Hyperhidrosis (excessive sweating)

Dr Haran Sivapalan

What is hyperhidrosis?

Hyperhidrosis is a condition whereby a person sweats too much. It may either have no identifiable cause (primary hyperhidrosis) or result from an identifiable underlying cause (secondary hyperhidrosis) such as pregnancy, menopause or an overactive thyroid gland.  Sweating can affect the whole body (generalised) or be restricted to specific parts of the body (focal) such as the armpits, hands, face or scalp.

Between 1 and 3% of people are thought to have hyperhidrosis. Excessive sweating can be a source of psychological distress and may interfere with a person’s daily life. Treatment for hyperhidrosis varies depending on the severity and causes and range from aluminium chloride based anti-antiperspirants and topical creams to surgical solutions.

There are a variety of lifestyle tips and modifications that can also help with the condition including avoiding known triggers such as caffeine or hot or spicy foods, wearing loose fitting clothes and leather shoes, and getting help with anxiety if that is a contributing factor.

Hyperhidrosis doesn’t generally cause body odour as a result of sweating, as unpleasant smelling sweat is secreted by “apocrine” and not “eccrine” sweat glands. Bacteria on the skin and in clothes, however, can cause unpleasant body odour by degrading the sweat.

Hyperhidrosis can be classified into two main types depending on its cause:

  • Primary hyperhidrosis – no identifiable cause of sweating
  • Secondary hyperhidrosis – sweating is the result of another identifiable cause such as pregnancy, medication use, thyroid conditions etc.

Some studies suggest that primary hyperhidrosis might be due to inappropriate activation of sweat glands (particularly “eccrine sweat glands”) by the sympathetic nervous system – the part of the nervous system responsible for the body’s fight or flight reaction.

Primary hyperhidrosis may also run in families, suggesting that there is an underlying genetic component to the condition.

Secondary hyperhidrosis is excessive sweating that has another identifiable cause. Possible causes include:

  • Pregnancy
  • Menopause
  • Anxiety
  • Certain medications – including antidepressants, pilocarpine eye drops, anticholinesterase drugs (e.g. pyridostigmine
  • Substance abuse and withdrawal (including alcohol, as well as other recreational drugs)
  • Obesity
  • Low blood sugar (hypoglycaemia)
  • Certain cancers – including lymphoma (cancer of the white blood cells), phaeochromocytoma (a tumour of the adrenal gland)
  • Infections – e.g. tuberculosis, HIV, malaria
  • Parkinson’s disease
  • Endocrine conditions – e.g. hyperthyroidism, pituitary conditions

The main symptom of hyperhidrosis is excessive sweating.

There is no fixed rule as to what amount of sweating counts as “excessive.”  People may seek help when they find sweating poses problems with everyday activities. For example, people may have difficulty in gripping objects, find they have to regularly change clothes, or may avoid social activities due to fear of embarrassment. For many people with the condition, hyperhidrosis can be a cause of psychological distress.

Hyperhidrosis may affect the whole body (generalised hyperhidrosis) or affect specific body parts (focal hyperhidrosis).

Primary focal hyperhidrosis has no identifiable cause and tends to affect the armpits (axillae), palms, soles of feet and scalp. It commonly starts in childhood or adolescence. Secondary focal hyperhidrosis also affects the same specific body areas, but there is an identifiable underlying cause such as anxiety or thyroid condition.

Generalised hyperhidrosis causes sweating all over the whole body and tends to have an identifiable underlying cause (secondary hyperhidrosis).

Hyperhidrosis doesn’t generally cause body odour due to sweating, as unpleasant smelling sweat is secreted by “apocrine” and not “eccrine” sweat glands. Bacteria on the skin and in clothes, however, can cause unpleasant body odour by degrading the sweat.

Hyperhidrosis may increase the risk of developing certain skin infections.

Excessive sweating increases the likelihood of developing a fungal infection, such as ringworm, athlete’s foot and fungal nail infections. This is because the sweat produces moist conditions in which fungal spores can thrive.

Sweating also increases the chances of developing warts – small, rough bumps on the skin caused the HPV virus.

Boils are swollen, pus-filled lumps on the skin that are sometimes associated with sweating. This is because sweating can facilitate infections of hair follicles.

A GP will ask you further questions about the symptoms you are experiencing: including how often you sweat, where on the body you sweat, whether you sweat at night, whether you have any other symptoms such as weight loss, fever or palpitations. Your GP will also want to know what other medications you are taking.

In the event the GP thinks your sweating is the result of another underlying cause (secondary hyperhidrosis), they may want to order further tests.

Referral to a specialist

You may be referred to a specialist to help diagnose and help treat the underlying cause of secondary hyperhidrosis. A dermatologist can also offer a wider range of treatments for primary and secondary hyperhidrosis.

Treatment varies according to whether you have primary or secondary hyperhidrosis. Treatment for secondary hyperhidrosis depends on the exact underlying cause. For example, sweating secondary to bacterial infection may be treated with antibiotics, whereas sweating due to anxiety may respond to psychological therapy.

For primary hyperhidrosis, there are various treatment options.

1. 20% aluminium chloride hexahydrate: Aluminium chloride is available as a roll-on, spray and liquid antiperspirant as well as dusting powder. It is applied to the armpits, feet, hands or face and reduces sweating by plugging the sweat glands.

Initially, aluminium chloride is usually applied to the skin before going to bed at night, every 1-2 days. After sweating improves, you may still need to apply aluminium chloride, albeit less frequently.

