Raynaud ’ s phenomenon is a condition that affects blood flow to the extremities, causing them to turn pale, blue, and red in response to cold or stress. Learn about the two types of Raynaud ’ s phenomenon , how they are diagnosed and treated, and what factors increase the risk of developing them. Raynaud's phenomenon (disease) occurs due to spasms of blood vessels. Raynaud's phenomenon is a type of vascular disease characterized by color changes of the skin, most commonly after exposure to cold. The cause of Raynaud's phenomenon is unknown, although abnormal nerve control of blood-vessel diameter and nerve sensitivity to cold is suspected of being involved. What is Raynaud phenomenon ? Raynaud phenomenon is an episodic reduction in the blood supply to the fingers, toes, or nipple occurring mainly in response to cold (vasospastic disease). Who gets Raynaud phenomenon ? Raynaud phenomenon can be divided into two main types: Primary Raynaud phenomenon , also known as Raynaud Disease. This is not associated with any other conditions. It affects at least one in five young women, and is less common in males, children and older individuals. It as an ... Raynaud's phenomenon (RP) is a common vasospastic condition which affects ~5% of the general population. The majority of individuals have primary RP; however, Raynaud's can also occur secondary to a broad range of underlying medical conditions and ...