Understanding Hyperhidrosis
What Causes Excessive Sweating?
Sweating is essential for temperature control, but hyperhidrosis causes more sweating than the body needs for cooling. The cause depends on whether the sweating is primary—driven by overactive nerve signalling—or secondary to a medicine or another medical condition.
Normal sweating vs hyperhidrosis
Sweating helps regulate body temperature during heat, exercise and fever. Hyperhidrosis is different: sweating becomes excessive and can occur even when the body does not need additional cooling.
There are two main types—primary hyperhidrosis and secondary hyperhidrosis. Distinguishing between them matters because secondary sweating may require treatment of an underlying cause.
The two main causes of excessive sweating
Primary focal hyperhidrosis
Usually affects one or more focal areas such as both palms, soles or underarms. It often starts in childhood or adolescence and may run in families.
Secondary hyperhidrosis
Results from another medical condition, a medicine or another identifiable factor. It is more likely to be generalised and can occur during sleep.
What causes primary hyperhidrosis?
Primary hyperhidrosis is not simply a matter of having too many sweat glands. Current understanding points to excessive signalling through the sympathetic nervous system to eccrine sweat glands.
The nerves controlling sweating appear to over-react and signal sweat production even when cooling is not required.
Typical signs of primary focal hyperhidrosis
Starts relatively young
Symptoms commonly begin in childhood or adolescence rather than appearing suddenly later in life.
Usually symmetrical
Both palms, both soles or both underarms are commonly affected rather than only one side.
Family history may occur
The tendency can run in families, supporting a genetic contribution in some people.
Improves during sleep
Primary focal sweating typically reduces or stops during sleep. Night sweating raises more concern for a secondary cause.
Common triggers that can make sweating worse
Even when someone has primary hyperhidrosis, episodes can be intensified by normal sweating triggers such as heat, exercise, fever, anxiety and spicy foods.
These triggers do not necessarily cause the underlying disorder. Instead, they can amplify an already over-responsive sweating system.
Can stress or anxiety cause excessive sweating?
Emotional stress can trigger sweating, particularly on the palms, soles, underarms and face. People with primary hyperhidrosis may notice marked worsening during presentations, meetings or social situations.
However, hyperhidrosis should not automatically be dismissed as anxiety. Excessive sweating can itself create anxiety and social stress, and persistent symptoms deserve appropriate diagnosis.
What causes secondary hyperhidrosis?
Secondary hyperhidrosis means another factor is driving the excessive sweating. Medicines and medical conditions are principal causes. Secondary disease may be localised, asymmetric or generalised and may continue during sleep.
The clinical history—age of onset, distribution, night symptoms, medicines and associated health changes—helps determine which causes need investigation.
Medical conditions associated with excessive sweating
Endocrine & metabolic
Diabetes, menopause and an overactive thyroid can be associated with generalised excessive sweating.
Neurological conditions
Parkinson disease, stroke, peripheral or spinal nerve damage and other neurological disorders can alter sweating patterns.
Cardiorespiratory disease
Some cardiovascular conditions and respiratory failure can produce increased sweating as part of a broader illness.
Other systemic illness
Fever and some cancers can cause increased or night sweating, usually alongside other clinical features.
Can medicines cause excessive sweating?
Yes. Drug-induced hyperhidrosis is a recognised form of secondary sweating. Medicines can affect sweating through the brain, spinal thermoregulatory centres, sympathetic pathways or directly at the sweat-gland nerve junction.
Examples can include some antidepressants, corticosteroids, cholinesterase inhibitors and opioids, among others.
Why night sweating is an important clue
Primary focal hyperhidrosis usually settles during sleep. Sweating that regularly soaks sleepwear or bedding, particularly when it begins recently, is therefore less typical of primary focal disease.
Night sweating has many possible causes and is not diagnostic of any one illness. It should be interpreted together with fever, weight change, medicines, hormonal symptoms and other health information.
Why do the palms, soles and underarms sweat so much?
Eccrine sweat glands are found throughout the body but are particularly numerous on the palms and soles. Primary focal hyperhidrosis commonly affects these sites as well as the underarms and face or scalp.
Palmar sweating can interfere with writing, phones, keyboards, tools and handshakes, while plantar sweating can contribute to wet footwear, odour and skin problems.
How is the cause of excessive sweating diagnosed?
A dermatologist asks when sweating started, where it occurs, whether both sides are affected, whether it happens during sleep, family history, medicines and how much it interferes with daily life.
Primary hyperhidrosis is usually diagnosed clinically. When secondary generalised sweating is suspected, investigations are selected according to symptoms and possible causes.
When should excessive sweating be checked?
Arrange medical assessment when sweating begins suddenly, is generalised rather than focal, occurs during sleep, affects only one side, or starts after a new medicine. Associated fever, unexplained weight loss, palpitations, chest symptoms, tremor or other new symptoms also warrant evaluation.
If the pattern is longstanding focal sweating of the palms, soles or underarms, treatment can still make a substantial difference to daily life. Options are selected according to the affected area and severity.
For assessment and treatment, visit Hyperhidrosis Treatment in Chennai. For sweaty palms and feet, Iontophoresis Treatment in Chennai is one option used in appropriate patients.
Frequently asked questions
What causes excessive sweating?
Excessive sweating can be primary hyperhidrosis, caused by overactive nerve signals to sweat glands, or secondary hyperhidrosis caused by a medical condition, medication or other identifiable factor.
Can anxiety cause excessive sweating?
Anxiety and emotional stress can trigger or worsen sweating, particularly in primary focal hyperhidrosis, but persistent excessive sweating should not automatically be attributed to anxiety.
Why do my hands and feet sweat so much?
Symmetrical excessive sweating of the palms and soles that begins in childhood or adolescence and reduces during sleep is a typical pattern of primary focal hyperhidrosis.
Can medicines cause excessive sweating?
Yes. Several medicines can cause secondary hyperhidrosis. A clinician should review medication timing and alternatives rather than the patient stopping prescribed medicine suddenly.
When should excessive sweating be medically assessed?
New generalized sweating, night sweating, one-sided or asymmetric sweating, or sweating accompanied by fever, weight loss, chest symptoms, palpitations or other unexplained symptoms should be medically assessed.
Visit us in OMR
Sweating more than your body needs? Find out which type of hyperhidrosis you have.
Book a dermatologist consultation at Ram Skin Clinic in Thoraipakkam, Chennai.
#48, Second Floor, Flat E, Best Towers,Okkiampet, Thoraipakkam, OMR,
Chennai – 600097. Above Domino’s Pizza.
