The question is with reference to a patient suffering from differential body temperature, her right side (particularly the hand) occasionally being substantially colder than the left.
I agree with Ishag it normally is vascular in nature. That being said having carpel tunnel syndrome one of the symptoms is a decrease in temperature compared to the other hand.
If it is severe it could be Subclavian steal syndrome (SSS), also called subclavian steal phenomenon or subclavian steal steno-occlusive disease, is a constellation of signs and symptoms that arise from retrograde (reversed) blood flow in the vertebral artery or the internal thoracic artery, due to a proximal stenosis (narrowing) and/or occlusion of the subclavian artery. The arm may be supplied by blood flowing in a retrograde direction down the vertebral artery at the expense of the vertebrobasilar circulation. This is called the subclavian steal. It is more severe than typical vertebrobasilar insufficiency.
we see this kind of phenomenon not very rarely in patients with multiple sclerosis. the mechanism is thought to be damage to the intermediate horn that contains the nuclei of the sympathetic nerves. the sympathetic nerves determine the tone of the arterioles. therefore, very unusual phenomenon have been noted in patients with multiple sclerosis. they can have intermittent discoloration of the skin on one of the body, they can have sweating that is restricted to one arm or a leg and sometimes they can have half of their torso that is erythematous, mild edematous and xerodermia. if this patient does not have MS then you can look at the sympathetic chain dysfunction on the affected side. thanks.
Temperature of a part or organ depends upon vascularity. Highly vascular organs have a higher temperature than the surrounding structures. If the blood supply increases or decreases momentarily, the temperature changes accordingly.