- What is Focal Hyperhidrosis?
- Risk Factors
- Clinical Examination
- How is it Diagnosed
What is Focal Hyperhidrosis?
Hyperhidrosis is a condition characterised by excessive perspiration. Unlike normal sweating which occurs as a thermoregulatory response (that is, in response to temperature stimuli in an attempt to maintain the body’s normal temperature), the excessive sweating characterising hyperhidrosis occurs due to a non-thermoregulatory response. The condition was first described about a century ago, but only recently has hyperhidrosis and its treatments received widespread attention. While there are many definitions, the condition may be described as sweating more than is required to regulate the body temperature.
This condition is of particular interest in Australia presently because as of December 1st, 2011, one of the treatment options (botulinum toxin) has been listed on the Pharmaceutical Benefits Scheme (PBS), making this treatment more accessible and affordable to those with the axillary form (see below).
Hyperhidrosis may affect the entire body in which case it is referred to as generalised hyperhidrosis. Generalised hyperhidrosis usually occurs as a result of a medical condition. It is quite important that your doctor or specialist screens for these conditions.
When excessive sweating occurs at one or more distinct body sites (e.g. the armpits or face, but not the entire body) it is referred to as focal hyperhidrosis. It is also known as primary or essential hyperhidrosis, as it occurs in the absence of any apparent cause and typically affects otherwise healthy individuals. However, even generalised hyperhidrosis, which can be secondary, can appear to mainly affect areas most involved in focal hyperhidrosis.
Focal hyperhidrosis can be further classified according to the body site affected:
- Palmar hyperhidrosis: Affects the hands. 25% of all individuals with focal hyperhidrosis experience excessive sweating on the hands;
- Axillary hyperhidrosis: Affects the armpits. The armpits are affected in 51% of individuals with the condition;
- Plantar hyperhidrosis (also known as pedal hyperhidrosis): Affects the feet, and is reported in 29% of individuals with focal hyperhidrosis; or
- Craniofacial hyperhidrosis: Affects the face, and is reported in 20% of affected individuals.
In focal hyperhidrosis, several body sites may be affected. For example, palmar–plantar hyperhidrosis affects the hands and feet, while palmar–axillary hyperhidrosis affects the hands and armpits. While it is typically idiopathic (occurring without known cause), focal hyperhidrosis can also occur secondary to a medical condition or medication use.
Sweat is secreted by sweat glands, normally as a thermoregulatory response. No changes to the sweat glands (e.g. increased quantity or size) are observed in individuals with focal hyperhidrosis, so the condition is hypothesised to arise due to overactivity of the sympathetic nervous system (the section of the nervous system that regulates involuntary muscle movements), which sends the signals to the sweat glands to trigger sweating. Other neurological pathways (pathways of the nervous system) involving the cerebral cortex (an area of the brain that processes complex information and regulates voluntary movement) and hypothalamus (a hormone-producing gland in the brain) are also thought to play a role in hyperhidrosis, as is the parasympathetic nervous system.
|For more information on the anatomy and physiology of sweating, see Sweating (Perspiration).|
Focal hyperhidrosis is falsely perceived to be a rare condition. A large US study reported that 2.8% of the general population experience focal hyperhidrosis.Men and women are equally affected. About one-sixth of those affected by the condition (0.5% of the general population) report hyperhidrosis being intolerable or interfering with their daily activities.
Focal hyperhidrosis is most prevalent in 25–64 year olds. The average age of onset is 26 years, though it differs according to the body site affected. Palmar and axillary hyperhidrosis typically have an earlier onset, occurring at 13 and 19 years respectively.
There are significant geographic differences in prevalence. For example, palmar hyperhidrosis, thought to affect 0.61% of the population in developed countries, is much more common in other geographic populations (e.g. 3% of the south Asian population is severely affected by the condition).
Focal hyperhidrosis is a heritable condition and family history is the only factor known to predispose an individual to it. 30–50% of individuals with focal hyperhidrosis have a family history of the condition. A child born to a parent with hyperhidrosis has a 25% chance of inheriting the condition.
