Three separate times I have had just one finger cramp and hurt. An area slightly smaller than a dime at the base of my finger will turn bluish/purple. It appears to be a spasm of the arteriole. Just today I had another episode this time on the ball of the foot beneath the big toe. Four hours later and the area feels okay but it is colored reddish as if bruised, but it is not. I was not out in the cold but have been under a lot of stress.
Skin discoloration in the fingers and/or the toes after exposure to temperature changes or an emotional event is known as Raynaud's phenomenon. Color changes are the result of blood vessel spasm which decreases blood flow to the affected area. At first the area turns white from lack of blood, then it turns blue from lack of oxygen, and then it may turn red or "flushed" when the vessel reopens and blood flow returns. The cause of vasospasm is unknown, but likely related to abnormal nerve control of the blood vessel. Raynaud's phenomenon is more common in women over 20, and though it can be associated with other medical conditions or medications, it can also occur alone.
From what I have read about vasospasms you should see a doctor. Now if you have rheumatoid arthritis it is common to have spasms of contractions in your fingers and toes, due to swelling and infection attacking your ligaments. Go ahead and check with your doctor about this. Call his office and explain your concerns. If you are truly having vasospasms its important that you get that checked out soon. There also may be a simple reason for you having these problems, but you won't know until you get it checked out. Good luck and best wishes!
one finger stiff and cold about half the finger last joint pain for about one week what could it be