Hyperhidrosis means excessive sweating. Perspiration is a normal bodily function, controlled by the autonomic nervous system. Sweat glands are found in the skin throughout the body, however are present in higher numbers in the skin of the hands, feet, armpits and the genital regions. Perspiring is a normal physiologic response of the body when the internal or body temperature rises. This response is characteristically seen with either exercise, or exposure to high environmental temperatures. Stressful situations can also stimulate the autonomic nervous system which then increases sweat production by the glands highly concentrated in the hands, feet, or other regions. In most people, the autonomic response in the sweat glands to stress is not excessive. Unfortunately in patients with hyperhidrosis, the autonomic stimulation of the sweat glands in response to stress is hyperactive. Normal everyday encounters, such as taking notes in school, holding or shaking someone's hand are embarrassing. Yet the physiologic response of the autonomic nervous system to exercise or high temperature is normal.

It is estimated that approximately 1% of adults suffer from hyperhidrosis. Typically excessive sweating begins in childhood or early adolescence and increases in severity through puberty and into adulthood. Men and women are equally affected. In many patients, the symptoms are mild, and not socially disabling. Symptoms usually appear during adolescence and either remain mild, or gradually progress into adulthood, rarely diminishing spontaneously. Palmar hyperhidrosis, or sweaty palms is the most common manifestation, and the most socially disturbing. Sufferers fear any situation which may require hand contact. This impacts on one's ability to interact effectively in the work place, and can have devastating effects on one's social interaction with the opposite sex.

Many patients can simultaneously experience plantar hyperhidrosis (soles of feet), axillary (arm pits) hyperhidrosis, or facial blushing. The different combinations of symptoms can vary between individuals, however, the palmar sweating is the most difficult to control and is the most troubling.