Raynaud’s phenomenon is a paroxysmal spasm of the arteries, usually within the fingers, which is a hypersensitivity reaction of vessels to physical factors (cold, vibration), mental (emotional) or without cause. There is primary Raynaud’s phenomenon (idiopathic, called Raynaud’s disease) and secondary Raynaud’s phenomenon, which may precede the development of other diseases such as connective tissue diseases (Raynaud’s syndrome). Raynaud’s phenomenon should be differentiated from a natural reaction to cold occurring in acrocyanosis, painful erythema of the extremities (erythromelalgia), cyanosis and thromboembolic changes of the limbs. The prognosis in patients with Raynaud’s phenomenon is good. In about 10% of patients, symptoms completely disappear, and complications such as ulcers of fingertips are very rare. In patients with Raynaud’s syndrome prognosis depends on the course of disease. These subjects often have vascular complications of vasculitis and ulceration of fingertips.