I know what you mean when a doctor blows you off...it happens to me all the time. If your toes and fingers turn dark red and purple, it could be a symptom of Raynaud's Disease, which is a problem with he blood vessels in your hands. I have this and I know how hard it is in the winter.
If your hands hurt in the cold, and turn white then red if you do not wear heavy gloves (like I wear) then you could have Raynaud's. If your doctor, he might not know about Raynaud's, because it is an autoimmune disease.
Also, sometimes feet and fingers turn red when bathing because of Scleroderma, another autoimmune disease.