Hyperhidrosis

Hyperhidrosis means sweating more than your body needs to control its temperature. The sweating may soak clothing, drip from the hands, make feet slide in shoes, or interfere with everyday tasks.

Sweat itself is normal. It cools the body during heat, exercise, fever, or physical work. Hyperhidrosis is different because sweating can happen when you are resting, in a cool room, or without an obvious trigger.

There are two main types.

Primary focal hyperhidrosis affects particular areas, usually both sides of the body. Common sites include the underarms, palms, soles, face, and scalp. It often begins during childhood or the teenage years. No other illness or medicine explains it.

Secondary hyperhidrosis is caused by another health condition, a medicine, or a substance such as alcohol. It may affect most of the body and can begin suddenly. Sweating during sleep is more likely with this type.

Hyperhidrosis is not usually physically dangerous. However, it can affect work, school, sleep, relationships, clothing choices, and emotional well-being. Effective treatments are available, although finding the right option may take time.

The main symptom is visible or troublesome sweating that is out of proportion to heat or activity.

Depending on the area involved, you may notice:

• Clothing becoming wet around the underarms, back, chest, or groin
• Sweat dripping from the hands or making it hard to grip objects
• Damp feet, soaked socks, or shoes wearing out quickly
• Sweat running down the face or scalp
• Skin becoming pale, soft, cracked, or irritated from staying wet
• Avoiding handshakes, certain clothes, social events, or close contact

Primary focal hyperhidrosis is usually symmetrical. For example, both palms or both underarms are affected. Episodes often happen at least weekly and usually stop during sleep. Heat, exercise, stress, spicy food, and caffeine may make the sweating worse, but episodes can occur without a clear trigger.

Secondary hyperhidrosis may cause sweating across large areas of the body. It may begin later in life, happen during sleep, or appear after starting or changing a medicine.

Sweat is produced by glands in the skin. These glands receive signals from the sympathetic nervous system, which controls automatic body functions.

In primary focal hyperhidrosis, the sweat glands are usually normal. The nerves controlling them appear to send stronger signals than needed. The exact reason is not fully understood.

Primary hyperhidrosis can run in families. Having a close relative with the condition increases the chance of developing it, although no single pattern applies to everyone.

Secondary hyperhidrosis has an identifiable cause. Possible causes include:

• Hormonal changes, including menopause
• An overactive thyroid
• Low blood sugar or poorly controlled diabetes
• Some infections
• Certain nervous system conditions
• Alcohol or drug withdrawal
• Medicines, including some antidepressants like sertraline or fluoxetine, pain medicines, and hormonal treatments

These causes do not all have the same likelihood. Sweating alone does not mean you have a serious underlying illness. A clinician can consider your other symptoms, medicines, and medical history.

There is no single test that confirms every case of hyperhidrosis. Diagnosis usually starts with a discussion about where, when, and how often you sweat.

You may be asked when the problem began, whether it affects both sides, whether it happens during sleep, and how it affects daily activities. A physical examination can look for sweating and skin irritation.

Primary focal hyperhidrosis is more likely when sweating:

• Has continued for at least six months without another clear cause
• Affects specific areas on both sides of the body
• Happens at least weekly
• Began before age 25
• Stops during sleep
• Runs in the family
• Interferes with everyday activities

Not everyone has every feature.

A starch-iodine test can map the sweating area by changing colour where sweat is present. Measuring the weight of sweat on absorbent material can estimate how much is produced. These tests may help plan procedures, but they are not always necessary.

If secondary hyperhidrosis is possible, tests are chosen based on your symptoms and history. These may include blood tests for thyroid function or blood sugar. A broad set of tests is not automatically needed.

Treatment depends on the body area involved, how much sweating affects you, and whether another condition is responsible.

For secondary hyperhidrosis, treating the cause or reviewing a contributing medicine may reduce sweating. Do not stop a prescribed medicine without medical advice.

Strong antiperspirants containing aluminium salts are often tried first. Unlike deodorants, which mainly control odour, antiperspirants temporarily block sweat ducts. They work best on completely dry skin and can cause stinging or irritation. Following the product instructions and treating irritation can make them easier to use.

Prescription skin treatments can reduce nerve signals to sweat glands. Some contain anticholinergic medicines, which block a chemical involved in sweating. Possible effects include dry mouth, blurred vision, skin irritation, and enlarged pupils if medicine is accidentally transferred to the eyes.

Iontophoresis is often used for sweaty hands or feet. The affected area is placed in tap water while a device passes a mild electrical current through it. Several sessions are usually needed, followed by maintenance treatment. Temporary tingling, dryness, or irritation can occur.

Botulinum toxin injections block nerve signals to sweat glands in the treated area. They can reduce underarm sweating and may also be used on the hands, feet, or face. The effect is temporary, so injections may need to be repeated. Treatment can be uncomfortable, and hand injections can sometimes cause short-term weakness.

