The two main causs of it are either over heating or stress bad nerves can also be the cause of it. Your doctor would be able to tell you for sure without any guess work.
Sweaty hands can be attributed to a glandular problem. Either you have too many sweat glands in your hands, or your sweat glands are over active. There are surgeries that can take care of the problem.
The main cause of sweaty hands is overactive sympathetic nervous system. It means that when maximum people would not sweat you will because your system responds to stimuli too easily.