Focal hyperhidrosis affects both children and adults. Onset is typically during early adulthood; though palmar and axillary hyperhidrosis generally first occur in adolescence. Studies of the ways in which symptoms and consequences of hyperhidrosis change over time have not been conducted. However, based on clinical experience, doctors believe that excessive sweating usually declines past age 50.
The majority (two thirds) of people with focal hyperhidrosis do not discuss their condition with a doctor, either because they are embarrassed, or because they are unaware it is a treatable medical condition. This makes it challenging for doctors to diagnose hyperhidrosis, and often the condition is only recognised when an individual goes to the doctor for another condition and mentions excessive sweating during the consultation.
If a doctor suspects you have focal hyperhidrosis, they may enquire about your sweating symptoms to determine whether or not you have hyperhidrosis and if it is generalised or focal. Questions may include:
- How long ago did excessive sweating begin?
- How old were you when excessive sweating began?
- Do any members of your family experience excessive sweating?
- Which areas of your body are affected by excessive sweating? Does it affect your whole body or distinct sites such as the hands and armpits?
- Do you experience sweating at night while sleeping?
- Do you have any other medical conditions? In particular, do you have a medical condition affecting your endocrine or nervous systems, or an infection? Having another medical condition makes generalised hyperhidrosis more likely than focal. Some medical conditions also influence the best course of treatment for hyperhidrosis;
- How often do you sweat excessively?
- How badly do you sweat? Does the excessive sweating interfere with your daily activities?
- Do you experience any other symptoms at the same time as excessive sweating?
- Is there anything that triggers you excessive sweating?
Differentiating between focal and generalised hyperhidrosis is the first diagnostic step, because generalised hyperhidrosis is often the result of an underlying medical condition. It is important for the doctor to treat the underlying condition (if present) or conduct appropriate tests to rule out secondary causes of hyperhidrosis.
Focal hyperhidrosis occurs in otherwise healthy individuals and may be classified as:
- Primary idiopathic hyperhidrosis (occurs most commonly in otherwise healthy individuals);
- Gustatory sweating (Frey’s syndrome);
- Neurologic hyperhidrosis (occurring as a result of nerve or spinal cord injury).
It may affect one or more body sites and may be further classified according to the site or sites affected. The hands, feet, face and armpits are most commonly involved, though excessive perspiration may occur at any body site.
Primary idiopathic hyperhidrosis
Primary idiopathic hyperhidrosis is characterised by excessive sweating at one or more site for > 6 months. For the doctor to make a diagnosis of primary idiopathic hyperhidrosis, the sweating must meet at least two of the following criteria:
- Bilateral sweating (sweating on both sides) which is relatively symmetrical;
- At least one episode of excessive sweating per week;
- Impairment of daily activities due to excessive sweating;
- Onset before age 25;
- Family history of hyperhidrosis;
- Absence of nocturnal sweating.
Psychosocial aspects of hyperhidrosis
Hyperhidrosis can cause significant psychosocial impairments, including interference with daily activities and impaired social functioning due to embarrassment and humiliation associated with excessive sweating. Sweating-related symptoms such as touch avoidance and physiological symptoms of social anxiety disorder (e.g. blushing, trembling) may also occur in some individuals, particularly those with affected hands. Hyperhidrosis can have a considerable detrimental effect on quality of life. It is important to discuss the psychosocial aspects of hyperhidrosis with your doctor so that they can be considered when devising a treatment plan.
The doctor may enquire about:
- Experience of embarrassment due to sweaty palms or wet clothing;
- Avoidance of hand shaking;
- Requirement to change clothes two or more times per day;
- Frustration with daily activities;
- Impairment at work, including reduced productivity;
- Changes to leisure activities;
- Avoidance of social gatherings;
- Depression or lack of confidence;
- Skin maceration associated with chronic moisture;
- Difficulties in social or intimate relationships.
A simple scale such as the hyperhidrosis severity scale, on which you rate your sweating symptoms on a four-point scale, may be used to help the doctor determine the extent of hyperhidrosis.
Select the response which best describes your sweating: If you are using the tool to monitor the effect of treatment, validation studies of this severity scale show that a one-point reduction in severity is associated with a 50% reduction in sweating. A two-point reduction is associated with an 80% reduction in sweating. References
How would you rate the severity of your excessive sweating?
