Causes of Raynaud’s Phenomenon
Scientists do not know exactly why Raynaud’s phenomenon develops in some people, but they do understand how attacks happen. When a person is exposed to cold, the body tries to slow the loss of heat and maintain its temperature. To do so, blood vessels in the surface layer of the skin constrict (narrow), moving blood from vessels near the surface to those deeper in the body. In people with Raynaud’s phenomenon, blood vessels in the hands and feet react to cold or stress, narrowing quickly and staying constricted for a long period. This causes the skin to turn pale or white, then bluish as the blood left in the vessels becomes depleted of oxygen. Eventually, when you warm up and the vessels expand again, the skin flushes and may tingle or burn. Many factors, including nerve and hormonal signals, control blood flow in skin, and Raynaud’s phenomenon happens when this complex system gets disrupted. Emotional stress releases signaling molecules that cause blood vessels to narrow, which is why anxiety can trigger an attack. More women than men are affected by primary Raynaud’s phenomenon, suggesting that estrogen may play a role in this form. Genes may also be involved: The risk of the condition is higher in people with a relative who has it, but the specific genetic factors have not yet been definitively identified. In secondary Raynaud’s phenomenon, damage to the blood vessels from certain diseases, such as lupus or scleroderma, or work-related exposures likely underlies the condition.