Tablets that reduce sweating throughout the body may be considered when other approaches are unsuitable or when several areas are affected. These medicines can cause dry mouth, constipation, blurred vision, difficulty passing urine, and overheating. Because sweating helps cool the body, extra care may be needed in hot weather or during exercise.

Procedures that destroy or remove underarm sweat glands can provide longer-lasting local control. Techniques include heat-based treatment, suction, curettage, or surgical removal.

Surgery to interrupt sympathetic nerves is generally reserved for severe cases that have not responded to other treatment. It may permanently reduce sweating in the target area, but new or heavier sweating elsewhere—called compensatory sweating—is common and can be difficult to reverse.

Practical steps do not treat the underlying nerve signals, but they may reduce day-to-day problems. Breathable clothes, spare socks, absorbent shoe inserts, and rotating shoes can help manage moisture.

Constant moisture can soften and damage the skin. This may lead to soreness, cracking, eczema, body odour, or bacterial and fungal infections. Damp feet can be more prone to athlete’s foot.

The social and emotional effects can be substantial. Some people avoid touching others, speaking in public, using shared equipment, or wearing certain colours. Hand sweating can interfere with writing, electronics, tools, and musical instruments.

Hyperhidrosis may contribute to anxiety or low mood. Anxiety can also trigger more sweating, creating a cycle. This does not mean the sweating is imaginary or caused only by anxiety.

Focal sweating does not usually cause dangerous fluid loss. Extensive sweating in hot conditions can contribute to dehydration or overheating, especially if a treatment reduces your ability to sweat normally.

Primary focal hyperhidrosis cannot usually be prevented. It is linked to how the nervous system controls sweat glands, and it is not caused by poor hygiene.

You may be able to reduce episodes by identifying personal triggers. These might include heat, spicy foods, caffeine, alcohol, stress, or tight synthetic clothing. Avoiding every possible trigger is neither necessary nor always effective.

Secondary hyperhidrosis may improve when its cause is treated. Medicine-related sweating sometimes improves after a clinician adjusts the medicine or changes the treatment. Never make this change on your own.

Primary focal hyperhidrosis is often a long-term condition. It commonly starts early in life and may continue for years. Some people improve as they get older, while others continue to need treatment. It is not possible to predict the course for one person.

Most non-surgical treatments control sweating rather than permanently stopping it. Antiperspirants, iontophoresis, injections, and medicines usually require repeat or maintenance treatment. You may need to try more than one option before finding an acceptable balance between benefit, side effects, cost, and convenience.

Sweating can also change over time. One body area may become more troublesome than another, or stress, hormonal changes, weather, and medicines may alter the pattern.

Secondary hyperhidrosis may settle when the underlying cause is corrected. If the cause is ongoing, sweating may also continue.

Planning can make daily life easier. Keeping spare clothing at work or school, protecting paper and electronics, and choosing washable footwear may reduce disruption. If embarrassment or anxiety is affecting your life, psychological support can help with the impact of the condition alongside physical treatment.

Arrange a routine appointment if sweating is new, persistent, affects your daily life, or regularly wakes you from sleep. It is also worth seeking advice if over-the-counter antiperspirants have not helped or are causing significant irritation.

Prompt medical assessment is appropriate if sweating:

• Began suddenly without a clear reason
• Started after a new medicine or dose change
• Occurs with repeated fever, unexplained weight loss, or ongoing diarrhoea
• Is associated with shaking, confusion, or suspected low blood sugar
• Causes signs of dehydration, such as dizziness or very dark urine

Seek emergency help if sudden heavy sweating occurs with chest pain or pressure, severe breathing difficulty, fainting, confusion, or grey or blue skin. Sweating in this setting may be a sign of another urgent medical problem rather than hyperhidrosis itself.

Why do I sweat when I am cold?

Primary hyperhidrosis is driven by nerve signals rather than temperature alone. Your sweat glands can become active even when your body does not need cooling.

Is hyperhidrosis caused by anxiety?

Anxiety can trigger or worsen sweating, but it is not the only cause of primary hyperhidrosis. Sweating can also create anxiety, especially in social or work situations.

What is the difference between deodorant and antiperspirant?

Deodorant reduces or masks body odour. Antiperspirant reduces sweat by temporarily blocking sweat ducts. Many products contain both.

Does botulinum toxin cure hyperhidrosis?

No. It can reduce sweating in the treated area, but its effect wears off. Repeat treatment is usually needed to maintain the benefit.

Can surgery stop sweating permanently?

Surgery may permanently reduce sweating in a treated area. However, it can cause heavier sweating elsewhere and has other risks, so it is usually considered only after less invasive treatments.

Will hyperhidrosis go away on its own?

It may improve over time, but primary hyperhidrosis often continues for years. Secondary hyperhidrosis may resolve if its underlying cause is treated.