Hyperhidrosis means excessive sweating. It can be localised or affect the whole body. Sweating is controlled by the brain, which sends signals along nerves to the small sweat glands in the skin. Increased sweating is a normal response to a rise in body temperature, and to emotions such as anxiety. Hyperhidrosis can be idiopathic (unknown cause), due to diseased or irritated nerves, thyroid disorders, diabetes mellitus and occasionally as a side effect of certain medications such as antidepressants.
Visible sweat and wet clothes are what most patients experience, sometimes even during cool and calm situations. Sometimes, overgrowth of harmless skin bacteria can cause an unpleasant smell in patients with hyperhidrosis.