there are usually only two main underlying things that even really 'can" create actual 'numbness or sensory loss" in any given person, and one is possible nerve issues and the other would be loss of vascular flow from "something" possibly IN a vessel or compressing it from the outside? or even some inner compression possibly combined with a more outter structure like even a bone in the area?
but just having this bilaterally in both arms/hands would indicate a more of a 'centrally located" issue somewhere? more than likely either way, if this was either one, a c spine nerve/sensory issue or vascular too, it would kind of indicate that the main area would more than likely fall within that c spine level somewhere? just given the "where" in where its being affected in both of your hands at all?
i would most definitely see your doc for at least a basic neuro eval then see if he can send you for a 'contrasted' form of MRI which would also show the inner vascular structures using contrast at all with this type of MRI? there simply could be "something' that is up there that can be impacting/impinging the real bloodflow to certain areas depending upon you actually even lying ON that area of the problem that could easily impinge off a particular area of bloodflow in some way? the only reason i am leaning more towards the vascular vs what other possibles could simply also be there with your nerves but in a central way is the mere mention of the extremities actually feeling 'cold" vs a more norm body temp?
but either way, just obtaining that very basic baseline testing using the one good scan that can show both the nerves/nerve roots and down to that cord AND also the vascular structures with using that contrast along with having that c spine looked into too would be best looked at with MRI.
you just really DO NEED to find out what is behind this so it can simply be 'appropriately treated". guessing on this kind of stuff with any doc will not give YOU the best possible care here and thats why that one good type of MRI would seriously be the best way to simply 'look' into the base of operations so to speak? but DO see your doc. i wish you luck with this and hope whtever it is that is creating this is pretty basic and very treatable. please do keep us posted ww, FB