Raynaud’s syndrome refers to paroxysmal spasms of the arteries in the extremities. It often develops under the influence of factors such as cold stimuli or emotional stress and is characterized by intermittent pale, cyanotic and flushed changes in the skin color of the extremities. There are two main types of Raynaud’s phenomenon. (i) secondary Raynaud’s phenomenon, such as patients with scleroderma or lupus; (ii) primary Raynaud’s phenomenon. The diagnostic criteria for primary Raynaud’s phenomenon: 1. episodes when cold or nervous; 2. symmetrical involvement of both hands; 3. normal pulse; 4. no or only superficial finger gangrene; 5. no corresponding other underlying disease; 6. symptoms for at least two years without other etiology. A proportion of primary Raynaud’s phenomenon also develops into systemic disease several years later.