Article

Excessive Sweating (Hyperhidrosis): Causes, Symptoms and Treatments
February 05, 20190782

What is hyperhidrosis?

Hyperhidrosis is a skin disorder in which more sweat is made than is needed to keep a steady body temperature.1,2

Hyperhidrosis may severely decrease your quality of life. It can cause embarrassment, emotional stress and social anxiety. It may ruin your ability to live your life normally. You may find it difficult to go to work. It may keep you from spending time with friends and family.3

Constant moisture also makes the skin more prone to infections.4

Causes of Hyperhidrosis

Scientists believe that the root cause of excess sweating is abnormal signaling by the sympathetic nervous system.3,4

Normally, the sympathetic nervous system increases sweat production during the “flight-or-flight” response.

In people with hyperhidrosis, this system stops working correctly.4 For some reason, activation of the sympathetic nervous system by stress causes too large of a response by sweat glands.

 

Figure 1: Diagram of the sympathetic nervous system (Shutterstock/Alila Medical Media)

For some cases of hyperhidrosis, doctors can figure out what is causing the nervous system to behave oddly. This is diagnosed as secondary hyperhidrosis.4

In many cases, however, it is unclear why a person is experiencing excessive sweating. This is called primary hyperhidrosis.3,4

 

Primary hyperhidrosis

Primary hyperhidrosis is idiopathic. This means that doctors do not fully understand what causes it.3

Studies show that primary hyperhidrosis is at least partially genetic. Between 35 and 56 percent of those diagnosed with primary hyperhidrosis have at least one family member with it.2

Looking at family trees, it appears that hyperhidrosis is an autosomal dominant condition.2 This means, for example, that if either of your parents have primary hyperhidrosis, there is a 50 percent chance that you inherited it. The risk is the same for men and women.

 

Figure 2: Diagram of autosomal dominant inheritance (Shutterstock/Meletios)

 

It seems that excessive sweating is not caused by a single gene mutation.5

Scientists found the gene responsible for excessive sweating in some people. However, this mutation cannot be found in everyone with hyperhidrosis.5 This means other genes must be able to cause it as well.

Any genes found to play a role in causing hyperhidrosis are likely to be important in controlling brain function. Changes in the function of the cortex are most likely to be the root cause of this condition.3

Secondary hyperhidrosis

Secondary hyperhidrosis is excessive sweating for which doctors can find a cause.

There are many things that may harm normal nerve function. Among the most common of these are2,3:

  • Medications
  • Drugs
  • Contact with toxins
  • Hyperthyroidism
  • Diabetes
  • Heart failure
  • Pregnancy
  • Gout
  • Cancer
  • Obesity
  • Parkinson’s disease
  • Infection
  • Rheumatoid arthritis
  • Stroke
  • Spinal cord injury
  • Large burns
  • Abnormal function of the hypothalamus
  • Abnormal function of the pituitary
  • Genetic disorders

 

How common is hyperhidrosis?

Depending on the country, rates of hyperhidrosis have been found to be between 0.5 and 3 percent.2,3,6

It is believed that over 90 percent of cases are primary hyperhidrosis.1

 

Symptoms of Hyperhidrosis

Primary Hyperhidrosis

The main symptom of primary hyperhidrosis is chronic excessive sweating.1-6

The sweating is usually confined to areas with a lot of sweat glands, such as2-4:

  • armpits
  • palms of the hands
  • bottoms of the feet

Sometimes, you may have sweating on the face or scalp. In rare cases, you may have sweating around the glutes or upper thighs.2,3

The sweating occurs during the day.3,4

The sweating is equally intense on both sides of the body.4

In primary hyperhidrosis, sweating is usually worse when you are emotionally upset. It can also become worse when you are exercising or in a warm environment.3

Usually, if you have primary hyperhidrosis, you will begin seeing symptoms in childhood. Symptoms almost always begin before the age of 25.4

You may have other symptoms related to changes in your nervous system. These may include5:

  • Fingers and toes turning white in response to cold or stress
  • Dizziness upon standing
  • Fainting upon standing
  • Abnormal changes in heart rate during stress or exercise

If these symptoms appear, and how severe they are, likely depend on your exact gene mutation.

Secondary hyperhidrosis

The symptoms of secondary hyperhidrosis depend on the root cause.

