In the past, there was little data on the prevalence of primary hyperhidrosis (Hh). Recently, however, more studies have been published in the medical literature - with illuminating statistics:
- Archives of Dermatological Research (2016): Researchers reported the prevalence of hyperhidrosis in the United States as 4.8%, representing approximately 15.3 million people. That’s almost twice as many people as previously believed1a and this makes Hh more common than autism, melanoma, psoriasis, and peanut allergies.1b-1e In the study, the prevalence rate was shown to be highest among 18–39 year olds (8.8%) and lowest among children/adolescents (2.1%).
- Dermatology (2016): A study showed that, in Sweden, prevalence of primary hyperhidrosis was 5.5% with severe, primary hyperhidrosis affecting 1.4% of the population. Secondary hyperhidrosis was observed in 14.8% of the study participants.
- PLoSOne (2016): Research results found that the prevalence of primary hyperhidrosis among dermatology outpatients in Shanghai was 14.5% and in Vancouver was 12.3%.
- Dermatologic Surgery (2016): Data showed that multifocal hyperhidrosis is common with 81% of patients reporting three or more hyperhidrotic sites.
- American Academy of Dermatology Annual Meeting (2017): Data presented as an abstract on "pediatric breaking news" showed that 17.1% of teens surveyed experience excessive, uncontrollable sweating based on published diagnostic criteria.
The above statistics are key updates on older research, which has been frequently cited:
- 1976: An Hh incidence of 0.6% to 1.0% in a young Israeli population (pilot epidemiology study reported by Adar and colleagues) 
- 2003: A consumer survey of a nationally representative sample of 150,000 households in the U.S. screened for the presence of hyperhidrosis. Results showed that the prevalence of hyperhidrosis in the U.S. was 2.8% (7.8 million Americans). Of those with hyperhidrosis, only 38% consulted their physician about their excessive sweating..
Recent research (from 2016 and 2018) expands upon the above older data regarding long delays among sufferers in discussing Hh with a healthcare professional (HCP) and in receiving care:
- 85% waiting 3+ years to discuss excessive sweating with an HCP and 50% waiting 10+ years to do so.2a
- 27% never receiving diagnosis.1a
- Among Hh sufferers who had not received any hyperhidrosis treatment, 38.5% said they were "not sure why not."2a
Regarding a genetic link and hyperhidrosis:
- Recent data (2018) found that 18% of Hh sufferers report an immediate family member also suffering from excessive sweating.2a
- A series of studies on patients treated by endoscopic thoracic sympathectomy (ETS) reported a family history in 35% and 56% of participants.[35,82]
- A study of the familial aggregation of hyperhidrosis also suggested that the disorder may be more common than previously thought. When family history was analyzed in a group of patients with primary hyperhidrosis, 65% of patients reported a family history compared to no family history in controls. On the basis of these findings, the disease allele is present in 5% of the population, with an observed penetrance of 25%. The researchers (Ro and colleagues) concluded that because many of those with hyperhidrosis are reluctant to seek treatment, the previously reported incidence may be “a gross underestimation.”
Focal primary hyperhidrosis usually has an onset during childhood or adolescence.
- Data published in 2016 found that: 1) the majority of palmar and plantar (66% and 61%, respectively) primary hyperhidrosis patients reported childhood onset (less than 12 years). 2) 36% of respondents reported that their primary axillary hyperhidrosis started before the age of 12 years.3a
- This 2016 study also showed that hyperhidrosis is often a lifelong struggle with symptom severity FAILING to lessen with age -- 88% reported that symptoms have become worse or stayed the same over time. 3a
- In a series of Taiwanese patients with palmar hyperhidrosis (1997), 75% had childhood onset, with the remainder presenting during puberty. 
- In a study of 850 patients (2002) with palmar, axillary, or facial hyperhidrosis, 62% said they had the symptoms “…as long as they could remember,” 33% said the onset occurred during puberty, and 5% reported their first symptoms as adults.
