Hi
Welcome to the MedHelp forum!
You have all the conditions that can hamper circulation—very cold climate, carpal tunnel, underactive thyroid and mitral valve prolapse. You need to consult a doctor to find out which one is causing more problems. Take care!
Narble made a good call.
Another possibility is a blood disorder, and you should consider a hematological work-up and microscopic examination of the blood cells. Sometimes ertythrocytes are produced that are too large to transit through the minute blood vessels in the extremities.
What you've described sounds similar to Reynauld's, a disease of peripheral circulation with signs and symptoms resembling your experience.
The suggestions caregiver222 gave are all good, though check to see if the supplements he suggested interact with any HRT or other meds you are on before trying them. I'd add wearing gloves if necessary to keep your hands warm.
A blue hand suggests circulatory deficiency. I wouldn't be too frightened,
If you are a smoker, stop smoking.
Slow-release niacin helps to open microcirculation. Hawthorne supplements also assist with microcirculation. 1000 mg a day of omega-3 fish oil will also help.
If it continues it might pay to have a color dopplar of the arm, just to make sure there is no arterial blockage.