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Raynaud's Phenomenon
What Happens During an Attack?
For most people, an attack is usually triggered by exposure to cold or emotional stress. In general, attacks affect the fingers or toes but may affect the nose, lips, or ear lobes.
Reduced Blood Supply to the Extremities
When a person is exposed to cold, the body's normal response is to slow the loss of heat and preserve its core temperature. To maintain this temperature, the blood vessels that control blood flow to the skin surface move blood from arteries near the surface to veins deeper in the body. For people who have Raynaud's phenomenon, this normal body response is intensified by the sudden spasmodic contractions of the small blood vessels (arterioles) that supply blood to the fingers and toes. The arteries of the fingers and toes may also collapse. As a result, the blood supply to the extremities is greatly decreased, causing a reaction that includes skin discoloration and other changes.
Changes in Skin Color and Sensation
Once the attack begins, a person may experience three phases of skin color changes (white, blue, and red) in the fingers or toes. The order of the changes of color is not the same for all people, and not everyone has all three colors. Pallor (whiteness) may occur in response to spasm of the arterioles and the resulting collapse of the digital arteries. Cyanosis (blueness) may appear because the fingers or toes are not getting enough oxygen-rich blood. The fingers or toes may also feel cold and numb. Finally, as the arterioles dilate (relax) and blood returns to the digits, rubor (redness) may occur. As the attack ends, throbbing and tingling may occur in the fingers and toes. An attack can last from less than a minute to several hours.
How Is Raynaud's Phenomenon Classified?
How Does a Doctor Diagnose Raynaud's Phenomenon?
