OVERVIEW

To understand Raynaud's syndrome, it's essential to first clarify what Raynaud's phenomenon is.

Raynaud's phenomenon refers to a condition where, upon exposure to cold or emotional stress (such as pressure or fright), the skin of the fingers or toes turns pale, bluish, and then red, accompanied by localized coldness, pain, or numbness. These symptoms typically resolve upon warming.

If Raynaud's phenomenon occurs independently without any evidence of underlying disease, it is termed primary Raynaud's phenomenon, often referred to as "Raynaud's disease" or "Raynaud's disorder."

If Raynaud's phenomenon is caused by other diseases (such as systemic lupus erythematosus, scleroderma, etc.), it is called secondary Raynaud's phenomenon, commonly known as "Raynaud's syndrome."

Raynaud's phenomenon is not uncommon in the general population. In fact, ordinary people may also experience cold skin and color changes in cold environments. However, those with Raynaud's phenomenon exhibit an "exaggerated" response to cold or emotional stimuli compared to others.

What is Raynaud's syndrome?

Raynaud's syndrome (i.e., the secondary Raynaud's phenomenon mentioned above) refers to a condition where, upon exposure to cold or emotional stress, the arteries—particularly the small arteries in the extremities—undergo intense constriction, leading to reduced blood flow. This results in skin color changes from pale to bluish, followed by redness.

Raynaud's syndrome is usually associated with identifiable underlying diseases or causes, such as rheumatoid arthritis, scleroderma, chemotherapy drugs, cryoglobulinemia, vibration-induced white finger, or carpal tunnel syndrome. These conditions or medications cause abnormal blood vessel responses in the extremities, triggering Raynaud's phenomenon.

SYMPTOMS

What are the typical manifestations of Raynaud's syndrome?

Patients often report a slow onset, initially occurring in winter with short durations, gradually progressing to episodes triggered by cold exposure or emotional stress. It typically affects both hands symmetrically, though toes may also be involved.

During episodes, the hands and feet become cold, numb, and occasionally painful. A classic attack usually presents with a clear boundary at the metacarpophalangeal joints, followed by fingers turning cold, pale, purple, and then red.

What happens if Raynaud's syndrome progresses?

In the advanced stages of Raynaud's syndrome, patients may gradually lose hair on the back of their fingers, experience slowed nail growth, roughness, deformation, thinning and tightening of the skin, and develop ulcers at the fingertips or around the nail bed, which may lead to infection.

What psychiatric symptoms might Raynaud's syndrome patients experience?

Patients with Raynaud's syndrome may exhibit symptoms of nervous system dysfunction, such as excitability, emotional impulsiveness, suspicion, depression, insomnia, and frequent dreaming.

Can Raynaud's syndrome affect vital organs like the heart, brain, or lungs?

Raynaud's syndrome is not limited to peripheral vasospasm; it may also involve pulmonary vasospasm, myocardial ischemia, reduced cerebral blood perfusion, and other ischemic conditions in critical organs. Symptoms like chest tightness, chest pain, dizziness, or even fainting may occur, potentially leading to secondary heart, lung, or brain disorders.

Therefore, in addition to monitoring limb symptoms, patients should also watch for any of the above abnormalities in vital organs like the heart, brain, and lungs.

CAUSES

What are the common causes of Raynaud's syndrome?

Common causes include:

• Autoimmune and connective tissue diseases: such as scleroderma, systemic lupus erythematosus, rheumatoid arthritis, mixed connective tissue disease, Sjögren's syndrome, and dermatomyositis.

• Chronic occlusive arterial diseases: such as peripheral atherosclerosis and thromboangiitis obliterans.

• Neurological disorders: such as POEMS syndrome.

• Drug-related factors: such as amphetamines and chemotherapy drugs (especially cisplatin and bleomycin).

• Occupational factors: such as hypothenar hammer syndrome, vibration disease, frostbite, and carpal tunnel syndrome.

• Blood disorders: such as cryoglobulinemia, cold agglutinin disease, paraproteinemia, and cryofibrinogenemia.

• Endocrine diseases: such as hypothyroidism.

