Introduction
Excessive sweating is surprisingly common. Many people will become fed up with the embarrassment of soaked armpits, the ruining of shirt after shirt and the frustration of sweaty palms when trying to hold cutlery or shake hands for business meetings.
Many people will suffer through this for years before seeking solutions. There is no clear answer for why some people sweat more than others. There are multiple creams, lotions and over the counter options to try to deal with excess sweat but few of them work particularly well.
Botulinum toxin, use for anti wrinkle treatments, is the most effective treatment and is increasingly used to offer relief to those who have to put up with excessive sweating.
What is excessive sweating?
Hyperhidrosis is the medical term for excessive sweating. This condition usually starts before the age of 25, occurs at least once per week, involves symmetrical areas of the body and disrupts daily life. It typically occurs in the armpits, hands, soles of the feet and may include any other part of the body. If you have visible,
excessive sweating without a cause, you may have this condition.
How Does Sweating Work?
The body has sweat glands all over the skin. Sweat assists with the regulation of body temperature by virtue of the evaporation of sweat which uses up heat energy. It also assists in fluid and salt balance. The palms and soles of the feet have the highest concentration of sweat glands and can start to sweat due to emotional stress. Otherwise, the rest of the skin will respond to heat stimuli to begin sweating. Thermal and emotional sweating are regulated by different areas of the brain; however the end pathway commonly involves the sympathetic nervous system and the acetylcholine neurotransmitter.
What kinds of Hyperhidrosis are there?
Primary Hyperhidrosis is excessive sweating not due to an identified cause. It is a diagnosis of exclusion, meaning that other causes of sweating need to be considered before approaching treatment.
Secondary hyperhidrosis is sweating caused by another factor. Your doctor will ask questions to determine the pattern of your sweating:
Night sweats that soak the sheets should be investigated for infections or systemic diseases.
Sweating that occurs in menopausal women and resolves after a distinct hot flush will be treated differently.
Sweating that occurs with a sense of excessive heat or other symptoms such as weight loss, dry skin, hair loss should prompt a review of hormone function.
Medications may be a cause of sweating.
Heavy metals or other forms of poisoning can also cause sweating.
Symmetrical sweating mostly affecting the scalp, face, palms, armpits and soles of feet in the absence of above causes is primary hyperhidrosis.
What tests are needed to diagnose hyperhidrosis?
Not all patients will require testing. If there are concerns about the pattern of sweating, tests to look for infectious response, inflammation, hormone activity etc. are recommended
What are the treatments for hyperhidrosis?
The simplest treatments for excessive sweating start with antiperspirant products. These typically need to have a metal component (aluminium) as the aluminium accumulates and blocks the sweat gland.
Over the counter or non-prescription aluminium based antiperspirants may only help the mildest cases of hyperhidrosis. Stronger concentrations are available on prescription however are known to cause irritation to some people which limits their use.
Appropriate clothing, ventilation may help some cases however most cases of hyperhidrosis will persist beyond these measures.
Anticholinergic based medications can be taken orally to help with sweating. Whilst effective, the side effect profile of these medications usually prohibits their use.
By far the most successful treatment is the use of botulinum toxin (e.g botox). Whilst this is commonly used for aesthetic procedures to treat wrinkles, botulinum toxin is also a powerful inhibitor of the chemical mediator, acetylcholine, that is required for the sweat glands to function. Studies have shown near 100% success with local injections of the toxin to hands, soles, armpits and parts of the scalp and face.
Whilst effective, botulinum treatment has some drawbacks. Typically large amounts of the toxin needs to be used. Multiple injections of 2-3 units at 1-1.5cm intervals over the affected areas can result in 50 units per area being used. Thus, it comes with expense and some pain. Mostly, pain can be minimised using anaesthetic creams and ice.
Treatment is very effective and begins to be so 7-10 days after injection; however repeat treatments will be required at the 9-12 month mark as botulinum toxin is not permanent.
Finally, care must be taken not to inject botox into key muscles especially if treating the face.
In addition to botulinum toxin, surgical procedures have been used. This includes a procedure to surgical remove the sweat glands as well as a procedure to cut the sympathetic nerves supplying the sweat glands. There are electrical based therapies also in use however the volume of literature favours the use of aluminium based antiperspirants and/or botulinum toxin.
Smith, C., (2019) Primary focal hyperhidrosis. UpToDate. OFori, A. O., Retrieved 12 July 2019
https://www.uptodate.com/contents/primary-focal-hyperhidrosis
