Hyperhidrosis is the condition characterized by abnormally increased sweating/perspiration,[1] in excess of that required for regulation of body temperature. It is associated with a significant quality of life burden from a psychological, emotional, and social perspective. As such, it has been referred to as the 'silent handicap'.

Hyperhidrosis can either be generalized or localized to specific parts of the body. Hands, feet, armpits, and the groin area are among the most active regions of perspiration due to the relatively high concentration of sweat glands. When excessive sweating is localized (e.g. palms, soles, face, underarms, scalp) it is referred to as primary or focal hyperhidrosis. Generalized or secondary hyperhidrosis usually involves the body as a whole and is the result of an underlying condition.
Hyperhidrosis can also be classified depending by onset, either congenital or acquired. Focal hyperhidrosis is found to start during adolescence or even before and seems to be inherited as an autosomal dominant genetic trait. Primary or focal hyperhidrosis must be distinguished from secondary hyperhidrosis, which can start at any point in life. The latter form may be due to a disorder of the thyroid or pituitary glands, diabetes mellitus, tumors, gout, menopause, certain drugs, or mercury poisoning.[citation needed]
Hyperhidrosis may also be divided into palmoplantar (symptomatic sweating of primarily the hands or feet), gustatory, generalized and focal hyperhidrosis.[1]
Alternatively, hyperhidrosis may be classified according to the amount of skin affected and its possible causes.[4] In this approach, excessive sweating in an area greater than 100 cm2 (16 sq in) (up to generalized sweating of the entire body) is differentiated from sweating that affects only a small area.[citation needed]
Cause[edit]

Further information: Diaphoresis
The cause of primary hyperhidrosis is unknown, although some surgeons[who?] claim it is caused by sympathetic over-activity. Nervousness or excitement can exacerbate the situation for many sufferers. Other factors can play a role; certain foods and drinks, nicotine, caffeine, and smells can trigger a response.
A common complaint of patients is they get nervous because they sweat, then sweat more because they are nervous.
Hyperhidrosis of a relatively large area (generalized; over 100 cm2)
In people with a past history of spinal cord injuries
Autonomic dysreflexia
Orthostatic hypotension
Posttraumatic syringomyelia
Associated with peripheral neuropathies
Familial dysautonomia (Riley-Day syndrome)
Congenital autonomic dysfunction with universal pain loss
Exposure to cold, notably associated with cold-induced sweating syndrome
Associated with probable brain lesions
Episodic with hypothermia (Hines and Bannick syndrome)
Episodic without hypothermia
Olfactory
Associated with intrathoracic neoplasms or lesions
Associated with systemic medical problems
Pheochromocytoma
Parkinson's disease
Thyrotoxicosis
Diabetes mellitus
Congestive heart failure
Anxiety
Menopausal state
Due to drugs or poisoning
Night sweats
Compensatory
Associated with toxins[citation needed]
Infantile acrodynia induced by chronic low-dose mercury exposure, leading to elevated catecholamine accumulation and resulting in a clinical picture resembling pheochromocytoma.[citation needed]
Hyperhidrosis of relatively small area (less than 100 cm2)
Idiopathic unilateral circumscribed hyperhydrosis
Reported association with:
Blue rubber bleb nevus
Glomus tumor
POEMS syndrome
Burning feet syndrome (Goplan's)
Trench foot
Causalgia
Pachydermoperiostosis
Pretibial myxedema
Gustatory sweating associated with:
Encephalitis
Syringomyelia
Diabetic neuropathies
Herpes zoster (shingles)
Parotitis
Parotid abscesses
Thoracic sympathectomy
Auriculotemporal or Frey's syndrome
Miscellaneous
Lacrimal sweating (due to postganglionic sympathetic deficit, often seen in Raeder's syndrome)
Harlequin syndrome
Emotional hyperhidrosis
Treatment[edit]

