La transpiration

Dr Christophe HSU – dermatologist. Geneva, Switzerland

• Everybody sweats, women as much as men.
• Sweating is often perceived as unwanted and this alone explains why deodorants and other anti perspirants are so successful on the market.
• Some individuals sweat too much and this is called hyperhidrosis:

1. social discomfort is present
2. treatments include application of topicals containing aluminium chloride, Botulinum toxin injections, oral intake of anticholinergic substances, surgical sympathectomy.

• In some conditions, no sweating takes place because sweat glands are absent. This is the case of the group of diseases called ectodermal dysplasia. Individuals having this condition cannot regulate their body temperature efficiently and it can rapidly escalate to uncomfortable/dangerous temperatures.

Why sweat?

• Sweating is necessary to live. It is our cooling system preventing us from overheating.
• It enables us to maintain a constant body temperature (thermoregulation). This is needed to maintain intracellular enzymatic reactions which are essential to our functioning and life.
• The millions of sweat glands (especially eccrine here) and their excreting canals are disseminted throughout the skin of the body and enable evacuation of heat through liquid evacuation.
• Eccrine glands are located everywhere but are more numerous at these locations:

1. the soles of the feet
2. the palms of the hands
3. the forehead
4. the armpits

Why do some individuals sweat more than others?

• The quantitiy of sweat depends on the innervation of the sweat glands.
• These nerves are called cholinergic nerves and they are activated:

1. by heat
2. by emotional states
3. by stress

Why does sweat smell, sometimes awfully so (Bromhidrosis)?

• It is caused by the presence of sweat glands called apocrine glands:

1. Apocrine glands secrete a milky odorlous fluid containing proteins…
2. Once this fluid reaches the surface, bacteria acts upon it to create a unique smell which varies from one individual to the other.

• In most cases, this smell is undetectable or discrete, but in some individuals the odour is pungent and foul-smelling (Bromhidrosis or Bromidrosis). Causes of this lie:

1. in the secreted fluid
2. in the bacteria living on the surface of the skin

• Bromhidrosis (or Bromidrosis) can be controlled to some extent by taking antibiotics.

How does secretion by apocrine glands work?

• Secretion is dependent by regulation by the central nervous system through adrenalin circulating in the blood.
• It is important in the social interaction of animals, notably in sexual behaviour.
• Apocrine glands are located at the following locations:

1. the armpits
2. The areola
3. the anal canal

Contributors:

Dr Christophe HSU – dermatologist. Geneva, Switzerland

National Skin Centre. Singapore