The main cause of Raynaud’s disease is an exaggerated constriction of small blood vessels in the fingers and toes in response to cold temperatures or emotional stress. In most cases, this overreaction happens without any identifiable underlying disease, a form called primary Raynaud’s. When it does stem from another condition, autoimmune diseases like scleroderma are the most common culprit.
How the Blood Vessel Overreaction Works
When anyone is exposed to cold, the body naturally narrows blood vessels near the skin’s surface to conserve heat and protect internal organs. This process is driven by the sympathetic nervous system, which releases a chemical messenger called norepinephrine that tells blood vessel walls to tighten. In Raynaud’s, this normal protective response becomes dramatically overblown.
The key players are specific receptors on the smooth muscle cells lining small arteries in the fingers and toes. When cooling occurs, a chain reaction involving reactive oxygen species and structural changes inside those muscle cells pushes certain receptors to the cell surface, where they become highly responsive to signals telling the vessel to clamp down. The result is a spasm that temporarily chokes off blood flow, turning fingers white, then blue, then red as circulation returns. Unlike normal cold responses, these spasms are disproportionate to the temperature change and can be triggered by something as minor as reaching into a refrigerator.
Primary Raynaud’s: No Underlying Disease
The majority of people with Raynaud’s have the primary form, meaning no other medical condition is driving the vessel spasms. Primary Raynaud’s is essentially an amplified version of normal physiology, and researchers still don’t fully understand why some people’s blood vessels overreact so severely while others’ don’t.
Genetics likely play a role. About 30 percent of people who have a parent, sibling, or child with primary Raynaud’s develop it themselves, though no single gene has been pinpointed. Gene variations involved in blood vessel control may raise someone’s susceptibility, but the exact connection between those variations and the exaggerated constriction remains unclear. Women are affected more often than men, with prevalence estimates ranging from about 5 to 20 percent in women compared to 4 to 14 percent in men, depending on the population studied.
Secondary Raynaud’s: When Another Condition Is the Cause
Secondary Raynaud’s develops because of an identifiable underlying health problem, most often an autoimmune or connective tissue disease. The distinction matters because secondary Raynaud’s tends to be more severe and can lead to permanent tissue damage if the underlying condition isn’t managed.
Scleroderma is the most closely linked condition. The vast majority of people with scleroderma, a disease that causes hardening and scarring of skin and internal tissues, develop Raynaud’s symptoms. The disease damages blood vessel walls directly, causing them to thicken and narrow over time, which compounds the spasm problem. Other autoimmune conditions associated with secondary Raynaud’s include lupus, rheumatoid arthritis, and Sjögren syndrome. In these diseases, chronic inflammation gradually impairs the blood vessels’ ability to dilate properly.
One way doctors distinguish between the two forms is by examining the tiny blood vessels at the base of the fingernails using a specialized microscope. Abnormal capillary patterns at the nail fold are strong predictors that an autoimmune connective tissue disease is involved, pointing toward secondary rather than primary Raynaud’s.
Medications That Can Trigger Symptoms
Certain drugs cause or worsen Raynaud’s by narrowing blood vessels or interfering with circulation. Beta-blockers, a class of blood pressure medication, are a leading cause of drug-related Raynaud’s. ADHD stimulant medications have been associated with Raynaud’s symptoms in children. Even over-the-counter nasal decongestants containing pseudoephedrine can trigger episodes in the hands and feet by stimulating vessel constriction throughout the body.
Some cancer treatments carry significant risk. In studies of patients treated with certain chemotherapy combinations, more than one third developed Raynaud’s. The immunosuppressant cyclosporine, sometimes used for arthritis, is another known trigger. If you notice new or worsening cold sensitivity in your fingers after starting a medication, that connection is worth raising with your prescriber.
Occupational and Lifestyle Risk Factors
Regular use of vibrating hand tools, such as jackhammers, chainsaws, or grinders, can cause a form of secondary Raynaud’s known as vibration syndrome. The cumulative trauma from prolonged vibration directly damages the digital arteries and peripheral nerves in the hands. In studies of foundry workers, 31 percent of those exposed for less than a year and a half showed symptoms, rising to 71 percent among those exposed for more than three years. Advanced stages of damage have appeared after exposures as short as one year.
The early signs mirror Raynaud’s closely: tingling, numbness, and blanching of the fingers, especially when triggered by cold. With continued exposure, the damage can become irreversible as the blood vessels develop permanent structural narrowing. Smoking also contributes by constricting blood vessels and reducing peripheral circulation, making episodes more frequent and severe regardless of whether someone has primary or secondary Raynaud’s.
Cold and Stress as Triggers
While cold exposure is the most recognized trigger, emotional stress activates the same sympathetic nervous system pathway. The body’s fight-or-flight response releases norepinephrine, which constricts peripheral blood vessels just as cold does. For many people with Raynaud’s, anxiety, sudden emotional reactions, or even work-related pressure can provoke an episode without any temperature change at all. Over time, repeated spasms can cause the small blood vessels to thicken slightly, further restricting blood flow and making future episodes easier to trigger. This gradual structural change helps explain why some people find their symptoms worsen over years even when their overall health hasn’t changed.