Medications[edit]
Aluminium chloride is used in regular antiperspirants. However, hyperhydrosis sufferers need solutions or gels with a much higher concentration to effectively treat the symptoms of the condition. These antiperspirant solutions or hyperhydrosis gels are especially effective for treatment of axillary or underarm regions. Normally it takes around three to five days to see the results. The main secondary effect is irritation of the skin. For severe cases of plantar and palmar hyperhydrosis, there is some success using conservative measures such as higher strength aluminium chloride antiperspirants.[5] The Canadian Hyperhidrosis Advisory Committee has published treatment guidelines for focal hyperhidrosis based on evidence based clinical support. It recommends an aluminium chloride hexahydrate salicylic acid gel as initial treatment for axillary, plantar and palmar hyperhidrosis
Injections of botulinum toxin type A, (Botox, Dysport) are used to block neural control of sweat glands.[5][6] The effects can last from 3–9 months depending on the site of injections.[7] This procedure used for underarm sweating has been approved by the U.S. Food and Drug Administration (FDA).[8]
Several anticholinergic drugs reduce hyperhidrosis. Oxybutynin (brand name Ditropan) is one that has shown promise,[5][9] although it has important side effects, which include drowsiness, visual symptoms and dryness in the mouth and other mucous membranes. A time release version of the drug is also available (Ditropan XL), with purportedly reduced effectiveness. Glycopyrrolate (Robinul) is another drug used on an off-label basis. The drug seems to be almost as effective as oxybutynin and has similar side-effects. Other anticholinergic agents that have tried to include propantheline bromide (Probanthine) and benztropine (Cogentin).[citation needed]
Surgical procedures[edit]
Sweat gland removal or destruction is one surgical option available for axillary hyperhydrosis. There are multiple methods for sweat gland removal or destruction such as sweat gland suction, retrodermal currettage, and axillary liposuction, Vaser, or Laser Sweat Ablation. Sweat gland suction is a technique adapted from liposuction.[10]
The other main surgical option is endoscopic thoracic sympathectomy (ETS), which cuts, burns, or clamps the thoracic ganglion on the main sympathetic chain that runs alongside the spine. Clamping is intended to permit the reversal of the procedure. ETS is generally considered a "safe, reproducible, and effective procedure and most patients are satisfied with the results of the surgery".[11] Satisfaction rates above 80% have been reported, and are higher for children.[12][13] The procedure causes relief of excessive hand sweating in about 85-95% of patients.[14] ETS may be helpful in treating axillary hyperhidrosis, facial blushing and facial sweating; however, patients with facial blushing and/or excessive facial sweating experience higher failure rates, and patients may be more likely to experience unwanted side effects.[15]
ETS side effects have been described as ranging from trivial to devastating.[16] The most common secondary effect of ETS is compensatory sweating, sweating in different areas than prior to the surgery. Major drawbacks related to compensatory sweating are seen in 20–80%.[17][18][19] Most people find the compensatory sweating to be tolerable while 1–51% claim that their quality of life decreased as a result of compensatory sweating."[12] Total body perspiration in response to heat has been reported to increase after sympathectomy.[20]
Additionally, the original sweating problem may recur due to nerve regeneration, sometimes within 6 months of the procedure.[17][18][21]
Other side effects include Horner's Syndrome (about 1%), gustatory sweating (less than 25%) and on occasion very dry hands (sandpaper hands).[22] Some patients have also been shown to experience a cardiac sympathetic denervation, which results in a 10% lowered heartbeat during both rest and exercise; leading to an impairment of the heart rate to workload relationship.[23]
Lumbar sympathectomy is a relatively new procedure aimed at those patients for whom endoscopic thoracic sympathectomy has not relieved excessive plantar (foot) sweating. With this procedure the sympathetic chain in the lumbar region is clipped or divided in order to relieve the severe or excessive foot sweating. The success rate is about 97% and the operation should be carried out only if patients first have tried other conservative measures.[24] This type of sympathectomy is no longer considered controversial in regards to hypotension and retrograde ejaculation.[25][26] The development of retrograde ejaculation, inability to maintain erection and hypertension as a result of this surgery appears to be rare to non-existent; journal articles describing the technique and case reports suggest that none of 18 men undergoing the procedure at two separate surgical units experienced sexual disability following surgery, while no mention is made of hypertension or sexual disabilities occurring in female patients.[25][26]
Percutaneous sympathectomy is a related minimally invasive procedure similar to the botulinum method, in which the nerve is blocked by an injection of phenol.[27] The procedure allows for temporary relief in most cases. Some medical professionals advocate the use of this more conservative procedure before the permanent surgical sympathectomy.
Non-surgical treatments[edit]
Iontophoresis was originally described in the 1950s, although the exact mode of action remains elusive.[28] The affected area is placed in a device that has two pails of water with a conductor in each one. The hand or foot acts like a conductor between the positively- and negatively-charged pails. As the low current passes through the area, the minerals in the water clog the sweat glands, limiting the amount of sweat released. Some people[who?] have seen great results while others[who?] see no effect. The device can be painful (pain is usually limited to small wounds and over time the body adjusts to the procedure) and the process is time-consuming. The device is usually used for the hands and feet, but there has been a device[clarification needed] created for the axillae (armpit) area and for the stump region of amputees.[citation needed]
Prognosis and impact[edit]

Hyperhidrosis can have physiological consequences such as cold and clammy hands, dehydration, and skin infections secondary to maceration of the skin. Hyperhidrosis can also have devastating emotional effects on one’s individual life.[citation needed]
Affected people are constantly aware of their condition and try to modify their lifestyle to accommodate this problem. This can be disabling in professional, academic and social life, causing embarrassments. Many routine tasks become impossible chores, which can psychologically drain these individuals.[citation needed]
Excessive sweating or focal hyperhidrosis of the hands interferes with many routine activities,[29] such as securely grasping objects. Some focal hyperhidrosis sufferers avoid situations where they will come into physical contact with others, such as greeting a person with a handshake. Hiding embarrassing sweat spots under the armpits limits the sufferers' arm movements and pose. In severe cases, shirts must be changed several times during the day. Additionally, anxiety caused by self-consciousness to the sweating may aggravate the sweating. Excessive sweating of the feet makes it harder for patients to wear slide-on or open-toe shoes, as the feet slide around in the shoe because of sweat.[citation needed]
Some careers present challenges for hyperhidrosis sufferers. For example, careers that require the deft use of a knife may not be safely performed by people with excessive sweating of the hands. The risk of dehydration can limit the ability of some sufferers to function in extremely hot (especially if also humid) conditions.[30] Even the playing of musical instruments can be uncomfortable or difficult because of sweaty hands.[citation needed]
Epidemiology[edit]

Focal hyperhidrosis is estimated at 2.8% of the population of the United States.[29] It affects men and women equally, and most commonly occurs among people aged 25–64 years. Some may have been affected since early childhood.[29] About 30–50% have another family member afflicted, implying a genetic predisposition.[29]
In 2006, researchers of Saga University in Japan reported that primary palmar hyperhidrosis locus maps to 14q11.2–q13.[31]