Decreased blood flow
A person with on and off cold fingers and/or toes usually has occasional decreased blood flow to his hands/feet.
This is not from blood clots, but is due to the temporary contraction
of little arteries carrying blood to the hands/feet. The arteries relax and widen later, and the hands/feet warm up again. A primary care doctor or rheumatologist can evaluate, as it could be an autoimmune disorder.