DermNet NZ

Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


What is hyperhidrosis?

Hyperhidrosis is the name given to excessive and uncontrollable sweating.

Sweat is a weak salt solution produced by the eccrine sweat glands. These are distributed over the entire body but are most numerous on the palms and soles (with about 700 glands per square centimetre).

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Hyperhidrosis of palms and soles

Who gets hyperhidrosis?

Primary hyperhidrosis is reported to affect 1–3% of the US population and nearly always starts during childhood or adolescence. The tendency may be inherited, and it is reported to be particularly prevalent in Japanese people.

Secondary hyperhidrosis is less common and can present at any age.

What causes hyperhidrosis?

Primary hyperhidrosis appears to be due to overactivity of the hypothalamic thermoregulatory centre in the brain, and is transmitted via the sympathetic nervous system to the eccrine sweat gland.

Triggers to attacks of sweating may include:

Causes of secondary localised hyperhidrosis include:

Causes of secondary generalised hyperhidrosis include:

What are the clinical features of hyperhidrosis?

Hyperhidrosis can be localised or generalised.

It can be primary or secondary.

Primary hyperhidrosis

Secondary hyperhidrosis

What is the impact of excessive sweating?

Hyperhidrosis is embarrassing and interferes with many daily activities.

Axillary hyperhidrosis

Palmar hyperhidrosis

Plantar hyperhidrosis

How is hyperhidrosis diagnosed?

Hyperhidrosis is usually diagnosed clinically. Tests relate to potential underlying cause of hyperhidrosis and are rarely necessary in primary hyperhidrosis.

Screening tests in secondary generalised hyperhidrosis depend on other clinical features but should include as a minimum:

What is the treatment of hyperhidrosis?

General measures

Topical antiperspirants



Oral medications

Oral anticholinergic drugs:

Beta blockers:

Calcium channel blockers, nonsteroidal anti-inflammatory drugs and anxiolytics may also be useful for some patients.

Botulinum toxin injections

Surgical removal of axillary sweat glands

Overactive sweat glands in the armpits may be removed by several methods, usually under local anaesthetic.


Division of the spinal sympathetic nerves by chemical or surgical endoscopic thoracic sympathectomy (ETS) may reduce sweating of face (T2 ganglion) or armpit and hand (T3 or T4 ganglion), but is reserved for the most severely affected individuals due to potential risks and complications.

Lumbar sympathectomy is not recommended for hyperhidrosis affecting the feet as it can interfere with sexual function.

What is the outlook for hyperhidrosis?

Localised primary hyperhidrosis tends to improve with age. The outlook for secondary localised or generalised hyperhidrosis depends on the cause.

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Author: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand. Updated July 20145.

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If you have any concerns with your skin or its treatment, see a dermatologist for advice.