Hyperhidrosis: Symptoms, Causes and Treatment

Hyperhidrosis is a condition that is not serious in itself, but can pose a problem for the psychology of the patient. Sometimes this excessive sweating is an indication of a condition that needs to be treated.
Hyperhidrosis: Symptoms, Causes and Treatment
Samuel Antonio Sánchez Amador

Written and verified by el biólogo Samuel Antonio Sánchez Amador.

Last update: 12 June, 2021

Hyperhidrosis is a disease characterized by excessive secretion of sweat at one or more levels of the body. It’s produced by an excessive stimulation of cholinergic receptors in the eccrine glands, that is, a type of glandular body sweat that is found in almost all areas of the skin.

This pathology is produced by an excretion of sweat beyond the homeostatic mechanisms of internal temperature regulation. The highest concentration of eccrine glands is located in the armpits, palms of the feet, palms of the hands and face, and so it’s in these areas where the effects of hyperhidrosis are most noticeable.

It is estimated that in countries like the US the prevalence of this condition is close to 3% of the general population. Although it doesn’t have serious effects on the patient’s health, it can affect their socialization and mental health. If you want to know more about hyperhidrosis, including its causes and treatments, we encourage you to keep reading.

The importance of sweat for the body

Sweat is a liquid excreted by the sweat glands with an essential function in the thermoregulation of human beings. When body temperature rises beyond what is physiologically acceptable (due to emotions, environment, or exercise), this fluid is excreted to the outside to increase the rate of surface evaporation.

Sweat permeates the skin surface and evaporation occurs, resulting in heat dissipation. According to the Journal of the Faculty of Health Sciences, this is a critical thermoregulation mechanism when the temperature of the environment exceeds that of the organism. Through evaporation of sweat, up to 27% of body heat is lost.

This liquid is made up of water with small amounts of minerals, such as sodium, calcium, potassium, and some waste substances, such as urea. This entire process is regulated by the sympathetic nervous system, one of the divisions of the autonomic nervous system that is responsible for various involuntary actions.

To evaporate, sweat needs heat. This heat is collected from the body’s surface, which results in a decrease in the body’s general temperature.

Control of sweating

Control of sweating occurs in the preoptic area and the anterior nucleus of the hypothalamus. Here, specialized neurons are located that perceive changes in internal temperature or, failing that, changes in the cerebral cortex. The sweat glands are innervated by postganglionic sympathetic fibers, activated by the neurotransmitter acetylcholine.

In summary, these cholinergic fibers activate the eccrine glands, depending on changes in internal temperature, as indicated in the Journal of Plastic Surgery. In a normal situation, this isn’t a problem, as sweat appears in times of emotional stress, during exercise, or when it’s very hot.

What is hyperhidrosis and what causes it?

This extensive introduction was necessary, because, in order to understand hyperhidrosis, one must understand the general mechanism of sweat formation. As we have said, this condition is defined as a pathological condition in which the patient produces more sweat than they should, in situations that don’t respond to the regulation of normal body temperature.

The regions most affected by this condition are those that coincide with a higher concentration of sweat glands, both eccrine and apocrine. These are the palms of the hands, the palms of the feet, the armpits, and the face. Axillary hyperhidrosis is the most common of all (1.4% of the entire US population), followed by the palm (0.5%).

However, it should be noted that the apocrine glands haven’t been shown to play a relevant role in the development of hyperhidrosis. Today, it’s believed to be hyperstimulation in the cholinergic circuit described above, leading to overproduction of sweat by the eccrine glands.

On the other hand, the medical journal Deutsches Ärzteblatt International emphasizes that there are two main types of hyperhidrosis. We’ll discuss them below.

1. Primary hyperhidrosis

Primary hyperhidrosis is the one that doesn’t have a specific cause, that is, it has not arisen as a result of another condition, or previous treatment in the patient. The etiology of this condition is unknown, but it is believed that genetics could play an important role in hyperstimulating cholinergic fibers in the nervous system.

For example, the Perspirex portal shows us that, according to certain studies, up to 65% of patients with hyperhidrosis have some close relative who also has it. Although the causal genes of the disease haven’t been sequenced, the genetic correlation seems clear, as it’s believed that the probabilities of their inheritance are 25%.

2. Secondary hyperhidrosis

This variant of the pathology is much easier to address, as the underlying cause is known. Here are some possible causes of secondary hyperhidrosis.

  • Infections: In infectious cases, fever is typical, as the body is trying to kill the pathogen that multiplies inside. The hypothalamus detects this increase in body temperature and acts accordingly, promoting sweating. Therefore, it is normal for us to sweat when we have a fever.
  • Neurological disorders: Parkinsonism-type conditions can also cause excessive sweating. When the muscles are stiff in this condition, hyperhidrosis occurs, although the link between the two events isn’t fully understood.
  • Cancers: Night sweats are a typical symptom of patients with malignant neoplasms.
  • Medication: Many medications cause hyperhidrosis, such as dopamine agonists, SSRI-type antidepressants, antipsychotics, and more.

