Raynauds phenomenon or syndrome (RS) is an episodic attacks of transient digital ischemia resulting from vasospasm of the digital artery, precapillary arterioles, and skin arteriovenous shunts in response to exposure to cold temperature or emotional stress. Prevalence averages 35%. The high prevalence of RS in the population, as well as the frequent association with other, often life-threatening, diseases and conditions, determines its clinical significance. In 8090% of cases, RS is idiopathic. It is assumed that the spasmodic reactivity of the vessels is caused by a violation of the central and local dysregulation of vascular tone. The most important role is played by vascular endothelial, intravascular and neuronal disorders.
In at least 10% of cases, this is a secondary phenomenon. Most often, RS is associated with systemic rheumatic diseases. Along with this, endocrine diseases can develop, including those affected by the pituitary, thyroid and parathyroid glands, adrenal glands, and diabetes mellitus. In some cases, RS may be the only symptom of endocrine pathology. In general, SR is a condition with a favorable outlook and a stable course. The most informative instrumental method for the differential diagnosis of primary and secondary syndrome is the capillaroscopy of the nail bed.