Raynaud's Disorder involves:

• A. Autoimmune vasospasms reducing blood flow to extremities.
• B. A bacterial infection of the skin.
• C. Overheating of the extremities.
• D. Permanent blood vessel occlusion.

Answer: (A)

Raynaud's involves episodes of abnormal, transient vasospasm in the small arteries of the fingers and toes, which sharply reduces blood flow during an attack. This vasospasm produces the characteristic coldness, numbness, and color changes as perfusion is briefly cut off and then restored. In many cases, especially the secondary form, autoimmune or connective tissue processes contribute to these vasospastic events, which is why an autoimmune component is often described in connection with Raynaud's. It is not an infection, not caused by overheating, and it does not involve a permanent blockage of the vessels—the reduced blood flow is temporary and reversible with the end of the vasospasm.