Aluminium chloride antiperspirants are available from pharmacies and can also be obtained via prescription form your GP. The antiperspirants can cause irritation when applied to the skin. Your GP may advise you to use emollients, soap substitutes or hydrocortisone cream in order to reduce skin irritation.


2. Modified topical therapy: A dermatologist may prescribe a mixture of topical treatments to be applied to the skin. These may include emollients (moisturising lotions and creams), topical corticosteroids, topical formaldehyde and glutaraldehyde solutions.

For sweating particularly affecting the face and scalp, a dermatologist may prescribe topical glycopyrrolate. This is a class drug known as an anti-muscarinic. It works by blocking the effect of the a chemical known as acetylcholine, which ordinarily stimulates sweat glands


3. Iontophoresis: Iontophoresis involves immersing affected areas of skin in water (or applying a wet pad) and then passing a weak electric current through the water. Iontophoresis is effective for focal hyperhidrosis affecting the palms, soles and armpits, although it is unclear how it works. Some theories suggest the electric current interferes with the nerves supplying the sweat glands. Others suggest that it helps thicken the outer layer skin, thereby blocking the sweat glands.

The treatment is usually performed in hospital, although home kits can be bought privately. These range from £250-£500. People generally require 2-4 treatment sessions a week, with each treatment session lasting between 20 and 30 minutes. Tap water is normally used, but (in hospital settings) the drug glycopyrronium is sometimes added to the solution for more severe cases of hyperhidrosis.

Iontophoresis has no serious side effects, but the electric current may briefly cause mild discomfort. People usually notice improvement after 4-10 sessions of iontophoresis.


4. Botulinum toxin (Botox): Botulinum toxin is a drug which blocks nerve signals from the brain to the sweat glands. It is administered as an injection and used to treat focal hyperhidrosis affecting the armpits, palms, soles or face.

Treatment with botulinium toxin requires several (usually around 15-20) injections to given to the affected skin in one sitting. The treatment effect normally last several months, after which further injections may be required.

Botulinum toxin is shown to be effective but can cause side effects including:

  • pain, redness and itching at the injection site
  • nausea, headaches and hot flushes
  • muscle weakness
  • other areas of your body sweating –a phenomenon known as ‘compensatory sweating.’

 Treatment with botulinum toxin is not always available on the NHS and is mostly administered in private clinics.


5. Antimuscarinic drugs

Antimuscarinic drugs include propantheline bromide, oxybutynin and glycopyrronium bromide. They work by blocking the effect of the chemical acetylcholine. Acetylcholine binds to receptors on sweat glands and stimulates them to produce sweat.

A dermatologist may prescribe antimuscarinic drugs for generalised hyperhidrosis. They have side effects such as dry mouth, blurred vision, stomach cramps and constipation.


6. Surgery

Surgical treatments are available for severe cases of hyperhidrosis that have not responded to medication or other treatments. There are two main options:

  • Resection or destruction of sweat glands
  • Endoscopic thoracic sympathectomy

Resection or destruction of sweat glands

For small areas of focal hyperhidrosis (particularly in the armpits), a procedure to cut out (resect) the sweat glands may be useful. Alternatively, a laser device can be inserted through an incision and used to shrink and destroy the sweat glands. In some centres, no incision is needed and a special probe is used to destroy the sweat glands using radiation. The procedures can be performed under local anaesthetic.

Endoscopic thoracic sympathectomy (ETS)

ETS involves cutting the sympathetic nerves that supply the sweat glands. The procedure is performed under general anaesthetic and two incisions are made on either side of the chest. A tube-like instrument with a camera and cutting tools is then inserted via the incisions and used to cut or clip the sympathetic nerves.

ETS is not always successful and carries certain risks, including:

  • Compensatory sweating – a common side-effect which causes increased sweating in other parts of the body.
  • Sweating of the face and neck after eating food – a phenomenon known as gustatory hyperhidrosis. This affects up to 50% of people undergoing ETS.
  • Air being trapped in the chest – a condition known as pneumothorax. This usually resolves spontaneously.
  • Horner syndrome – a rarer complication whereby the eyelid on one side droops.

Surgical treatments for hyperhidrosis are not always available on the NHS and may need to be undertaken privately.

Making changes to lifestyle can help people live more easily with hyperhidrosis. The following may be useful:

Avoid known triggers –some people’s sweating is triggered by certain factors such as spicy foods, caffeine or crowded rooms. Avoiding these triggers where possible will reduce the frequency of sweating.

Use antiperspirant rather than deodorant – antiperspirants are designed to reduce sweating and their frequent use may help in hyperhidrosis.

Avoid tight clothing made from synthetic fabrics – tight clothing made from materials such as nylon can increase sweating.

Consider wearing white or black clothing – this may minimise external signs of sweating.

Wear moisture-wicking socks – these may be particularly helpful in hyperhidrosis affecting the soles of the feet. They should be changed at least twice a day to reduce the risk of developing a fungal infection e.g. athlete’s foot.

Use absorbent soles and/or absorbent foot powder – these absorb sweat and moisture from the feet. Absorbent foot powder should be used twice daily.

Try to stick to leather shoes – these are less likely to accumulate sweat. It may also be helpful to alternate between different pairs of shoes to allow the sweat to fully dry out.

Consider wearing dress- or armpit- shields – these are pads that absorb sweat and protect clothes

Talk to your GP about help for anxiety – anxiety is a common cause of excessive sweating and there is lots of help available from counselling to medication.

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Hyperhidrosis. NHS Choices. (2015). Available at:  http://www.nhs.uk/Conditions/Hyperhidrosis/Pages/Introduction.aspx