Excessive Sweating (Hyperhidrosis)

Hyperhidrosis is a medical term used to describe the condition of excessive and uncontrollable sweating.

Sweat is a weak salt solution naturally produced by the eccrine sweat glands. Eccrine sweat glands are found all over the body, especially on the palms and soles.

Hyperhidrosis can be localised, affecting the armpits, soles, palms, or face, or generalised, affecting most or all of the body. It can be primary or secondary.

Primary Hyperhidrosis

Primary hyperhidrosis results from overactivation of the hypothalamic thermoregulatory centre in the brain. It is transmitted through the sympathetic nervous system into the eccrine sweat glands. The condition starts during childhood or adolescence. It can be persistent throughout the entire lifespan or improve with age. Primary hyperhidrosis can also be inherited and passed from one generation to another. Armpits, soles, or palms are affected symmetrically. Triggering agents of sweating attacks include exercising, anxiety, hot weather, fever, and spicy food. Sweating attacks typically decrease at night and completely disappear during sleep.

Secondary Hyperhidrosis

Secondary hyperhidrosis is less common than primary hyperhidrosis and can occur at any age. It is not symmetrical and may occur at night or during sleep. The condition is generally caused by neurological or endocrine conditions.

Secondary localised hyperhidrosis may be triggered by the following causes:

• Spinal nerve damage
• Stroke
• Peripheral nerve damage
• Brain tumour
• Neuropathy
• Chronic anxiety disorder

Secondary generalised hyperhidrosis can be caused by the following conditions:

• Obesity
• Menopause
• Diabetes
• Respiratory failure
• Overactive thyroid
• Cardiovascular disorders
• Parkinson disease
• Hodgkin lymphoma

Certain drugs, such as caffeine, alcohol, tricyclic antidepressants, opioids, and nicotinamide can also cause secondary generalised hyperhidrosis.

Impact on Daily Life

Hyperhidrosis tends to interfere with many daily activities and negatively affects quality of life. During axillary hyperhidrosis, clothing becomes damp and stained, requiring multiple changes throughout the day. Wet skin folds may develop further medical conditions such as infection, irritant dermatitis, and chafing. Palmar hyperhidrosis causes slippery hands, leaves marks on paper and fabrics, and creates difficulties using electronics such as trackpads and keypads. Individuals may avoid handshaking due to embarrassment and may find it difficult to write neatly. Plantar hyperhidrosis affects the soles of the feet, causes unpleasant odour, damages footwear, and can lead to a blistering type of dermatitis as well as secondary infection.

Diagnosis

Hyperhidrosis is diagnosed clinically and requires a dermatologic consultation. Localised hyperhidrosis is assessed through the Minor test. Iodine is applied to the patient's skin and allowed to air dry, after which starch is dusted over the iodine. Sweating is indicated if the colour changes to a dark blue-black colour. Secondary generalised hyperhidrosis requires consideration of additional clinical features during diagnosis; for example, blood sugar and thyroid function tests may be requested.

Treatment Options

Numerous treatment methods are available for hyperhidrosis. Many topical antiperspirants are available on the market, and a range of oral medications may be prescribed as a course of treatment. Botulinum toxin injections are medically approved for the treatment of hyperhidrosis and have demonstrated effective results in reducing excessive sweating.