1. Eisenach JH, Atkinson JLD, Fealey RD. Hyperhidrosis: Evolving Therapies for a Well-Established Phenomenon. Mayo Clinical Proc. 2005; 80(5):657-66. [Abstract | Full Text]
2. International Hyperhydrosis Society. Hyperhidrosis disease severity scale. 2007. [cited 1 February 2012]. Available from: [URL Link]
Select the response which best describes your sweating:
If you are using the tool to monitor the effect of treatment, validation studies of this severity scale show that a one-point reduction in severity is associated with a 50% reduction in sweating. A two-point reduction is associated with an 80% reduction in sweating.
The key physical symptom of hyperhidrosis is visible signs of excessive sweating (e.g. damp clothing). In addition, physical complications arising due to wetness (e.g. maceration of the soles), suggest hyperhidrosis. The doctor will need to conduct an examination to determine the pattern of excessive sweating and to look for secondary causes of hyperhidrosis.
How is it Diagnosed
While history and examination are typically sufficient to diagnose hyperhidrosis, other investigations may be used to help determine the extent and severity of the condition.
Iodine starch test
An iodine starch test may be used to identify the areas affected by hyperhidrosis. This test involves applying an iodine solution to the sites thought to be affected by hyperhidrosis. The skin should be cleaned, dried and shaved before the solution is applied. The surfaces are then sprinkled with starch. In the presence of sweat, iodine and starch will react, leaving a purple residue. The areas of skin that stain purple when the starch is applied are the sites of the sweat gland ducts responsible for excessive sweating. For example, in axillary hyperhidrosis a particular area of the underarm, rather than the entire armpit, may stain purple.
Photographs may be taken to document the areas of excessive sweating and can be used as a measure against which future photographs can be compared to assess the effectiveness of treatment. Alternatively, areas that stain purple may be circled with a water-proof marker to enable targeted treatment (e.g. botulinum toxin A injections). You will need to stop using antiperspirant deodorant and other treatments you use to stop sweating for 5 days before the test. You should not take the test after using an anaesthetic.
Gravimetric analysis of sweat from the region implicated in hyperhidrosis may be conducted following iodine starch testing. A piece of filter paper that has been weighed on high-precision scales is placed over the region for 60 seconds. The paper absorbs the sweat. When the paper is removed, it is weighed again so that the amount of sweat absorbed can be determined and the rate of sweating (in milligrams per centimetre squared per minute) calculated.
Thermoregulatory sweat test
The thermoregulatory sweat test involves applying a powder containing alizarin red, corn starch and sodium carbonate to the skin on the front of the body, the hands and the feet. Areas of skin affected by hyperhidrosis immediately stain a light orange colour, allowing the doctor to identify the sites affected in the resting state. Photographs are taken to document the skin stain at this stage.
After the photographs are taken, the individual is placed in a heated tent until their oral temperature rises to 38oC. Increasing the body and oral temperature allows the doctor to assess the changes in sweating that occur in response to heat. Typically, profuse sweating will occur in areas affected by hyperhidrosis, while areas involved in normal thermoregulatory sweating only will produce less sweat. The dark purple stained areas indicate areas of the body involved in hyperhidrosis sweating, while areas stained orange in the presence of heat are involved only in normal thermoregulatory sweating.
Photographs are taken again to enable the production of computer generated images, from which the percentage of the entire body surface involved in thermoregulatory sweating and the percentage affected by hyperhidrosis can be calculated, based on the body surface areas that stain light orange and/or purple at different stages of the test.
Numerous treatments are available for the focal hyperhidrosis and effectiveness is high (90–95%). However, many treatment options are invasive and/or require repeat treatment or maintenance therapy. Early diagnosis and treatment can have considerable positive implications for the affected individual’s quality of life, but individuals with hyperhidrosis typically do not seek medical treatment for their condition and many fail to recognise their excessive perspiration is a treatable condition.
Hyperhidrosis causes decreases in water and electrolytes which may lead to dehydration if fluids are not replaced.
While hyperhidrosis is not a life- or health-threatening condition, it carries a substantial psychosocial burden and may interfere with the day-to-day life of affected individuals. Excessive sweating may inhibit an individual’s social or occupational functioning.
