Triphasic color response of Raynauds Phenomenon and what is the pathophysiology of each phase
The sequential color changes of RP are white to blue to red. Initial digital artery vasospasm causes a pallor (blanching) of the digit, which gives way to cyanosis as static venous blood deoxygenates. With rewarming, the ischemic phase lasts 15 to 20 minutes followed by reactive hyperemia which causes the final stage, rubor. The classic triad in the classic order may not be seen in all patients. Pallor is the most definitive phase.