Why do my fingertips and palms become sweaty when I hold a highlighter?

[Defenestrator]

I wish to start using a Sharpie highlighter while reading through my course work. However, a curious phenomenon occurs when I do so; the fingertips and palms of both of my hands become slightly moistened, creating a feeling of discomfort.

I actually, just now, tried wrapping duct tape around the shaft of the highlighter. After washing my hands, the uncomfortable moistness returned.