Palmar hyperhidrosis occurs in response to emotional and environmental stimuli and can have a significant impact on daily functioning. Properly hydrated skin on the palms helps with grip and hyperhidrosis interferes with all tasks requiring manual dexterity. It may have psychological consequences as the condition is difficult to conceal. Individuals with palmar hyperhidrosis may avoid touching other people because their palms are typically cold, wet and slippery. The condition can lead to embarrassment and/or isolation in professional, social and intimate relationships.It may also impair work tasks, for example if sweat drips onto a keyboard or document.
Plantar hyperhidrosis is a response to emotional and environmental stimuli. Compared to palmar hyperhidrosis, it is relatively easy to conceal. However, excessive sweating of the soles may lead to bromhidrosis (foul odour) or infection or maceration of the soles. It may also stain or damage footwear.
Craniofacial hyperhidrosis is most usually gustatory (stimulated by certain foods). In rare cases, the condition is primary and occurs in response to emotional and environmental stimuli, similar to the palmar–plantar condition.
Axillary hyperhidrosis usually involves both emotional and thermoregulatory pathways. Individuals with the condition usually have to change their clothes several times per day and do not find symptom relief with over-the-counter antiperspirants. These individuals may find clothing stained or damaged as a result of excessive sweating and experience embarrassment due to wet clothing.
Psychosocial complications also affect children with hyperhidrosis and may lead to further complications. For example, a report noted that a 14-year-old female had developed poor posture as a result of trying to hide sweat stains on her clothes.
Topical (applied to the surface), systemic (targeting the entire body) and surgical treatments all have a therapeutic role in focal hyperhidrosis. The most appropriate option depends on the severity of the condition. Moderate cases can usually be managed with topical agents (e.g. strong antiperspirants), while severe cases typically require invasive procedures such as either botulinum toxin A injections or surgery.
Treatment typically starts with the simplest method known to relieve the specific type of hyperhidrosis (e.g. facial). If that treatment is unsuccessful, the doctor will continue to prescribe alternative treatments, as detailed in the table below. In addition to these treatments, lifestyle changes may be recommended to reduce the impact of sweating.
Table 1: Treatments for hyperhidrosis
|First line||Topical agents (most commonly aluminium chloride)||Topical agents (most commonly aluminium chloride)||Topical agents (most commonly aluminium chloride)||Oral medications|
|Second line||Botulinum toxin A injections||IontophoresisorOral medications||IontophoresisorOral medications||Topical agents (most commonly aluminium chloride)|
|Third line||Oral medications||Botulinum toxin A injections|
|Fourth line||Local surgeryorEndoscopic thoracic symphathectomy||Botulinum toxin A injections||Botulinum toxin A injections||Endoscopic thoracic sympathectomy|
|Fifth line||Endoscopic thoracic symphathectomy||–||–|
Lifestyle components of management
While lifestyle changes cannot reduce sweating, they may reduce complications associated with excessive sweating (e.g. infection). It is important to bathe daily and thoroughly dry skin so that it is less hospitable for bacteria. Thoroughly drying the feet is particularly important in cases of plantar hyperhidrosis.
Individuals with affected feet should wear wool or cotton (not synthetic) socks, rotate their shoes and air their feet regularly. Wearing clothes made from cotton, wool, silk or other breathable materials may help people with axillary hyperhidrosis, as may using perfume-free deodorants.
As focal hyperhidrosis may occur in response to emotional stimuli, practicing relaxation techniques may also be helpful.
Antiperspirants with high concentration aluminium salts
Topical antiperspirants used to treat focal hyperhidrosis are similar to antiperspirant deodorants purchased over the counter, but typically contain higher concentrations of aluminium salts (20–25% compared to 12% for over-the-counter varieties). The way in which aluminium salts work to prevent sweating is not well understood. It appears that the salts obstruct eccrine sweat gland ducts and/or destroy the cells in the sweat glands responsible for sweat secretion.
25% aluminium salt antiperspirants are recommended for first-line treatment of mild axillary hyperhidrosis; 20% aluminium chloride in alcohol may also be used and is effective in treating 98% of mild axillary cases. Repeat application every 24–48 hours is typically required. In mild cases, improvements are seen within 3 weeks of starting treatment.
