers or toes keep going dark, cold, or purple, your body is trying to tell you something. Sometimes this happens because the tiny blood vessels in your fingers and toes suddenly narrow too much, so less blood gets through for a while. This can happen in the cold, during stress, or after sitting still too long. A common reason is Raynaud’s, which often affects fingers and toes and