What Causes Palmar Hyperhidrosis?
Palmar (hand) hyperhidrosis is caused by a condition called primary focal hyperhidrosis (PFH). It is the most common type of hyperhidrosis and it is a lifelong condition, but hyperhidrosis may get better with age. Hyperhidrosis is fairly common, as about 3% of the population is thought to have it. Symptoms usually appear between the ages of 14 and 25, although some people experience symptoms much earlier. In fact, up to 88% of the people who experience symptoms before the onset of puberty have either palmar or plantar (foot) hyperhidrosis, or both. Palmar sweating is just one manifestation of PFH and it can also affect the feet, armpits, face, and occasionally other areas of the body. One retrospective chart review found that 25% of the people with hyperhidrosis had both palmar and plantar involvement while only 6% had only palmar involvement. That means that most people with palmar hyperhidrosis also have excessive sweating on another part of their body. So, what causes primary focal hyperhidrosis?
The Causes of Primary Focal Hyperhidrosis
There are several factors that play a role in the development of primary focal hyperhidrosis, but the causes of the disorder are not well understood. It is thought that hyperhidrosis is a hereditary condition. This is especially true in the case of palmar hyperhidrosis. One study of families with palmar hyperhidrosis found that 65% of patients had other family members with the disorder. This is significant because it shows that palmar hyperhidrosis is likely to have a genetic link. Getting hyperhidrosis at an earlier age, which is often associated with palmar involvement, was shown to correlate with a positive family history of the disorder - meaning that there may be a genetic component. So, it is suspected that palmar hyperhidrosis may be caused by genetics, at least in part. However, more research needs to be done in order to determine how much genetics play a role in the development of hyperhidrosis.
Primary focal hyperhidrosis may be caused by genetics and other unknown factors, but that does not explain the physiological issue that causes people with hyperhidrosis to sweat excessively from their hands. The sweat glands of people with hyperhidrosis are morphologically the same as an average person, and they have the same number of sweat glands on their body, but their sweat glands are overactive. This is thought to occur due to dysfunction of the autonomic nervous system, which is responsible for bodily functions that are not consciously controlled, like breathing. There are two main parts of the autonomic nervous system: the sympathetic nervous system and the parasympathetic nervous system. The sympathetic nervous system is responsible for activating what is known as the “fight or flight” response, while the parasympathetic nervous system is responsible for calming bodily functions down. Sweat glands are activated by the sympathetic nervous system, so if a person’s sympathetic nervous system is overactive then it makes sense that they might have overactive sweat glands. Some studies have found differences in parts of the sympathetic nervous systems of people who have hyperhidrosis. More research needs to be done in order confirm that this is the cause of PFH, but it is a promising lead.
While future research and treatments are being developed, there is currently no cure for hyperhidrosis. There are, however, effective treatments for for sweaty hands. By using the treatments that are available people with palmar hyperhidrosis can learn to manage their symptoms and minimize the impact hyperhidrosis has on their life.
- Pariser, D. M. (2014). Hyperhidrosis (4th ed., Vol. 32). Philadelphia, PA: Elsevier.
- Huddle, J. R. (2014). Hyperhidrosis: Causes, Treatment Options and Outcomes. New York, NY: Nova Science.