Under what environmental factors can Raynaud's syndrome be triggered?

Cold temperatures, chilling of the limbs, emotional stress, agitation, smoking, and consuming spicy or cold foods can easily trigger Raynaud's syndrome. Patients should avoid these factors as much as possible in daily life.

Why do patients with Raynaud's syndrome experience skin pallor, cyanosis, and then flushing?

• Early pallor: Caused by spasms of the small arteries in the extremities (equivalent to shutting off the water supply), reducing blood flow to the skin and resulting in a pale appearance due to ischemia.
• Cyanosis after a few minutes: At this stage, the small arteries (water supply) begin to dilate, while the small veins (drainage) remain closed. The capillary network remains oxygen-deprived, causing the skin to appear bluish (like a rice field with water but still insufficient to irrigate the drought-stricken land).
• Subsequent flushing: When returning to a warm environment, the cold stimulus disappears, and the blood vessels in the extremities become congested, increasing local temperature and causing the skin to appear flushed. Once blood perfusion returns to normal, the skin color gradually normalizes.

Is Raynaud's syndrome hereditary?

Many patients with Raynaud's syndrome also have autoimmune diseases, most of which have a genetic component. Therefore, Raynaud's syndrome may also have a certain degree of heritability.

DIAGNOSIS

Does Raynaud's syndrome cause numbness and swelling in the hands after exposure to cold wind or playing in the snow during winter?

Under significant cold stimulation, most healthy individuals may experience symptoms similar to Raynaud's phenomenon, but recovery is usually quick.

If such symptoms occur frequently, last for a long time, and are particularly uncomfortable, it may indicate true Raynaud's phenomenon. In such cases, medical evaluation by a professional is necessary to determine whether Raynaud's disease or Raynaud's syndrome is present.

How can I easily check if I have Raynaud's phenomenon?

If typical symptoms occur, a cold water test can help assess the possibility of Raynaud's phenomenon. Immerse both hands in 4°C water for 1 minute and observe whether skin changes are triggered.

Alternatively, measure finger skin temperature at room temperature (20°C), then immerse the hands in 4°C water for 2 minutes and observe the recovery time. A recovery period exceeding 30 minutes is considered positive.

Of course, this is only a rough test. A definitive diagnosis requires specialized cold provocation testing in a medical setting.

What tests do doctors commonly use to diagnose Raynaud's phenomenon?

• Cold provocation test: After recording fingertip circulation waveforms using photoplethysmography, immerse the hands in cold water for 1 minute, dry them immediately, and then record fingertip circulation for 5 minutes. Healthy individuals typically recover to baseline levels within seconds, whereas patients with Raynaud's phenomenon take significantly longer, often exceeding 5 minutes.
• Local cooling test: At room temperature (20°C), measure finger skin temperature, then immerse the hands in 4°C water for 2 minutes. Observe the time taken for the skin temperature to return to baseline—recovery beyond 30 minutes is considered positive.
• Arm occlusion test: Place a blood pressure cuff on the upper arm, reduce pressure by 1.33 kPa from systolic blood pressure, and maintain for 5 minutes. After release, observe changes in finger skin color.
• Fist-clenching test: Clench both fists tightly for 1.5 minutes, then relax with elbows bent at waist level. This test may induce skin color changes and delay the recovery from pallor to normal.

What conditions are easily confused with Raynaud's phenomenon?

Due to similar clinical presentations, Raynaud's phenomenon should be differentiated from acrocyanosis, livedo reticularis, erythromelalgia, and frostbite.

How is Raynaud's syndrome distinguished from Raynaud's disease?

First, doctors conduct a detailed medical history and physical examination to identify potential underlying conditions causing Raynaud's syndrome.

Additional tests may include antinuclear antibodies, rheumatoid factor, immunoglobulin electrophoresis, complement levels, Coombs test, cryoglobulins, thyroid function, vascular ultrasound, and angiography.

If no specific underlying disease or medication is identified, the diagnosis is Raynaud's disease. If a clear cause is found, it is classified as Raynaud's syndrome.