- Hölzle from Germany (2002) states that primary hyperhidrosis starts in puberty, peaks in the third and fourth decade, but can be seen in childhood and even infancy.
- In the 2003 U.S. consumer survey (noted above), the average age at onset was 25 years, but varied with location of hyperhidrosis. The average age of onset for those with palmar or axillary symptoms and symptoms in one other location was 22 years, for those with axillary alone age of onset was 19 years, and for those with palmar alone age of onset was 13 years.
Prevalence of the types of primary hyperhidrosis based on body location has been reported in numerous studies:
- In 2016, results from 1,985 survey participants showed that axillary hyperhidrosis was the most prevalent type of hyperhidrosis in the study sample (68%) followed by palmar (65%) and plantar (64%). More than 30% of survey respondents reported craniofacial, groin, or inframammary hyperhidrosis.3a
- In 256 German patients reported by Hölzle, 115 had excessive sweating in the axillae, 86 on the palms, and 75 on the soles.
- In a series of 382 French patients treated with ETS, 30% had palmar and plantar hyperhidrosis, 51% had palmoplantar and axillary hyperhidrosis, 6% had palmoplantar and facial hyperhidrosis, 5% had all areas involved, and 8% had axillary hyperhidrosis only.
- According to the 2003 U.S. consumer survey, 51% of hyperhidrosis patients have axillary hyperhidrosis alone or in combination with hyperhidrosis in another location, 9.5% have axillary hyperhidrosis alone, 25% have palmar hyperhidrosis alone or in combination with hyperhidrosis in another area, and only 1% have palmar hyperhidrosis alone.
Multifocal is most common:
It should be noted here, again, the primary focal Hh is most typically a multifocal disease. Glaser and colleagues in 20163a found that:
- 81% of those with axillary Hh have three or more other sites also affected
- 46% of those with axillary Hh have four or more other sites affected.
Results also indicated that primary hyperhidrosis is not solely dictated by the season with 65% of patients reporting that their sweating bothers them equally throughout the year.3a
Key take-aways: primary Hh is relatively common, multifocal, and chronic with an onset in youth and an apparent genetic link -- yet, diagnosis and treatment is often delayed for years.
1a. Doolittle J, Walker P, Mills T, Thurston J. Hyperhidrosis: an update on prevalence and severity in the United States. Archives of Dermatological Research. 2016;308(10):743-749. doi:10.1007/s00403-016-1697-9.
1b. Key statistics for melanoma skin cancer. American Cancer Society website. https://www.cancer.org/cancer/melanoma-skin-cancer/about/key-statistics.html. Jan. 4, 2018. Accessed April 18, 2018.
1c. How common is psoriasis worldwide? NEJM Journal Watch website. https://www.jwatch.org/jd201211090000002/2012/11/09/how-common-psoriasis-worldwide. Nov. 9, 2012. Accessed April 18, 2018.
1d. Food allergy facts and statistics. Food Allergy Research & Education website. https://www.foodallergy.org/sites/default/files/migrated-files/file/facts-stats.pdf. Accessed April 18, 2018.
1e. Autism Spectrum Disorder (ASD) Data & Statistics. Centers for Disease Control and Prevention website. https://www.cdc.gov/ncbddd/autism/data.html Feb. 12, 2018. Accessed April 19, 2018.
2a. Glaser DA, Hebert A, Pieretti L, Pariser D. Understanding Patient Experience with Hyperhidrosis: A National Survey of 1,985 Patients. Journal of Drugs in Dermatology. 2018 17(4):392-396.
3a. Glaser DA, Ballard AM, Hunt NL, Pieretti LJ, Pariser DM. Prevalence of Multifocal Primary Hyperhidrosis and Symptom Severity Over Time: Results of a Targeted Survey. Dermatol Surg. 2016 Dec;42(12):1347-1353.