Hyperhidrosis is excessive sweating that may occur over the entire body or only in certain parts, most commonly the face, underarms, palms of the hands and soles of the feet. It may also refer to severe facial blushing.
This condition is caused by overactivity of the nerves that carry messages to the affected sweat glands. These nerves are part of the 'sympathetic' nervous system, which means that they are 'involuntary' or not under our conscious control.
Treatment may be with medication or, for facial and palm sweating, may involve a surgical procedure known as Endoscopic Thoracic Sympathectomy (ETS). Surgery is usually only offered if medication has failed and the sweating interferes with your daily functioning.

The surgery is a minimally invasive procedure (it does not require a large incision or cut to be made) and involves interrupting the nerves that supply the sweat glands.