Raynaud's phenomenon

RP is a vasospastic disorder that results in characteristic, triphasic changes in skin color occurring in response to various external triggers, including exposure to cold.

RP may be idiopathic in origin (primary RP), or occur in the context of connective tissue diseases (secondary RP), such as systemic sclerosis, dermatomyositis, SLE, Sjögren's syndrome, mixed connective tissue disease, or undifferentiated connective tissue disease.

In the US, the prevalence of primary RP is estimated at 4.85% (95% CI, 2.08-8.71%), while the pooled annual incidence is estimated at 0.25% (95% CI, 0.19-0.32%).

In patients with RP, exposure to cold triggers intense sympathetic vasoconstriction in skin areas bearing specialized arterio-venous anastomoses that normally contribute to thermoregulation (fingers, toes, nose, and ear tip). In patients with secondary RP, abnormal endothelial function increases the risk of ischemic complications.

Severe disease may progress to digital ulcerations, necrosis, and self-amputation.