Which color change sequence occurs in Raynaud's phenomenon after cold exposure?

• A. White, Red, Blue
• B. Blue, White, Red
• C. White, Blue, Red
• D. Red, White, Blue

Answer: (C)

In Raynaud's phenomenon, cold exposure causes vasospasm of the small digital arteries, which first reduces blood flow and makes the digits pale or white. If the spasm continues and oxygen is depleted, the affected areas take on a blue color due to increased deoxygenated blood. When warmth returns or the spasm resolves, there is rapid dilation and a surge of blood flow, producing redness. This progression—white (pallor) followed by blue (cyanosis) and then red (rubor)—is the typical color sequence seen after cold exposure.