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What is Hyperhidrosis?

Hyperhidrosis is the name given for excessive and uncontrollable sweating. Sweat is produced by the eccrine sweat glands. They are distributed over the entire body but are most numerous on the palms and soles (with about 700 glands per square centimeter).

Who gets hyperhidrosis?

Primary hyperhidrosis is reported to affect 1–3% of the U.S. population and nearly always starts during childhood or adolescence. The tendency may be inherited.

What causes hyperhidrosis?

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

Triggers to attacks of sweating may include: hot weather, exercise, fever, anxiety, spicy food

What are the clinical features of hyperhidrosis?

Hyperhidrosis can be localized or generalized. Localized hyperhidrosis affects armpits, palms, soles, face, or other sites and generalized hyperhidrosis affects most or all the body. Primary hyperhidrosis, which starts in childhood or adolescence, can be genetic and it tends to involve armpits, palms, and/or soles symmetrically and usually, the sweating reduces at night and disappears during sleep.

Secondary hyperhidrosis is less common than primary hyperhidrosis and more likely to be unilateral and asymmetrical, or generalized. It can also occur at night or during sleep and can be related to endocrine or neurological conditions or medications.

What is the impact of excessive sweating?

Hyperhidrosis is embarrassing and interferes with many daily activities and quality of life.

Axillary hyperhidrosis

• Clothing becomes damp, stained, and must be changed several times a day

• Wet skin folds are prone to chafing, irritant dermatitis, and infection

Palmar hyperhidrosis

• Slippery hands lead to avoidance of handshaking

• Marks left on paper and fabrics

• Difficulty in writing neatly

• Malfunction of electronic equipment such as keypads and trackpads

• Prone to a blistering type of hand dermatitis (pompholyx)

Plantar hyperhidrosis

• Affects soles of the feet

• Unpleasant smell

• Ruined footwear

• Prone to a blistering type of dermatitis (pompholyx)

• Prone to secondary infection (tinea pedis, pitted keratolysis)

How is hyperhidrosis diagnosed?

Hyperhidrosis is usually diagnosed clinically. Tests relating to the potential underlying cause of hyperhidrosis are rarely necessary for primary hyperhidrosis.

The precise site of localized hyperhidrosis can be revealed using the Minor test. The Minor test is where an iodine solution is placed on the area of concern and air dried. Cornstarch is then dusted on iodine after sweating, which is revealed by a change in dark blue/black color.

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

• Blood sugar/glycosylated hemoglobin

• Thyroid function

Citation: Oakley, A. (2015, July 1). Hyperhidrosis. DermNet. Retrieved July 26, 2023, from

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