Sweating

Definition

Excessive sweating is a symptom that is characteristic of many conditions, both physiological and psychological.  Sweating is also a normal response to excess heat generation in the body (during physical activity, for example), since it is a means of losing heat.  The degree to which sweat drips off the skin (noticeable perspiration) is dependent largely on the environmental conditions, since high humidity prevents evaporation and thus increases dripping of sweat.  This can often explain excessive sweating, not because sweat production is higher, but because the dripping of the sweat that is produced is more obvious.

However, there are conditions under which sweating is increased, and these will be discussed below.

Other names

Perspiration, excessive perspiration/sweating

Possible causes

Sweating is a normal physiological response to heat generation, since it serves to cool the body when it evaporates. Therefore, excessive sweat must first be assessed in the context of the person’s physical activity and the environment.  Physical activity, high temperatures and high humidity are all expected to increase sweating, and so sweating would not be a symptom of any condition under these circumstances.

Assuming that the sweating is not a function of either physical activity nor the  environment, hyperhidrosis can be identified as a possible condition of which sweating is the key symptom, which can be caused by numerous physiological or psychological factors.

Two types of hyperhidrosis are identified.  In primary hyperhydrosis, the hands, feet and armpits are usually affected. This is likely genetic in origin, and is attributed to an excessively high concentration of sweat glands. The nerves that control the sweat glands could cause them to be overactive.

Secondary hyperhidrosis is a condition where excessive sweating occurs as a result of some other medical condition. These conditions include:
Hyperthyroidism, cancer, certain medications, glucose control disorders, menopause, and psychiatric problems such anxiety disorders and excessive stress.

Homecare/self-treatment

Antiperspirants can control sweating, with stronger forms often prescribed for patients with particularly severe sweating. These may however irritate the skin, leading to consideration of other options, through consultation with a doctor.

When to see a doctor

While the symptom (sweating) is by itself not harmful, the conditions causing excessive sweating can have serious consequences.  Therefore, if sweating is accompanied by sudden and unexplained weight loss, chest pain, fever and rapid heartbeat or shortness of breath, a doctor should be consulted immediately.  In addition, excessive sweating may cause embarrassment and self-esteem issues, and so if the patient feels that excessive sweating is affecting their social interactions, a doctor should be consulted for treatment options.

What to expect at the doctor

Doctors will ask for a detailed medical history, in order to establish symptoms associated with sweating. They will also try and determine location, time patterns, and factors causing sweating.  Specific tests that are done include an starch-iodine test, where an iodine solution followed by starch powder is applied to the skin in order to detect sweat gland activity.  Another test, the paper test, is used to determine sweat volume.  However, the patient history and descriptions of the sweating and associated symptoms are usually sufficient to prescribe a course of treatment.

Treatment

In addition to the prescription of stronger anti-perspirants, doctors may also recommend:

• Medication – these drugs block the nerves that usually stimulate sweat glands, and are known as anti-cholinergic drugs.
• Iontophoresis – this treatment method involves passing a small electric current through the body (via the feet and hands) for about 20 minutes to de-activate the sweat glands temporarily.  The treatment is aimed at deactivating the sweat gland (which usually takes about eight sessions - treatment is repeated approximately every 4 weeks, though may be more frequent depending on the case).
• Botox – this toxin (used also for plastic surgery purposes) is used as a treatment for underarm sweating, because it blocks the nerves stimulating sweating.  There are again side effects such as injection pain and flu-like symptoms
• Endoscopic thoracic sympathectomy – this treatment is used in severe cases, and involves surgery to destroy the nerves that are identified as causing the excessive sweating.  While minimally invasive, the surgery is really the final treatment option, and is considered only for serious cases.