The causes need to be considered for it are;
1) Nerves; pinched nerves in neck and back can cause sensitive feet and palms and cold/numb finger tips.
2) Arteries; Early atherosclerosis or capillaries affection due to autoimmune phenomenon.
3) Deficiency disorder like Vitamin B12.
Out of them pinched nerves in neck and back are the most common. Physical therapy is the treatment.
Investigations advised for your symptoms are;
1) Electromyography/nerve conduction studies (EMG/NCS)
2) MRI of the spine and brain
3) blood glucose, glucose tolerance test and glycosylated hemoglobin
4) serum B12 level with methylmalonic acid (with or without homocysteine),
5) serum protein electrophoresis
6) Anti-nuclear antibody
7) Lyme testing
8) Rheumatoid factor
9) Sjogren's syndrome testing (Anti-Ro, Anti-La Antibodies)
Skin and nerve biopsy are recommended after the results of these investigations.
This should give the diagnosis and guidelines for the management.
Please feel free for your follow up questions.
I would be happy to assist you further, if you need any more information.
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