Apparatuses and methods for thermally treating sweat glands in a volume of skin of a patient. A unipolar RF handpiece comprises a unipolar RF electrode and a bipolar RF handpiece comprises a supply electrode and a ground electrode, separated by an insulator. The unipolar RF handpiece applies RF waves into the volume of skin to dielectrically heat the sweat glands and the bipolar RF handpiece introduces RF current dielectrically heat the sweat glands.In some embodiments, the electrodes of the bipolar RF handpiece are arranged coaxially and are adjustable to allow for adjusting the depth of the RF current. In some embodiments the RF waves are applied first, heating the sweat glands and thus increasing their water content so the RF current can be applied to complete thermal disruption or destruction of the sweat glands without disrupting surrounding tissue. In some embodiments, after the RF waves are applied, the RF current is applied to an upper part of the volume, thereby slowing conductive or convective cooling of the remainder of the volume below it.
