Raynaud’s phenomenon is caused by exaggerated spasms in the small blood vessels of your fingers and toes, temporarily cutting off blood flow when you’re exposed to cold or emotional stress. About 5% of the general population experiences it, and in 80 to 90% of cases there’s no identifiable underlying disease. For the remaining 10 to 20%, the vasospasm is triggered or worsened by an autoimmune condition, certain medications, or repetitive physical trauma to the hands.
How the Vasospasm Works
Everyone’s blood vessels narrow in response to cold. That’s normal. It redirects warm blood toward your core to protect vital organs. In Raynaud’s, this response is dramatically amplified, and the mechanism centers on a specific receptor found in the smooth muscle cells lining the tiny arteries of your skin.
When temperature drops, the energy-producing structures inside those muscle cells detect the change and release signaling molecules that set off a chain reaction. Within minutes, this chain reaction physically moves receptors from deep inside the cell to its surface. Once those receptors reach the surface, they interact with norepinephrine, a stress hormone your body naturally releases, and trigger intense constriction. In people with Raynaud’s, this receptor mobilization is excessive. Research published in Frontiers in Pharmacology confirmed that the entirety of cold-induced constriction in skin arteries is driven by this single receptor type, known as the alpha-2C adrenergic receptor. The more receptors that reach the cell surface, the stronger the constriction and the more complete the blood flow shutdown.
This is why attacks follow a classic color sequence: fingers turn white as blood flow stops, then blue as trapped blood loses oxygen, and finally red as vessels reopen and blood rushes back in. The whole episode can last anywhere from a few minutes to over an hour.
Primary Raynaud’s: No Underlying Disease
The vast majority of people with Raynaud’s have the primary form, meaning their blood vessels simply overreact to cold or stress without any other disease driving it. Primary Raynaud’s typically appears between ages 15 and 30 and is more common in women. Attacks are usually mild, affect both hands symmetrically, and don’t cause lasting tissue damage.
The exact reason some people develop this heightened vascular sensitivity isn’t fully understood, but hormones play a measurable role. A study of postmenopausal women found that those taking estrogen alone had 2.5 times the odds of developing Raynaud’s compared to women not on hormone therapy. Interestingly, women taking estrogen combined with progesterone showed no increased risk at all, with prevalence nearly identical to nonusers (9.8% versus 8.4%). Experimental studies support this, showing that estrogen increases the constriction response in blood vessels, while progesterone counteracts that effect. This hormonal connection helps explain why Raynaud’s disproportionately affects women, particularly during reproductive years when estrogen levels fluctuate.
Secondary Raynaud’s: When Another Condition Is Involved
Secondary Raynaud’s develops as a consequence of another disease, and the attacks tend to be more severe. They may affect one hand more than the other, cause painful ulcers on fingertips, and begin later in life, often after age 30.
The conditions most commonly linked to secondary Raynaud’s are autoimmune and connective tissue diseases. Scleroderma has the strongest association. The disease thickens and hardens skin and blood vessel walls, making vessels far more prone to spasm. Lupus, Sjögren syndrome, rheumatoid arthritis, and polymyositis are also well-established causes. In many cases, Raynaud’s is the very first symptom of these diseases, appearing months or even years before other signs develop.
Other medical conditions that can trigger secondary Raynaud’s include blood disorders that make blood thicker or stickier, thyroid disorders, pulmonary hypertension, and atherosclerosis (plaque buildup that narrows arteries). Because the list of possible underlying causes is broad, new-onset Raynaud’s in someone over 30, especially with asymmetric attacks or fingertip sores, typically warrants blood tests to check for autoimmune markers.
Medications That Can Trigger Attacks
A surprisingly wide range of drugs can cause or worsen Raynaud’s. A systematic review identified 12 distinct drug classes capable of triggering vasospasm, each through a different mechanism.
- Beta-blockers, commonly prescribed for high blood pressure and anxiety, are one of the longest-recognized culprits. They block receptors that help blood vessels relax, tipping the balance toward constriction.
- ADHD stimulants like methylphenidate and dextroamphetamine have a significant association with Raynaud’s in children. A case-control study of 64 children found a clear link between past or current stimulant use and the development of Raynaud’s. These drugs boost the release of stress hormones that drive vessel constriction.
- Certain chemotherapy agents, particularly cisplatin and bleomycin, carry the highest risk of drug-induced Raynaud’s among all medication classes. The vasospasm can persist even after treatment ends.
- Interferons, used for hepatitis and some cancers, cause Raynaud’s in an estimated 13.6% of patients who take them.
- Migraine medications containing ergot compounds and some newer targeted cancer therapies (tyrosine kinase inhibitors) round out the list.
If you notice Raynaud’s symptoms appearing shortly after starting a new medication, that timing is worth mentioning to your prescriber. In many cases, switching to an alternative drug resolves the problem.
Vibration and Occupational Exposure
Repeated use of vibrating hand tools is a well-documented cause of secondary Raynaud’s, sometimes called vibration white finger. Pneumatic hammers, chain saws, grinders, and pavement breakers are among the most common offenders. The vibration damages the small blood vessels and nerves in the hands over time, eventually producing the same vasospastic attacks seen in other forms of Raynaud’s.
The risk increases directly with years of exposure. A NIOSH study of foundry and shipyard workers found that 31% of those exposed for 18 months or less developed significant symptoms. That number rose to 41% at one to three years and 71% beyond three years. In some cases, advanced symptoms appeared after just one year of exposure. Foundry workers developed blanching attacks after an average of 2 years, while shipyard workers, who used different tools, took an average of 17 years. The difference reflects both the type of tool and the intensity of vibration.
Cold, Stress, and Other Everyday Triggers
Cold exposure is the most obvious trigger, but it doesn’t have to be extreme. Reaching into a freezer, holding a cold drink, or walking into an air-conditioned building can set off an attack. Dampness amplifies the effect: cold, wet conditions are more provocative than cold, dry ones. Even localized pressure on the hands, like gripping grocery bags, has been documented as a trigger in people already prone to vasospasm.
Emotional stress triggers attacks through the same pathway as cold. Your body releases norepinephrine during the stress response, and in someone with Raynaud’s, those already-primed receptors on the blood vessel surface respond with disproportionate constriction. This is why some people experience attacks during arguments, exams, or high-pressure work situations even in a warm room.
Smoking compounds the problem by damaging blood vessel walls and further constricting small arteries. Caffeine can also provoke mild vasoconstriction, though its effect varies widely between individuals. For people with frequent attacks, identifying personal trigger patterns is often more useful than memorizing a list, since sensitivity thresholds differ from person to person.