All the skin on your palm, soles of your feet and in fact all the non-mucosal covered skin on your body is dead on the top few layers. If the skin is particularly thick, it is a callous and you should see a dermatologist.
Anything from an allergic reaction to a fungal infection. Your hands touch nearly every object you come into contact with and are often the first to have a reaction.
If you've already ruled out excema then it could be an allergic reaction to something you are touching such as latex gloves or even your car stick shift.
