Hyperhidrosis: causes, symptoms, and treatment

Mike Bohl, MD, MPH, ALM - Contributor Avatar

Written by Chimene Richa, MD 

Mike Bohl, MD, MPH, ALM - Contributor Avatar

Written by Chimene Richa, MD 

last updated: Dec 16, 2019

4 min read

Hyperhidrosis is a medical condition characterized by excessive sweating. Sweating is a necessary and natural response to an increase in body temperature; several things can trigger sweating, including warm temperatures, exercise, or situations that make you angry, embarrassed, nervous, or afraid.

When your body senses a rise in temperature, it triggers your autonomic nervous system (sympathetic nerves) to help you cool off; the neurotransmitter (brain chemical) acetylcholine stimulates your sweat glands to release sweat. When the sweat reaches your skin, it evaporates and cools you down.

In hyperhidrosis, you sweat more than usual and often without the typical triggers. One theory to explain hyperhidrosis is that there may be an abnormally increased release of acetylcholine, or that the nerve signals cannot be turned off appropriately. It is unclear exactly how many people suffer from this condition because it often goes unreported; many people don’t realize that this is a medical problem, or that it is treatable, and never mention it to their healthcare provider. Current estimates of the prevalence of hyperhidrosis in the United States are 15.3 million people, or approximately 4.8% of the population (Doolittle, 2016).

There are two types of hyperhidrosis: primary focal hyperhidrosis and secondary generalized hyperhidrosis. Primary hyperhidrosis is not caused by another medical condition or medications that you may be taking; excessive sweating is the medical condition. It usually focuses on specific parts of the body like hands (palmar hyperhidrosis), feet (plantar hyperhidrosis), underarms (axillary hyperhidrosis), and face/head (craniofacial hyperhidrosis). In fact, the hands are affected in over half of people with primary hyperhidrosis (Brackenrich, 2019). However, the increased perspiration can also affect more than one focal area, like hands and feet (palmoplantar hyperhidrosis).

Primary hyperhidrosis usually occurs equally on both sides of the body (symmetric sweating) and typically begins in childhood or adolescence. These episodes often occur at least once a week and rarely during sleep. Lastly, most people with primary focal hyperhidrosis also have a family member with excessive sweating.

Secondary hyperhidrosis differs because it is excessive sweating that is caused by a medical condition, such as hyperthyroidism, diabetes, or menopause; it can also be due to medication side effects. People with this type of hyperhidrosis have increased sweating in larger areas, also called "generalized" areas, of the body; some people complain of sweating “all over.” Another difference is that secondary hyperhidrosis usually starts in adulthood. Lastly, excessive sweating may occur while sleeping (night sweats), which is not often the case in primary hyperhidrosis.

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Causes of hyperhidrosis

In primary focal hyperhidrosis, there is no specific cause. As mentioned above, the theory is that there is a problem with the nervous system stimulation of sweat glands; people with excessive sweating may have a problem with the signals to turn the sweating response off, leading to increased sweating. Secondary hyperhidrosis, by definition, is caused by a specific condition or side effect of a medication. Potential medical conditions that cause this include (Romero, 2016):

  • Hyperthyroidism

  • Diabetes

  • Menopause (hot flashes)

  • Pregnancy

  • Parkinson’s disease

  • Nerve injury

  • Chronic lung disease

  • Cancer

  • Tuberculosis

  • Human immunodeficiency virus (HIV)

Also, several drugs have excessive sweating as a potential side effect; these drugs include (McConaghy, 2018):

Signs and symptoms of hyperhidrosis

Other than having excessive sweating, the International Hyperhidrosis Society advises that you may have primary focal hyperhidrosis if you have visible excessive sweating for more than six months plus at least two of the following criteria:

  • Sweating the same on both sides of your body

  • Having an episode of excessive sweating at least once per week

  • Increased sweating that started before age 25

  • Other members of your family have similar sweating problems

  • No sweating during sleep

  • Excessive sweating affects your daily activities

Also, excessive sweating can cause significant psychological distress as well as skin breakdown or infection from chronic wetness.

Secondary generalized hyperhidrosis can sometimes cause excessive sweating all over or in a large area of the body; it is also more likely to occur during sleep.

Diagnosis of hyperhidrosis

The diagnosis of hyperhidrosis starts with a physical exam, especially looking at the areas of the body that experience excessive sweating. Your healthcare provider or dermatologist will also ask you specific questions to help understand why you have profuse sweating. Some people need additional information from sweat tests, which may include the starch-iodine test, thermoregulatory test, and paper test.

In a starch-iodine test, an iodine solution is applied to the areas of concern and allowed to dry. The dry starch is sprinkled on top of the iodine; if you sweat, the moisture allows the starch and iodine to mix, and the color changes from yellow to dark blue. Similarly, in the thermoregulatory test, the affected areas are coated with a powder that changes color when it comes in contact with sweat (changes from yellow to dark blue/purple); you may be asked to sit in a warm room to encourage sweating. People with hyperhidrosis will sweat more than average. Lastly, a special kind of paper is placed in sweaty areas, like your underarms, and then weighed after a time to see how much sweat was absorbed.

If your provider suspects that a medical condition is causing your hyperhidrosis, you may need additional blood or urine testing.

Treatment for hyperhidrosis

Several different treatments and medications are available to help alleviate hyperhidrosis. You should discuss the risks and benefits with your provider to determine which one is right for you.

OC Hyperhidrosis: causes, symptoms, and treatment image d77d7496-63c1-4b73-99e3-b68f5cfbf2ec

In cases of secondary hyperhidrosis, addressing the underlying cause of excessive sweating may reduce your symptoms.

In conclusion

Hyperhidrosis can cause anxiety and make you feel embarrassed. Some people avoid social situations or try to hide the sweating under layers of clothing. If you are concerned that you may be sweating more than you should be, talk to your healthcare provider. Treatments are available; you need to find one that is right for you so that you can get back to living life.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

December 16, 2019

Written by

Chimene Richa, MD

Fact checked by

Mike Bohl, MD, MPH, ALM

About the medical reviewer

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.