Topical antiperspirants with 20% aluminium salts may also be used to treat palmar hyperhidrosis, and may reduce sweating within 48 hours of the first application. However, repeat application is necessary as sweating resumes within 48 hours of the last application.
In more severe cases, sweat may react with the aluminium chloride solution and cause skin irritation. In these cases, a different type of alcohol containing 20% aluminium salts is usually prescribed. The solution should be applied to dry skin and washed off 6–8 hours after application. It is most effective if the affected area is covered (e.g. with clothing, gloves or shower cap). In the initial phase of treatment, nightly application is required. When the desired response is achieved the application can be reduced to 1–2 times per week.
Repeat application is required for permanent reduction in sweating, but application of the solution can be cumbersome. Strict adherence to all steps of the application process is required or the best result will not be achieved. The treatment may be ineffective in severe cases. Regardless, it remains the treatment of choice for individuals with excessive axillary sweating.
Local irritation (e.g. burning and stinging) is the most common side effect and may be reduced by applying the products at bedtime and cleaning the armpits to remove the solution 6–8 hours after application. Irritation with these agents is much less than with aldehyde agents (e.g. formaldehyde), which are rarely used in hyperhidrosis treatment due to local irritation and skin reactions.3
Topical preparations containing aluminium salts are considered safe for use in, and are also recommended as the first-line treatment for, children with focal hyperhidrosis. This is partly because they are non-invasive in nature and safer than other forms of treatment.
The most effective treatment for craniofacial hyperhidrosis is topical application of 0.5% glycopyrrolate solution, cream or roll-on.
Iontophoresis is the introduction of ions (electric charges) to affected areas of skin, via application of an electric current. The way in which this treatment works to reduce sweating is not well understood. The therapy is thought to reduce sweating either by obstructing the sweat gland duct or by disrupting sweat secretion. Sweat secretion involves a complex chain of events in which potassium, sodium and chloride ions are exchanged to convert the primary solution produced by the sweat glands into sweat.
Iontophoresis may be performed by a health practitioner, in which case it involves placing the affected area of skin in a shallow basin of water through which an electrical current is passed. Commercial devices which can be used by individuals to perform iontophoresis at home have been available since the mid-1980s, though the one-off cost of the device (~$600–1,000) may prevent some individuals from using this form of treatment. Iontophoresis devices deliver a current through wool pads saturated with tap water, which are separated from the treatment site by a non-conducting barrier. The user controls the amperage (the strength of the electric current), which should be set at the highest tolerable level. Daily, and sometimes twice daily, treatment for 30 minutes per affected site is required to temporarily reduce sweating (usually for several weeks). Repeat treatment is then performed as needed.
Iontophoresis is usually used to treat palmo-plantar hyperhidrosis as the arms and feet can be easily submerged. In these cases it is usually instituted as second-line treatment when topical antiperspirants are ineffective. The treatment is effective in 80–100% of palmo-plantar hyperhidrosis cases. However, it is time consuming, involving 30–40 minute treatment of each affected site at least 4 days a week. 6–10 treatment sessions are usually required to achieve normal sweating and maintenance therapy is typically needed.
The treatment is further limited by skin irritation and cannot be used by pregnant women or people with a pacemaker or orthopaedic prosthesis. Clinical trials of the device have included children > 12 years of age.
Botulinum toxin A injections
Intradermal injection of botulinum toxin A is a well studied and highly effective treatment for hyperhidrosis. It is most commonly used when the armpits are affected. Before botulinum toxin A is administered, a starch iodine test should be performed to identify the hyperhidrotic area. When injected under the skin of affected sites, botulinum toxin A inhibits the release of acetylcholine, a chemical involved in the transmission of nerve signals to the eccrine sweat glands. This reduces sweat secretion.
Despite the treatment involving significant pain (anaesthetic is often required prior to administration), almost all individuals who use this treatment are satisfied with the outcomes. Maintenance therapy every 4–17 months is typically required. There is no evidence of the effectiveness diminishing with second and third treatment. However, some scientists believe that over time antibodies to botulinum toxin A may form and inhibit its antiperspirant effects. This may limit the long-term use of botulinum toxin A therapy.
