Background
Raynaud phenomenon (RP) was first described by Maurice Raynaud in 1862 and refers to a transient vasospasm of peripheral arteries and arterioles that classically results in triphasic color changes in the affected region.
The initial artery and arteriole vasospasm causes pallor (white), followed by cyanosis (blue) due to dilation of the capillaries and venous stasis (deoxygenated blood), with continued artery and arteriole vasospasm. The arteries and arterioles then dilate, causing rapid return of blood flow (red, reactive hyperemia).
The fingers are the most commonly affected region, and Raynaud phenomenon is typically triggered by cold exposure or stress.
See the image below.
Raynaud phenomenon showing demarcation of color difference.
Raynaud phenomenon can be primary (idiopathic), meaning no associated diseases are present (about 80-90% of cases), or secondary, meaning that another condition is believed to be the cause of the Raynaud phenomenon.
Connective tissue diseases are the most common cause of secondary Raynaud phenomenon, but several medications and many other conditions are also associated with Raynaud phenomenon.
In the past, Raynaud phenomenon had been referred to as Raynaud syndrome, with Raynaud disease referring to primary Raynaud phenomenon, and Raynaud phenomenon referring to secondary Raynaud phenomenon; however, these terms were often used interchangeably.
The current preferred terminology of primary and secondary Raynaud phenomenon was proposed by LeRoy and Medsger in 1992.
Primary Raynaud phenomenon rarely leads to significant problems and does not usually need to be treated with medications. In contrast, secondary Raynaud phenomenon, especially when associated with scleroderma-related diseases, often causes irreversible digital ischemia, resulting in the development of digital ulcers or even digital amputation.