Hyperhidrosis is a condition characterized by abnormally increased sweating, in excess of that required for regulation of body temperature. Although primarily a benign physical burden, hyperhidrosis can deteriorate quality of life from a psychological, emotional, and social perspective. In fact, hyperhidrosis almost always leads to psychological as well as physical and social consequences. People suffering from it present difficulties in the professional field, more than 80% experiencing a moderate to severe emotional impact from the disease and half are subject to depression.
This excess of sweat happens even if the person is not engaging in tasks that require muscular effort, and it does not depend on the exposure to heat. Common places to sweat can include underarms, face, neck, back, groin, feet, and hands. It has been called by some researchers 'the silent handicap'.
Both diaphoresis and hidrosis can mean either perspiration (in which sense they are synonymous with sweating) or excessive perspiration, in which case they refer to a specific, narrowly defined, clinical disorder.
Hyperhidrosis can either be generalized, or localized to specific parts of the body. Hands, feet, armpits, groin, and the facial area are among the most active regions of perspiration due to the high number of sweat glands (eccrine glands in particular) in these areas. When excessive sweating is localized (e.g. palms, soles, face, underarms, scalp) it is referred to as primary hyperhidrosis or focal hyperhidrosis. Excessive sweating involving the whole body is termed generalized hyperhidrosis or secondary hyperhidrosis. It is usually the result of some other, underlying condition.
Primary or focal hyperhidrosis may be further divided by the area affected, for instance, palmoplantar hyperhidrosis (symptomatic sweating of only the hands or feet) or gustatory hyperhidrosis (sweating of the face or chest a few moments after eating certain foods).
Hyperhidrosis can also be classified by onset, either congenital (present at birth) or acquired (beginning later in life).