Generally, sweating in secondary hyperhidrosis is more widespread than in primary hyperhidrosis. You may have sweating on the head, neck, back or stomach, legs, glutes or your wrists.2

With secondary hyperhidrosis, you can have sweating on just one side of the body.4

Usually, symptoms of secondary hyperhidrosis begin later in life (after 25 years of age).4

If you have secondary hyperhidrosis, you are likely to sweat more at night or while you are sleeping.2

 

Diagnosis of Hyperhidrosis

Primary hyperhidrosis

Doctors use specific guidelines to diagnose primary hyperhidrosis.4

Diagnosis is based almost solely on your medical history. If you see a doctor about profuse sweating, you will be asked a lot of questions about your health.

If your symptoms meet the criteria listed below, you may be diagnosed with primary hyperhidrosis.2,4

  1. Symptoms have lasted longer than 6 months
  2. Sweating occurs at least once per week
  3. Sweating is in the armpits, on the palms of the hands or on the bottoms of the feet
  4. Both sides of the body sweat
  5. Sweating impairs normal daily activities
  6. Sweating does not occur at night
  7. Sweating began before the age of 25
  8. Other members of your family have hyperhidrosis

 

Secondary hyperhidrosis

Diagnosing secondary hyperhidrosis is also based mostly on medical history.1

You may be diagnosed with secondary hyperhidrosis if4:

  • You were over 25 years old when your symptoms began
  • Only one side of the body sweats profusely
  • Sweating is in areas of the body other than armpits, palms, feet or face
  • Symptoms occur at night

Your doctor may also diagnose you with secondary hyperhidrosis if your medical history includes a disorder or medication known to cause excessive sweating.

 

Table 1: List of criteria that help doctors choose between primary and secondary hyperhidrosis

 

Treatment of Hyperhidrosis

Primary hyperhidrosis

Since doctors do not know the cause of primary hyperhidrosis, treatment is focused on controlling the symptoms.

There are five classes of treatments for excessive sweating. Which one(s) your doctor chooses to use depends mostly on what part of your body is affected.4

However, your treatment also depends on:

  • how much your symptoms respond to each treatment
  • if you have side effects
  • how well you handle individual treatments

 

Figure 3: Common order of treatment for excessive sweating in different areas of the body.4

“1” is the treatment used first. “4-5” are only used in severe cases.

 

Topical creams

For most cases of excessive sweating, skin creams are the first line of treatment.4

These creams usually contain either aluminum chloride or glycopyrrolate.3

Aluminum chloride

Aluminum chloride is the active ingredient in normal antiperspirants.

It is not clear how aluminum chloride stops sweating. It is thought it may damage sweat glands and keep them from working.4

If your symptoms are mild, over-the-counter antiperspirants may be able to stop your sweating.4

If your symptoms are more severe, you may need prescription strength aluminum chloride. This is usually given as 20 percent aluminum chloride in ethanol or salicylic acid.4

This solution is applied to the affected areas before bed. Most people see a decrease in sweat within one or two weeks.4

Side effects of Aluminium Chloride

Around a quarter of people have skin reaction to aluminum chloride.4 This seems to happen less when the medication is in salicylic acid, rather than in alcohol.4

If irritation occurs, your doctor may prescribe a 1 percent hydrocortisone cream.4 If this does not heal your skin, you may be switched to a different treatment.

Glycopyrrolate

Glycopyrrolate is the other common topical agent.

It is usually given at doses of 0.5, 1 or 2 percent. It can be used every day or every other day.4

Glycopyrrolate works by stopping signaling from nerves to sweat glands in affected areas.3

This treatment is usually effective.4

Side effects of Glycopyrrolate

Glycopyrrolate rarely has any side effects.4

Oral medications

If topical creams are not working well, your doctor may prescribe a pill.

There are two classes of drugs commonly prescribed: anticholinergic agents and alpha-adrenergic agonists.

Anticholinergic agents

These medications work by preventing signals from the sympathetic nervous system from reaching the sweat glands.3 The most common drugs and their dosages are listed below.3

 

Table 2: Common doses of oral medications used to treat excessive sweating

MedicationDoseFrequency
Glycopyrrolate1-2 mg2x per day
Menthatheline bromide50 mg2x per day
Oxybutynin5-7.5 mg2x per day

 

Side effects

Since these drugs are taken by mouth, they affect the sympathetic nervous system in the whole body, not just in the skin. This causes them to have unwanted side-effects, including3:

  • Dry mouth
  • Blurry vision
  • Trouble urinating
  • Slow heart beat
  • Confusion

Reasons not to use oral medications

If you have certain problems with your eyes, bladder, muscles, digestive tract or heart, these medications may not be right for you.3 Your doctor may choose to put you on a lower dose or not give you these medications at all.

