Hyperhidrosis (Excessive Sweating) - Causes, Symptoms and Treatment

Hyperhidrosis is a state in which the body produces a volume of sweat disproportionate to the physiological needs for the regulation of body temperature, that is, the patient perspires excessively and without reason.

Hyperhidrosis is usually a primary condition, with no apparent cause. However, there are some diseases and some medications that can cause excessive sweating.


What is sweat?

Sweat is a substance composed of water (99%) and small amounts of mineral salts (1%), basically sodium chloride and urea. Other substances in the blood may be present in sweat, such as calcium, magnesium, potassium, zinc and iron. These, however, are usually in very low concentrations.

Contrary to popular belief, sweat is not a source of toxins and is not used to remove impurities from your body. Spending time in a sauna can be relaxing, but it will not make you eliminate anything in relevant quantities other than water and salt.

Sweat is produced by the sweat glands, which are glands that are located in the innermost layers of the skin (dermis), communicating with the most superficial layer (epidermis) through micro ducts that flow into pores in our skin, can be seen in the image on the left.

Sweat has the basic function of helping regulate our body temperature. The production of sweat by the sweat glands is controlled by the central nervous system, namely by the hypothalamus, where the thermosensitive neurons meet.

The nervous system can also stimulate sweating in times of emotional stress. Usually, sweating in these cases is restricted to certain areas of the body such as hands, feet, armpits and head.

What is hyperhidrosis?

As already mentioned in the opening of the text, hyperhidrosis is a state in which the body transpires more than would be necessary to cool the body. Any point on the body can be affected by hyperhidrosis, however, palms of the hands, soles of the feet, face and armpits are the most common sites. As a rule, hyperhidrosis is a focal sweating, affecting only one area of the body.

Currently, for the diagnosis of hyperhidrosis we use the following criteria:
  • 1. Excessive focal sweating with more than 6 months duration and no apparent cause.

Two more of the criteria listed below:
  • 2. Bilateral and symmetrical sweating (affects both hands, feet and/or underarms).
  • 3. Sweating that disrupts everyday activities.
  • 4. Excessive sweating occurring at least 1x per week.
  • 5. Beginning of the period before the age of 25.
  • 6. Family history of hyperhidrosis.
  • 7. Focal sweating during sleep.

About 2% of the population presents criteria for the diagnosis of hyperhidrosis. People of Asian origin, mainly Japanese, have a greater risk of presenting the disease. Focal hyperhidrosis is more common in adolescents and young adults; less than 5% of cases begin after puberty, which causes all adults with excessive sweating of recent onset to be investigated for metabolic diseases or use of medications.

Hyperhidrosis usually worsens in periods of heat or during emotional stress, but many of these patients perspire at all times, with no apparent triggering factor.

Although it is not a serious illness that brings about greater complications, hyperhidrosis can be uncomfortable and disrupt the social and professional life of patients. Excessive underarm sweating can stain clothes and be aesthetically undesirable, while sweating on the hands can wet papers, make instrument handling a difficult task and cause embarrassment when shaking hands with other people.

In addition to social embarrassment, hyperhidrosis favors the appearance of some other skin diseases such as eczema, warts, atopic dermatitis, fungal nail infections, chilblains, folliculitis and unpleasant odors.

Causes of hyperhidrosis

Primary hyperhidrosis, that is, hyperhidrosis with no apparent cause, is usually localized, affecting only the hands, feet or armpits. Eventually, excessive sweating on the face and skull may be part of the picture.

When hyperhidrosis is diffuse and/or begins after adulthood, it is necessary to think about secondary causes, among them we can mention:

Medications that can cause hyperhidrosis include:

In general, when hyperhidrosis is being caused by some disease, the patient already has signs and symptoms that help us to identify the underlying disease. If the patient presents with fever, weight loss, cough, skin lesions, etc., it is easy to suspect that the onset of hyperhidrosis is related to a systemic disease and is not a primary condition. A hyperhidrosis that only arises during sleep also suggests the presence of a secondary cause.

Treatment of hyperhidrosis

There are several treatment options for hyperhidrosis, from deodorants to surgeries. The intensity of the symptoms, the site that perspires in excess and the expectations of patients should be taken into account when deciding which treatment is best for each case.

1. Antiperspirants

Antiperspirant deodorants are marketed in pharmacies and supermarkets and usually come in roll-on, cream or aerosol presentations. They are products that contain metal salts, usually aluminum salts, that clog the pores of the sweat glands on the skin. These products only work in cases of mild hyperhidrosis.

If common antiperspirants fail, there are more potent solutions, such as aluminum chloride hexahydrate in concentrations ranging from 10 to 30%, which can be used on the hands, feet and underarms. The results usually appear within a week, but it is common for the treatment to be discontinued due to skin irritation.

2. Remedies

Anticholinergics are a group of drugs that act by inhibiting the neurotransmitters that stimulate sweat secretion by the sweat glands. It is currently a poorly used treatment because of the high rate of side effects and poor efficacy. Glycopyrrolate (60% efficacy) and oxybutynin (50% efficacy rate) are the most commonly used.

In patients with hyperhidrosis related to emotional stress, the use of propranolol or anxiolytics such as diazepam may relieve symptoms.

3. Iontophoresis

Iontophoresis is used to treat palmar hyperhidrosis (hands) and plantar hyperhidrosis (feet). The treatment consists of the temporary blockade of the sweat glands through a light electric discharge emitted inside a container of water. Treatments last about 30 minutes and are usually applied on alternate days, with a success rate above 85%. The results are temporary and the treatment needs to be repeated constantly.

The most common adverse effects are irritation and dry skin. The device can be purchased and, after proper training, the patient can use it at home.

4. Applying Botox

The botulinum toxin, marketed under the brand name Botox, when applied in the regions that transpire in excess, act by blocking the neurons that stimulate the operation of the sweat glands, causing a temporary reduction of sweat production in these places.

Botox can be applied to the hands, feet, armpits and face, with a high success rate, with effects lasting several weeks.

The disadvantages of Botox applications are needle bites and the need for a well trained doctor to avoid complications such as muscle weakness.

5. Microwave thermolysis

This treatment is done through a device that emits microwaves capable of destroying the sweat glands. The treatment is usually done with 2 or 3 sessions of 30 minutes, with intervals of 3 months. The success rate is 80 to 90%.

The most common side effect of thermolysis is a strange sensation on the skin at the application site, which can last up to about 1 month.

The main negative factor of thermolysis is its current high cost.

6. Surgery for hyperhidrosis

If all the treatments explained above fail, surgery becomes an option.

There are two types of surgeries used to treat hyperhidrosis. One is the curettage or liposuction of the axilla, which removes the sweat glands. The other option is endoscopic thoracic sympathectomy (ETS), which is a major surgery and involves the removal of nerves from the spinal cord at the level of the thorax, responsible for the innervation of the sweat glands of the armpits, hands and face.

ETS is the last option because it is a more complex and risky procedure, performed under general anesthesia. In this surgery, an endoscope is inserted into the chest through the armpit. One of the lungs is deflated so the endoscope can reach the spine more easily. The procedure is performed first on one side and then the other.

Although it is a procedure with high success rates, ETS has a common and inconvenient adverse effect: compensatory sweating. This side effect consists of an intense and excessive sweat that occurs in other areas of the body, mainly in the back, abdomen and legs. It is an important side effect, which brings great dissatisfaction because the sweat can be as intense or even worse than the original sweating that led to surgery. For this reason, endoscopic thoracic sympathectomy is rarely indicated.

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