What is Raynaud's?

Raynaud's phenomenon is a condition in which small blood vessels, most often in the fingers and toes, overreact to cold temperatures or stress by narrowing excessively. This restricts blood flow, causing the affected areas to turn white, then blue, and then red as blood flow returns.

Episodes are often accompanied by numbness, tingling, or pain, and can last from a few minutes to a couple of hours. Most cases are 'primary' Raynaud's with no underlying cause, though it can occasionally be linked to autoimmune conditions.