In short, hyperhidrosis is excessive sweating. Usually of the hands, underarms and other areas of the body. The keyword is excessive. If there is no underlying medical issues, it is generally considered to be hereditary or genetic condition. I have hyperhidrosis of the head. Long before I start sweating elsewhere, I will sweat from my head. My mother had this condition. It is not life threatening, but it is embarrassing and very inconvenient. For this reason I do not wear hats or cover my head. Only during cold, Winter weather will I cover my head. If I’m working hard like shoveling snow, I do not want to cover my head or else I start sweating “like a pig”.