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Plantar Hyperhidrosis - Sweaty Feet

Plantar Hyperhidrosis - "Sweaty Feet"

Plantar Hyperhidrosis is characterized by intense sweating of the feet. It is a very common ailment affecting around 20% of the population, but only for a minority it reaches psychosocially debilitating levels. It may appear isolated (common) or associated with other types of hyperhidrosis, particularly abnormous hand sweat, a special disorder known as palmo-plantar hyperhidrosis


HYPERHIDROSIS = excessive secretion of sweat by the eccrine sweat glands.

Based on studies in which the sweating was measured accurately, a perspiration of about 100 mg per cm2 per minute is referred to as hyperhidrosis. In clinical practice, the severity of hyperhidrosis is considered not so much on the exact amount of sweat, but on subjective discomfort caused thereby or to the complaints.

The sweat glands respond to impulses of the sympathetic nervous system, a portion of the vegetative nervous system (autonomic nervous system). A defective or not optimally calibrated regulation of the secretion of sweat by the centers of the autonomic nervous system may lead to excessive perspiration, in some cases totally out of range. This dysfunction has a similarity with e.g. essential hypertension (high blood pressure): autonomous centers react in an exaggerated way to minimal input.

From a physiological point of view, the contribution of had and foot sweat for the regulation of body temperature is negligible. A minimal moisture of the palms and soles is, however, useful to guarantee a certain level of friction for a good grip and to prevent slipping. It appears obvious that the opposite occurs if sweating is excessive.

The perspiration varies throughout the day, from a minimum transpiration during the night up to peak values, for example, in connection with physical activity, psychological or psycho-physical stress, exposure to heat, etc.

Another factor determining the level of humidity of the skin is the capacity to evaporate, markedly reduced in humid climatic environment or when wearing closed shoes; other factors are the type of material of the shoes, the absorption capacity of the socks, etc.

BROMHIDROSIS = sweat with unpleasant odor.

Bromhidrosis is often associated with hyperhidrosis, but excessive sweating is not necessarily causing bad smell. On the contrary, the sweat itself is an odorless liquid when expelled from eccrine sweat glands.

The odor is caused by organic substances, splitted by microorganisms which colonize the skin surface and the material of socks and shoes. The molecules produced by such biochemical processes, mostly derivates of fatty acids (e.g. butyric acid), are dissolved in sweat and emit the characteristic odor of sweaty feet when evaporating. The sweat itself contributes to the creation of an environment in which the microorganisms thrive and proliferate and represents the vehicle for malodorous substances. Moreover, even in absence of bacteria and fungi, an unpleasant odor may be emanated from the shoes when traces of organic substances contained in the leather are dissolved in the sweat.

Generally, however, it is the contamination with microorganisms in a humid microclimate which constitutes the ideal environment for developing so called foetor pedis.


In most cases, no reason for increased footsweat apart from genetical factors will be detected.

Symptoms and consequences

Athlete's foot

Excessive foot sweat leads to several problems:

  • macerated skin (increased vulnerability)
  • mycosis (growth of fungi)
  • early wear of shoes (often a pair of shoes is worn down after just a few weeks)
  • difficulties in wearing certain types of footwear (e.g. sandals)

In addition, psychosocial discomfort (professional life, social and even familiar relationships) is common when bromhidrosis is associated with hyperhidrosis.

Without doubt, plantar hyperhidrosis may have a negative impact on the quality of life of many individuals and may be really debilitating for some.


Often measures aimed at reducing the activity of the sweat glands are not sufficient, but have to be combined with disinfection of the skin and the footware if bromhidrosis is the main problem.

Treatment of plantar bromhidrosis

  • wash the feet with disinfecting soap (e.g. detergents used by the surgeon to wash his hands prior to surgery);
  • after rinsing, rub the feet with an alcoholic solution with high disinfecting potential, preferably containing rehumidifying components, like those used in surgery and available in pharmacies;
  • treat mycosis (fungal disease) if present (consult a dermatologist);
  • disinfect shoes and socks regularly with a proper disinfecting spray, change socks frequently;
  • treatment of hyperhidrosis (see below)

Treatment of plantar hyperhidrosis

Botulinum toxin is not recommended for the treatment of foot sweat. The treatment is painful even with appropriate anesthesia, the required amount of substance at least twice as for the armpits and therefore twice as expensive, the effect usually inadequate and short-lived. In fact, to get a decent effect the patient would have to avoid pressure on his soles for 2 days, in order to allow the substance to act as long as possible locally without being carried away by the blood while walking or standing.