In summary, almost any pathology of a febrile nature can cause transient hyperhidrosis. Treatment of this variant depends on the underlying cause in its entirety, so we won’t dwell on it further in future sections.


Patients with primary hyperhidrosis report unwarranted excessive sweating. This sweating can occur in some areas more than others and the intensity of the clinical event can vary. To bridge these disparities, the International Hyperhidrosis Society has devised a subjective scale for patients with hyperhidrosis.

From 1 to 4, symptoms can be reported as follows, always from the patient’s point of view:

  1. My sweat is never noticeable, and it doesn’t interfere with my daily activities.
  2. Sweating is tolerable, but it sometimes interferes with my daily activities.
  3. My sweat is very intolerable and frequently interferes with my daily activities.
  4. My sweating is unbearable and always interferes with my daily activities.

It is estimated that 3% of the population suffers from primary hyperhidrosis and 51% of patients suffer from focal sweat secretion in the armpits. In addition, 30 to 65% of them mention that some other member of the family has suffered, or currently suffers, from the same condition as them.

Excess sweat production manifests itself visually, but it can also have certain effects on almost permanently damp areas. Some of them are the following:

  • Itching and inflammation, the product of an irritation caused by the sweat.
  • An unpleasant odor, which happens when commensal bacteria from the skin and waste products mix with the sweat.
  • A visible waste product of the combination of sweat, dead skin, bacteria, and chemicals (deodorants, perfumes, etc.)
  • Changes in the skin areas exposed to permanent discharge, such as wrinkles or discolorations.
  • Maceration (disintegration of the most superficial layer of the skin), generally on the soles of the feet. This is the result of excessive exposure to moisture caused by sweat, as shoes are a fairly tight environment.


The diagnosis of hyperhidrosis depends a lot on the age and health condition of the patient. If they are young, in almost all cases it’s assumed that the hyperhidrosis is primary, since there are usually no chronic conditions during the first twenty years of age. However, an underlying cause, which can be serious, is suspected in the aging population.

For example, if hyperhidrosis begins after a stroke or if the patient has been diagnosed with diabetes or hyperthyroidism, then extra tests are necessary. For hyperhidrosis to be considered primary, it must meet the following requirements:

  1. Excessive sweating is present for at least 6 months.
  2. Sweat production is greatest on the palms of the hands, palms of the feet, face, and armpits. In general, the site of focal hyperhidrosis is the armpits.
  3. This sweat production is bilateral and symmetrical.
  4. The production of sweat decreases a lot or stops altogether during the night.
  5. Excessive sweating episodes last at least 7 days, before reducing in severity.
  6. The patient is 25 years old or younger.
  7. There is a family history of hyperhidrosis.
  8. Sweating prevents the patient from leading a normal life.

This isn’t to say that an older person cannot suffer from primary hyperhidrosis. However, this is much less common, as the disease usually manifests early. If it appears suddenly, there’s likely to be an underlying cause of a pathological nature.

Treatment of hyperhidrosis

Treatment of hyperhidrosis has become easier in recent years, as science has provided solutions apart from surgical intervention. However, it should be noted that not all approaches work the same, and others only do so for a limited time. Here are the most common solutions.

Topical treatment

The first line of treatment consists of the administration of aluminum chloride 15-20% topically. This ointment mechanically clogs the pores that the eccrine glands flow into, which can reduce the rate of sweat excreted. This could also promote atrophy of the secretory glands, something that also helps with symptoms.

In more serious cases, topical ointments with other slightly more powerful chemical compounds can be used.

Systemic treatment

As you can guess, systemic treatment consists of the administration of anticholinergic drugs. As indicated by the StatPearls portal, these drugs block acetylcholine receptors on the nerve pathways involved. One of the most common drugs on this front is oxybutynin (Ditropan), 5 to 10 mg daily.

Despite their relative usefulness, anticholinergic drugs have sometimes been shown to do more harm than good in the doses necessary to stop hyperhidrosis. Dysfunctions of intestinal motility, urinary incontinence, mydriasis and other pathologies are side effects of these drugs.


Sympathectomy is the last option for treating hyperhidrosis. In this treatment, the ganglia responsible for transmitting the sweating signal to the different tissues are extracted. In facial sweat, T1, T2 and T3 are extracted for excess sweating in the palms of the hands and feet and T4 for axillary sweating.

The procedure can be performed by thoracoscopy, a minimally invasive surgical technique, with which the thoracic cavity is accessed easily and without leaving a scar. However, it’s common for postoperative complications to arise, such as another area of the body beginning to sweat excessively (compensatory sweating).

A condition that is difficult to solve

As you may have seen, hyperhidrosis is a condition that doesn’t go away overnight, at least in the primary symptoms. If the cause of excessive sweating is a diagnosed disease, putting an end to it will be enough for the patient to regain physiological normality.

If, on the contrary, this sweating appears at a young age, and isn’t linked to an underlying condition, then it must be addressed in the long term, with patience and many types of treatments. If all else fails and the problem affects the psychology of the patient in a serious way, then a sympathectomy of the aforementioned nodes is used as a last resort.

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