Raynaud’s phenomenon (RP) is also known as Raynaud’s syndrome. It is characterized by a triphasic reaction of pallor, grouping and flushing, mostly in the upper extremities, symmetrical on both sides, or involving the lower extremities, or both upper and lower extremities, and occasionally in the ears, nose, cheeks or collar. It is often triggered by cold or emotional excitement. During the attack, the fingers become cold, the skin is obviously pale and stiff, and even the fingers have difficulty moving, and there is a numbness and pins and needles sensation, then the color deepens to dark red or greenish purple, and in severe cases, some of the nails are also grouped, after which the skin color becomes lighter, diffuse flushing, and the throbbing sensation increases, and finally returns to normal. The repeated occurrence of Raynaud’s phenomenon can cause local ulceration, atrophy, sclerosis and gangrene. However, it is more common to see various nutritional changes in the fingers (toes), often with pointed or lemon shaped finger ends, and the nails can be twisted and deformed. Raynaud’s phenomenon can be divided into two kinds: primary and secondary. The former is of unknown etiology and is a benign spasm of the small arteries of the extremities, also known as Raynaud’s disease, mostly seen in women. The latter is secondary to other diseases, i.e. Raynaud’s phenomenon manifests in other diseases. Recent studies have shown that Raynaud’s phenomenon not only affects the extremities, but can also occur in the viscera of patients with connective tissue diseases, mainly involving the lungs, heart, brain, and kidneys, with varying reports as to whether Raynaud’s phenomenon can cause damage to internal organs. What can cause Raynaud’s syndrome? 1, idiopathic Raynaud’s syndrome cause is unknown, may be related to the following factors (1) cold stimulation: patients are more sensitive to cold stimulation, the incidence of the disease is higher in cold areas. (2) Nerve excitation: patients are mostly sympathetic excitation type, may be related to central nervous system dysfunction, sympathetic nerve hyperfunction. (3)Occupational factors:The incidence is up to 50% in workers who are engaged in long-term vibratory machinery, such as air hammer operators, and the specific mechanism is unknown. (4)Endocrine disorders:This disease accounts for 70% to 90% of women, the symptoms are aggravated during menstruation and alleviated during pregnancy, which may be related to sex hormones. (5) Other causes: genetics, fatigue, infection, etc. 2, secondary Raynaud’s syndrome is often associated with the following diseases (1) systemic scleroderma; (2) systemic lupus erythematosus; (3) dermatomyositis or polymyositis; (4) rheumatoid arthritis; (5) atherosclerosis of the extremities in patients over 50 years of age; (6) thrombotic vasculitis, rare; (7) primary pulmonary hypertension. Trauma and drugs such as ergot inducers, vincristine, and barbiturate can also cause this disease.