Hyperhidrosis is a condition characterized by abnormally increased sweating in excess of that required for regulation of body temperature Although primarily a physical burden, hyperhidrosis can deteriorate quality of life from a psychological, emotional, and social perspective It has been called by some ‘the silent handicap’.
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.
The cause of primary hyperhidrosis is unknown, although some physicians who claim it is caused by over-activity of the sympathetic nervous system. Anxiety or excitement can exacerbate the condition for many sufferers. A common complaint of patients is they get nervous because they sweat, then sweat more because they are nervous. Other factors can play a role, including certain foods and drinks, nicotine, caffeine, and smells.
Injections of botulinum toxin type A can be used to block neural control of sweat glands. The effect can last from 3–9 months depending on the site of injections This use has been approved by the U.S. Food and Drug Administration (FDA) The duration of the beneficial effect in primary palmar hyperhidrosis has been found to increase with repetition of the injections The Botox injections tend to be painful. Various measures have been tried to minimize the pain, one of which is the application of ice.
BTX-A has since been approved for the treatment of severe primary axillary hyperhidrosis (excessive underarm sweating of unknown cause), which cannot be managed by topical agents
A microwave-based device has been tried for excessive underarm perspiration and appears to show promise.
Tap water Iontophoresis as a treatment for palmoplantar hyperhidrosis was originally described in the 1950s Studies showed positive results and good safety with tap water iontophoresis One trial found it decreased sweating by about 80%.