Patients diagnosed with Raynaud's disease should undergo regular follow-ups, as an underlying condition may emerge over time, requiring reclassification as Raynaud's syndrome.

What are the distinguishing features of Raynaud's syndrome compared to Raynaud's disease?

Primary Raynaud's phenomenon (Raynaud's disease) is most common in young to middle-aged women (20–40 years old). The following characteristics suggest Raynaud's syndrome rather than Raynaud's disease:

• Onset later in life (over 40 years old);
• Male gender;
• Severe symptoms with signs of tissue ischemia, such as skin ulcers;
• Asymmetric hand involvement during episodes.

TREATMENT

Which department should patients with Raynaud's syndrome visit in the hospital?

If typical symptoms of Raynaud's syndrome appear, patients should seek medical attention at the rheumatology/immunology or vascular surgery department as early as possible to confirm the diagnosis and receive timely treatment.

Is there a possibility of curing Raynaud's syndrome?

Whether Raynaud's syndrome can be cured depends on whether the underlying disease causing it can be cured. With active treatment of the primary condition, Raynaud's syndrome usually improves accordingly.

Autoimmune diseases are common causes of Raynaud's syndrome, but they are often difficult to fully cure. Medications can only help maintain relative stability, so Raynaud's syndrome caused by autoimmune diseases is also challenging to completely cure.

However, avoiding cold exposure, emotional stress, quitting smoking, and other measures can reduce the frequency of Raynaud's syndrome episodes.

How is Raynaud's syndrome treated?

• First, actively treat the underlying disease causing Raynaud's syndrome. Treatment methods vary depending on the disease and will not be detailed here.
• Additionally, symptomatic treatment for Raynaud's syndrome itself can help alleviate discomfort. Main treatment methods include:
• Medication: Patients with mild symptoms may use oral or topical drugs under a doctor's guidance. Those unresponsive to oral/topical drugs or experiencing digital ischemia may require hospitalization and intravenous medications.
• Surgery: Severe cases with ineffective drug treatment and significant limb ischemia may require surgical interventions, such as sympathectomy.
• Other treatments: Such as plasma exchange.

When should patients with Raynaud's syndrome consider surgery?

Clinically, surgery may be considered if drug treatment at sufficient doses and duration fails, symptoms worsen and severely affect work/life, fingertip skin shows trophic changes, or arterial occlusive disease is present.

DIET & LIFESTYLE

What precautions should patients with Raynaud's syndrome take in daily life?

During winter, patients should keep their entire body warm and avoid exposing their limbs to cold environments. Maintain room temperature between 20–25°C. Avoid raw, cold, and spicy foods. Pay special attention to foot care, such as soaking feet in warm water to promote blood circulation.

Since hypertension and arteriosclerosis can cause cold extremities, avoid overexertion, excessive alcohol consumption, smoking, and overly salty foods. Additionally, manage stress and emotional agitation to maintain a positive mood.

What precautions should Raynaud's syndrome patients take at home?

• Keep room temperature between 22–23°C. Both patients and family members should actively quit smoking.
• Monitor the blood circulation in the patient's fingers/toes. If symptoms like paleness, pain, or numbness occur, soak in warm water and increase massage.
• If ulcers or gangrene develop on local skin, maintain cleanliness and use topical medications under a doctor’s guidance.
• Seek immediate medical attention if symptoms like fever, chills, or body aches occur.

PREVENTION

How to Reduce Raynaud's Syndrome Attacks?

• Avoid cold exposure as much as possible and keep your entire body warm. Wear gloves and thick socks in winter, and avoid moving directly from a hot environment into an air-conditioned room with very low temperatures in summer.
• Learn to manage stress and avoid extreme emotional fluctuations.
• Quit smoking.
• Try to avoid medications that trigger blood vessel constriction, such as decongestants, amphetamines, certain weight-loss drugs, and herbs containing ephedra. Also, avoid some migraine medications like sumatriptan or caffeine with ergotamine.
• If occupational factors are clearly responsible (e.g., prolonged use of vibrating tools in cold environments), try to change work conditions or environment.
• If possible, consider relocating to a warmer and drier climate.