In response to exposure to the cold, the body restricts blood flow to the skin to preserve its core temperature. People with Raynaud’s phenomenon (also called Raynaud’s syndrome) experience this restriction of blood flow more readily because of an enhanced sensitivity to cold. The areas of the body affected are typically the fingers and toes, although in rare cases Raynaud’s can affect the lips, nose, ear lobes, nipples, or tongue.^[1] The restriction of blood flow in people with Raynaud’s is also commonly triggered by emotional stress. Raynaud’s can be categorized as primary (without another underlying cause) or secondary (resulting from complications of another condition).^[2][3][4]

Raynaud’s phenomenon occurs when flares or “attacks” trigger blood vessels in certain parts of the body to constrict, reducing blood flow and causing pain, numbness, and tingling. The fingers and toes are the most common areas affected, but Raynaud’s can also affect the nose and ears.

During a Raynaud’s attack, loss of blood flow to the affected area causes the tissue to turn a pale white color. As blood in the area loses oxygen, the tissue becomes blue and feels cold and numb. When circulation is restored, the affected areas turn red and become swollen. People may also experience a tingling, burning, or throbbing sensation at this stage. Attacks can last from minutes to hours, but in rare cases Raynaud’s attacks can last for days, causing permanent damage to the affected areas.^[1][2]

Severe attacks, which are more common with secondary Raynaud’s phenomenon, can cause ulcers or sores to form on the end of the affected fingers or toes.

When Raynaud’s is suspected, a health care provider will consider risk factors such as the age of onset and location of the affected areas on the body and will evaluate the overall frequency and severity of symptoms. The person’s health history will also be reviewed for the presence of other symptoms that may indicate secondary Raynaud’s caused by another underlying condition.^[2]

A technique called nailfold capillary microscopy (NCM) may also be used to differentiate between primary and secondary Raynaud’s. NCM allows the physician to see changes in the structure of the capillaries that may indicate the presence of underlying conditions implicated in secondary Raynaud’s, such as scleroderma or other connective tissue disorders.^[5][6][7]

The main medical treatments for Raynaud’s are focused on reducing the severity and frequency of attacks and improving blood flow. Early treatments for Raynaud’s typically involve conservative therapies focused on lifestyle changes to avoid the circumstances that trigger attacks. This can include limiting cold exposure, avoiding stimulants such as caffeine^[8] or ADHD medications such as Ritalin (methylphenidate)^[9], and managing stress.

If conservative treatments fail, the following medications may be used to treat blood vessel constriction:

• Alpha-receptor blockers^[10]
• Phosphodiesterase inhibitors^[11]
• Calcium-channel blockers^[12]
• Endothelin-1 inhibitors^[13]
• Selective serotonin reuptake inhibitors (SSRIs)^[14]

Several supplements have been studied for Raynaud’s phenomenon.

• Pycnogenol: In a pilot trial comparing pycnogenol supplementation + standard therapy to standard therapy alone in women with primary Raynaud’s, pycnogenol supplementation significantly improved blood flow and reduced symptoms. Pycnogenol also improved tissue oxygen levels and reduced levels of biomarkers for oxidative stress.^[15]

• Fish oil: Fish oil was shown in one study to improve cold tolerance and delay blood vessel constriction in people with Raynaud’s.^[16]

• Essential fatty acids (omega-3 and omega-6): In a cohort of healthy participants, daily supplementation with an essential fatty acid (EFA) supplement for 6 months reduced red blood cell aggregation. Since red blood cell aggregation has been implicated in worsening blood flow to the affected extremities in people with secondary Raynaud’s, the authors speculated that EFA supplements and/or fish oil might be useful for treating Raynaud’s.^[17]

• Beetroot juice: Beetroot juice improved blood flow and blood vessel function and reduced inflammation in people with Raynaud’s.^[18]

Additional supplements studied for treating Raynaud’s include L-arginine and N-acetylcystine (NAC). However, neither L-arginine^[19][20] nor NAC^[21] supplementation were found to improve blood flow in people with Raynaud’s.

There haven’t been many studies specifically testing the effect of diets on Raynaud’s. However, some investigators have speculated that foods with circulation-improving properties such as garlic^[22] may help to improve blood flow. Additionally, foods that contain caffeine should be avoided, because it decreases blood flow to the extremities.^[23]

Some alternative, nonpharmaceutical interventions have been used to treat Raynaud’s, including exercise, therapeutic gloves, and laser therapy.^[24][25]

Acupuncture has also shown some modest benefits, although it remains to be seen whether it can cause a meaningful reduction in symptoms.^[26]

An older study found that immersing the hand in warm water then exposing it to cold increased finger temperatures in people with Raynaud’s,^[27] possibly through training the body’s natural ability to constrict and dilate blood vessels in response to environmental conditions.

The most common cause of Raynaud’s phenomenon is overactivation of the sympathetic nervous system. This causes an increased release of the neurotransmitter norepinephrine, which binds to and activates adrenergic receptors. When the alpha-2 adrenergic receptors on blood vessels are activated, the smooth muscle tissue that lines the blood vessel walls contracts, causing vasoconstriction (a narrowing of blood vessels).

Excessive blood vessel constriction reduces blood flow to the extremities, which causes the characteristic changes in skin color associated with Raynaud’s as well as pain, tingling, and numbness.

There are two main variants of Raynaud’s: primary and secondary. With primary Raynaud’s, the disorder occurs on its own, independent of any underlying condition. In contrast, secondary Raynaud’s is caused by the presence of another underlying condition, such as lupus, scleroderma, or other autoimmune disorders.^[2]