There is limited experience using botulinum toxin A injections to treat children with focal hyperhidrosis, though reports from individual cases of children who have used this treatment indicate it is highly effective.
Individuals who cannot safely use botulinum toxin A injections include those with neuromuscular disorders, who are pregnant or breastfeeding, and/or are using medications that interact with botulinum toxin A. Use of this treatment is limited because of the high cost and need for a specialist to perform the injections. Botulinum toxin A is available fully subsidised under special access to certain specialists under the Australian Pharmaceutical Benefits Scheme (PBS) for severe primary hyperhidrosis of the axillae (armpits).
In cases of axillary hyperhidrosis, the botulinum toxin A dose is administered as numerous tiny injections covering the entire hyperhidrotic area of each armpit. Injections are spaced ~1.5 cm apart. Injections to the armpit are less painful than injections at other sites, but occasionally, a local anaesthetic in the form of cream may be required. This therapy effectively treats 95% of axillary hyperhidrosis cases within a week of administration. The effects last, on average, for 7 months, but can be shorter or longer.
In cases of palmar hyperhidrosis, injections to the palms are spaced ~1 cm apart and placed to cover the entire hyperhidrotic area. Injecting the palm involves significant pain and a strong anaesthetic may be required.
In the treatment of palmar hyperhidrosis, botulinum toxin A is 90% effective for a duration of 4–6 months. However, the treatment is associated with hand muscle weakness and impaired fine motor skills, which may make it inappropriate for those who require manual dexterity. In these cases, a trial using a lower dose, administered only to the non-dominant hand (e.g. the left hand of a right-handed individual) may be conducted. Avoiding deep injection into the palmar muscles also reduces the risk of this side effect. In addition, the risk of hand dysfunction due to paralysis of hand muscles is high, which means other treatments are usually instituted for palmar hyperhidrosis.
Botulinum toxin A injections may be useful in some cases of craniofacial hyperhidrosis, but should only be tried if all other treatments fail to relieve the condition.
Plantar hyperhidrosis may also be treated with botulinum toxin A injections. However, due to the large surface area of the soles and because of the relatively sensitive nature of the skin of the feet, the treatment can be uncomfortable and cumbersome. To treat the feet, injections are spaced ~1 cm apart and should cover the entire hyperhidrotic area. A strong anaesthetic may be needed for pain relief. Excellent response rates for plantar hyperhidrosis have been reported.
Surgical treatments may be used for hyperhidrosis in patients who fail to respond to other therapies, and who are well informed of the potential risks and benefits of the treatments. While the initial cost of performing surgery is greater than the cost of other treatments, the costs may be attenuated over time as there is no need for maintenance therapy, as with non-surgical treatments.
Removal of axillary tissue
Surgery to remove tissues from the armpit, either by excision (cutting) or curettage (scraping) followed by liposuction, may be used in cases of axillary hyperhidrosis. The treatment is usually the first type of surgery trialled, as other surgical procedures involve greater risks.
Removal of axillary tissue is performed under local anaesthesia and involves removal of eccrine and apocrine glands lying just under the skin. An incision is made to the skin of the affected area (identified by, for example, a starch iodine test) to enable removal. Results should be permanent and 91% of people treated experience significant improvements in sweating. However, there are numerous adverse events associated with the procedure, including scarring, hair loss, hyperpigmentation, pain and bruising.
Endoscopic thoracic sympathectomy
Endoscopic thoracic sympathectomy is a surgical procedure through which the sympathetic nerve fibres between thoracic (mid-spine) vertebrae 2 and 3 (and sometimes 4) are excised or otherwise destroyed, using a minimally invasive technique guided by an endoscope (a medical device used for viewing the inside of body cavities).
Similar to more invasive surgical sympathectomy techniques, endoscopic thoracic sympathectomy provides long-term relief of hyperhidrosis. It is 68–100% effective in cases of axillary, palmar and facial hyperhidrosis, and 58–85% effective in cases of plantar hyperhidrosis, although in plantar cases improvements are more modest. It is also a treatment option for cases of severe craniofacial hyperhidrosis.