Conditions that might keep you from being given these medications include3:

  • Glaucoma
  • Narrow angle glaucoma
  • Difficulty peeing
  • Heart failure
  • Myasthenia gravis
  • Acid reflux
  • Pyloric stenosis

 

Alpha-adrenergic agonists

These drugs work by sending extra signals through nerves that are not part of the sympathetic nervous system. This tricks the sweat glands into thinking there are fewer signals coming from the sympathetic nervous system.3

Only one kind of alpha-adrenergic agonist is given by doctors to treat excessive sweating. It is called clonidine.

Clonidine is taken as a 0.1 mg pill twice per day.3

Side effects of Clonidine

Side effects of clonidine include3:

  • Dry mouth
  • Dizziness
  • Constipation
  • Sleepiness
  • Low blood pressure

 

 

Iontophoresis

Iontophoresis is a treatment where small molecules are helped into your skin by a weak electric current.4 It is not clear how this works to stop sweating. Scientists think it might change how the sweat glands handle salt. Since salt is an important part of sweat, this may change how much sweat the glands can make.4

Water

Iontophoresis is often done with simple tap water.3,4

Your doctor may have you buy a machine that can perform iontophoresis with tap water. You can use this machine at home, by yourself.4

At first, you will likely have to use it for 10 minutes every two or three days. After about two weeks, you should be able to reduce your number of treatments to once a week or once every two weeks.4

Glycopyrrolate

Doctors can use iontophoresis to get glycopyrrolate cream deeper into your skin. This can lead to better control of your symptoms.4

Botulism toxins

Occasionally, doctors will use iontophoresis to get botulism toxins into your skin. Botulism toxins are powerful nerve blocking agents.

Iontophoresis is not an efficient way to get botulism toxins into the skin because they are large molecules. Some people still prefer iontophoresis to shots, though, because it is less painful.3

Adding botulism toxin to your iontophoresis treatment can increase the time you can wait between treatments to up to 3 months.3

Side effects of iontophoresis

The electric current from this treatment can cause a burning or tingling sensation.3,4 It may make the treated area turn red.3 You may find the treatment is uncomfortable, but most people do not find it painful.3

Reasons not to use iontophoresis

Your doctor will likely not prescribe this treatment for you if you3:

  • have a metal plate holding bones together
  • have had a joint replaced
  • have a pace-maker
  • are pregnant

 

Injections

A common treatment for excessive sweating is injection of botulism toxin under the skin.

As mentioned above, botulism toxins are powerful compounds that prevent signals from the nerves to the sweat glands.

To make sure the whole area stops sweating, doctors inject the toxins in multiple spots. Usually, the shots are arranged in grid-like pattern to make sure no areas are missed.3

The injections are done with a tiny needle.3

With each shot, small amounts of toxin (2 to 2.5 units) are injected a few millimeters under the skin.3

 

Figure 4: Grid for injecting botulism toxin to treat excess sweating on the palm of the hand.3

(modified from Shutterstock/Cat_arch_angel)

 

Doctors numb the area 1 to 2 hours before treatment. Some doctors add more numbing cream or spray directly before treatment.3

Shots of botulism toxin are effective. Between 80 and 90 percent of people see improvements in their symptoms.3

Decreases in sweating usually last between 3 and 8 months. You only need a few treatments per year.3

Side effects

You may experience mild side effects of botulism shots. These include3:

  • pain at the injection sites
  • decreased muscle strength in the treated area
  • upset stomach
  • dry mouth

 

Reasons not to get injections

You may not be able to get shots of botulism toxin if you have any of the following conditions3:

  • ALS
  • Lou Gehrig’s disease
  • Lambert Eaton Syndrome
  • myasthenia gravis
  • problems swallowing
  • problems breathing

 

Surgery

If your symptoms are not improving with other treatments, you doctor may decide to do surgery.

Local Surgery

For excess sweating in the armpits, local surgeries can be done. In these surgeries, doctors remove sweat glands from the armpit. This surgery only requires local numbing.4

Side-effects of Local Surgery

Usually, side effects of local surgeries are limited to local pain, swelling and bruising. Sometimes people also experience4:

  • scarring
  • tingling or numbness
  • hair loss in the armpit

Sweating symptoms return in about 15 percent of people.4

Nerve Surgery

In the most severe cases of excessive sweating, nerve surgery may be done.

