Why do my feet turn purple when cold?

Sign of PVD: May sign of arterial or venous problem. Seek your doctor advice.

Purple: It could also be raynauds - either way an evaluation is indicated

Blood not returning: This is indicative, of the blood not wanting to go back to your heart. Your venous system is not working properly. You should be seen by vascular disease specialist for consultation. Especially if you have a lot of varicose burns that you can see and/or pain when walking.

Blood shunted away: normally when the body gets cold it tries to maintain it core temperature around 98.6deg. When it gets cold, blood is shunted away from the extremities to reduce heat loss so fingers and toes can be a bit purplish. However if you are a smoker or have a disease called Raynauds that could make this situation much worse