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What is Raynaud's phenomenon is seen in -a)  SLEb)  Systemic sclerosisc)  DMd)  Hypertension and explain in detail?
Raynaud's phenomenon refers to episodic pallor of digits of the hands or feet. There is a typical sequence in change in colour from white, through blue, to red.
Skin discoloration occurs because an abnormal spasm of the blood vessels causes a diminished blood supply to the local tissues.
Initially, the digits involved turn white because of the diminished blood supply. The digits then turn blue because of prolonged lack of oxygen cyanosis develop. Finally, the blood vessels reopen, causing a local "flushing" phenomenon, which turns the digits red.
Most cases of Raynaud's phenomenon are primary, due to exaggerated vasomotor responses. There is no structural abnormality in the arterial wall, except later in course when thickening of intima is seen.
Secondary Raynaud's phenomenon is associated with SLE, systemic sclerosis, Atherosclerosis, Buerger's disease, RA.