mottled skin (also known as livedo reticularis) is generally pale cool skin with a reticular pattern of venous congestion, usually of all limbs - not just hands and feet as with Raynaud's phenomenon
Aetiology
benign idiopathic physiologic livedo reticularis
exposure to cold leading to arteriolar vasospasm, especially common in young women.
sometimes called cutis marmorata, typically resolves on warming and is harmless
venous obstruction usually within the trunk
embolism, thrombosis, and cardiac conditions causing impaired circulation can manifest as livedo reticularis
Severe form of this may result in phlegmasia caerula dolens or phlegmasia alba dolens
life threatening thrombosis of ileo-femoral / pelvic veins +/- IVC