The procedure involves a single, small incision which provides access to nerve fibres on both sides of the body. Different surgical techniques are used depending on which site is affected by excessive sweating. For example, in cases of isolated axillary hyperhidrosis, the surgery involves destroying the nerves in the thoracic vertebrae 2–4, whereas in craniofacial cases other nerves are removed.
Most patients are satisfied with the results of the surgery, though in some cases partial sweating may persist despite satisfaction.
Compensatory mild to severe hyperhidrosis involving the trunk and lower limbs occurs in the majority of individuals (86%) following the surgery, and this causes satisfaction to decline. Children < 14 years of age reportedly tolerate compensatory sweating better than their older counterparts and therefore are more satisfied with this surgery.
There are a number of serious adverse events associated with the surgery:
- Great vessel injury (injury of the thoracic artery and associated blood vessels), a life-threatening condition which is extremely rare in this context;
- Haemopneumothorax (air and blood in the chest cavity) requiring chest tube;
- Neuralgia (nerve pain) which may be prolonged, transient or intercostal.
Other cosmetic complications such as Horner’s syndrome (damage to the facial muscles which may cause drooping eyelids and other abnormalities) affects 12% of patients treated with endoscopic thoracic sympathectomy.
Lumbar sympathectomy, or removal of the nerves connecting the second vertebra of the lumbar (lower) spine, may be used to treat plantar hyperhidrosis. These nerves are also responsible for innervation of the genitals in men and women. Ejaculatory and erectile dysfunction are almost universal in men following this treatment and some doctors reserve its use for female patients. However, this tactic is questionable as the nerves of the second lumbar vertebra also provide genito-sexual innervation for women and lumbar sympathectomy is also expected to cause orgasmic failure in women.
Sympathotomy (also known as sympathicotomy) is a recent modification of endoscopic thoracic sympathectomy used in the treatment of palmar hyperhidrosis. Whereas endoscopic thoracic sympathectomy involves removal of the nerves connecting to the second and third thoracic vertebrae, sympathotomy involves disconnection of the nerves, which interrupts the transmission of nerve signals that cause sweating.
The surgery produces excellent results and reduces the rate of compensatory hyperhidrosis, the most common side effect of endoscopic thoracic sympathectomy. Side effects associated with the surgery include abnormal sudomotor control (regulation of the sweat glands) and mild changes in cardiovascular regulation.
Thorascopic division of the sympathetic trunk
Thorascopic division of the nerves between thoracic spine vertebrae 1 and 2 interrupts nerve transmission to the arm. One study reported a 100% response rate to this surgery with no cases of Horner’s syndrome (a common complication of other techniques). However, regrowth of nerve fibres limited the duration of effect to 9–12 months.
Systemic treatments do not have a well established role in treatment of focal hyperhidrosis, though emerging evidence suggests that they are convenient, cost effective and safe. Anticholinergic agents are the primary systemic treatment and work by inhibiting acetylcholine, a chemical involved in transmitting nerve signals to the sweat glands. High doses are required and the dose usually needs to be increased over the course of treatment to reduce sweating. This limits the use of this therapy because high doses are also associated with numerous adverse effects. These include sedation, dry mouth and constipation. Individuals usually stop using anticholinergic agents due to dry mouth. However, due to their low cost and convenience, oral anticholinergics may be trialled as second- or third-line therapy for palmar and plantar hyperhidrosis.
Systemic clonidine (a medicine also used to regulate blood pressure) was reported to achieve complete remission of craniofacial hyperhidrosis after 3 weeks treatment. In this case, 20% aluminium chloride solution was also applied nightly and the majority of the clonidine dose was taken at night to avoid daytime sedation. In the study, mild daytime sedation was reported as an added benefit of the treatment.
There is no evidence that alternative therapies such as hypnosis, biofeedback training or relaxation techniques are effective treatment for hyperhidrosis. However, no trials have been conducted to assess the efficacy of alternative treatments.
Article kindly reviewed by:
Associate Professor Karl Ng MB BS (Hons I) FRCP FRACP PhD CCT Clinical Neurophysiology (UK) Consultant Neurologist – Sydney North Neurology and Neurophysiology (download referral form and map); Conjoint Associate Professor – Sydney Medical School, University of Sydney; and Editorial Advisory Board Member of the Virtual Neuro Centre.
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