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, the dermis. Sweat glands occur all over the body, but are most numerous on the forehead, the armpits, the palms and the soles of the feet.

Sweat is mainly water, but it also contains some salts

Its main function is to control body temperature

As the water in the sweat evaporates, the surface of the skin cools. An additional function of sweat is to help with gripping, by slightly moistening the palms. Normal, healthy sweating is caused by: fever associated with illness.

Excessive sweating is known as hyperhidrosis

Idiopathic hyperhidrosis is the most common form

It is called idiopathic because no cause can be found for it. It can develop during childhood or later in life and can affect any part of the body, but the palms and soles or the armpits are the most commonly affected areas. The excessive sweating may occur even during cool weather, but it is worse during warm weather and when a person is under emotional stress.

Some known causes include: In most cases, no investigations are required to diagnose hyperhidrosis.

Treatment for excessive sweating depends on the cause

  • topical applications (applying prescribed substances to the skin) such as
  • anticholinergic’ medications
  • which may be available as a cream
  • spray powder stick
  • roll-on wipe paint medical management
  • for example
  • iontophoresis – the activity of sweat glands is temporarily reduced by passing a low-level electric current through the skin botox injections – to paralyse sweat glands

The effect from a single injection lasts six to nine months non-invasive microwave treatment (the MiraDry® system approved by FDA in 2011) – for excessive sweating of armpits surgery to the nerves that control sweat glands – may be considered in severe cases where all other treatments have been unsuccessful.

Some strategies for managing hyperhidrosis at home include: Wear loose clothing.

Use antiperspirants that contain aluminium chloride and are designed for hyperhidrosis – follow the instructions carefully. While advertised mainly for use in the armpits, these agents can also be used on the palms, soles and forehead or wherever the hyperhidrosis occurs. Reduced sweating is called hypohidrosis if there is partial loss of sweating, or anhidrosis if there is complete lack of sweating.

This can occur for a number of reasons, which include:

  • prolonged excessive heat or exercise during hot weather. Lack of sweating may create problems of temperature control
  • lead to steep rises in body temperature during hot weather. Occasionally
  • this can be life threatening. can occur in hot weather when not enough sweat is produced to keep the body cool

Symptoms can include: vomiting

Excessive loss of body salts and water can lead to a life-threatening complication known as heat exhaustion. can be managed, and heat exhaustion prevented, by seeking a cool, shaded place, drinking plenty of fluids and sponging the body with water, if necessary. Sweat is produced by glands in the deeper layer of the skin Normal sweating hot temperatures, such as in summer physical exercise emotional stress eating hot or spicy foods Increased sweating (hyperhidrosis) obesity hormonal changes associated with menopause (hot flushes) illnesses associated with fever , such as infection or malaria an overactive thyroid gland (hyperthyroidism) diabetes certain medications Treatment for excessive sweating weight reduction – if the person is overweight antiperspirants with 10–25% aluminium salts oral ‘anticholinergic’ medications can be prescribed to block the activation of sweat glands hormone replacement therapy can be prescribed to reduce the hot flushes of menopause Self-help strategies for hyperhidrosis Reduced sweating (hypohidrosis) some skin disorders burns to skin that damage the sweat glands underactive thyroid (hypothyroidism) dehydration Heat stroke and heat exhaustion Heat stroke (or sun stroke) muscle cramps headache nausea Heat stroke Where to get help Your GP (doctor) A dermatologist.

Key Points

  • Sweat is mainly water, but it also contains some salts
  • Its main function is to control body temperature
  • Normal, healthy sweating is caused by: fever associated with illness
  • Idiopathic hyperhidrosis is the most common form
  • called idiopathic because no cause can be found for it