This surgery requires full anesthesia.

During this surgery, the surgeon makes between one and three small cuts in order to reach the nerves. He locates the nerves where they leave the spinal cord and removes, clamps off or burns the nerves responsible for the sweating.4

Nerve surgery is done almost solely for excess sweating of the palms. This is because stopping sweating on the hands requires destroying only one nerve.  This is the nerve located between the T-2 and T-3 vertebra.4

Stopping sweating on the bottom of the feet can be done by destroying the nerve at the L-3 vertebra. Doctors rarely do this because it can easily cause loss of sexual function.4

Nerve surgery to prevent sweating in the armpits is almost never done. It requires removing all the nerves from the T-3 through the T-6 vertebra. This can have serious side effects.4

Side effects of Nerve Surgery

The most common side effects of nerve surgery are pain, swelling and bruising around the incisions.4

Between 35 and 100 percent of people experience “compensatory hyperhidrosis”.  This is when new areas of the body begin to sweat excessively after surgery.4 Usually, this is in the lower parts of the body, such as legs or glutes.3

In rare cases, the surgery may result in damage to the lungs or blood vessels to the brain.3,4 Both of these complications can be life-threatening. They require immediate medical attention.

 

Secondary hyperhidrosis

The first line of treatment for secondary hyperhidrosis is to treat the cause.

In some cases, this is easy. For example, if excess sweating is found to be caused by a medication, the treatment is to stop the medication.

For excessive sweating caused by chronic conditions (such as diabetes or gout), the treatment goal is to control the original condition. If needed, your doctor may also prescribe one of the treatments described above to control your sweating symptoms.

For permanent conditions (such as spinal cord injury or stroke damage) the goal is to minimize sweating symptoms. Your doctor will likely prescribe one of the treatments described above.

 

Hyperhidrosis FAQs

  • Why do I sweat so much?

It is hard to say why you are sweating so much.

It may be that your body is working hard to keep you from getting too warm. This is likely if you sweat a lot when you are somewhere hot or are exercising.

You may, however, have a medical disorder in which you sweat more than you need to. This is likely if1,3,4:

  • sweating only happens in certain parts of your body (palms, armpits, feet or face)
  • sweating is worse when you are stressed than when you are too warm
  • sweating only occurs during the day or only at night
  • someone else in your family sweats a lot
  • the sweating often interferes with your life

If you have these symptoms, you should see a doctor. Sweating more than you need to may be a symptom of other diseases.

  • How do you stop sweating so much?

If you are diagnosed with excessive sweating, there are many treatments available that may help you sweat less. These include3,4:

  • skin creams and treatments
  • pills
  • shots
  • surgeries
  • Is excessive sweating a disease?

Sweating more than you need to keep your body a constant temperature is considered a disease. This disease is called hyperhidrosis.1-6

If you are concerned about how much you sweat, you should see a doctor to determine if you have hyperhidrosis.

  • Can excessive sweating be a sign of cancer?

Yes. Some forms of cancer can cause profuse sweating.2,3 If your sweating began suddenly and without any clear cause, please see a doctor.

 

References

  1. Walling HW. Clinical differentiation of primary from secondary hyperhidrosis. Journal of the American Academy of Dermatology. 2011;64(4):690-695.
  2. Moraites E, Vaughn OA, Hill S. Incidence and prevalence of hyperhidrosis. Dermatologic clinics. 2014;32(4):457-465.
  3. Lakraj AA, Moghimi N, Jabbari B. Hyperhidrosis: anatomy, pathophysiology and treatment with emphasis on the role of botulinum toxins. Toxins. 2013;5(4):821-840.
  4. Walling HW, Swick BL. Treatment options for hyperhidrosis. American journal of clinical dermatology. 2011;12(5):285-295.
  5. Del Sorbo F, Brancati F, De Joanna G, Valente EM, Lauria G, Albanese A. Primary focal hyperhidrosis in a new family not linked to known loci. Dermatology. 2011;223(4):335-342.
  6. Vorkamp T, Foo FJ, Khan S, Schmitto JD, Wilson P. Hyperhidrosis: evolving concepts and a comprehensive review. The surgeon : journal of the Royal Colleges of Surgeons of Edinburgh and Ireland. 2010;8(5):287-292.

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