Hyperhidrosis Center

Sweating it out; the problem of profuse perspiration - includes related article on deodorants
FDA Consumer, Dec, 1985 by Dixie Farley

In only 15 minutes, profuse perspiration drenches a woman's clothes. Sweat drips steadily onto machinery from the hands of a worker called "the ruster." Waterlogged socks steep a young man's feet until they're spongy, sore and foul-smelling.

Those people are fictitious. But their condition--persistent, excessive sweating--is very real. Medically speaking, it's known as hyperhidrosis.

That many people are at least "annoyed" by underarm perspiration is evidenced by the millions of dollars spent each year on antiperspirants. (See accompanying article.) Unfortunately, for those suffering from hyperhidrosis, perspiration is far more than just annoying. Their excessive sweating often causes severe embarrassment, restricted social activity and, as with "the ruster," problems in performing their jobs.

An understanding of sweating, excessive and otherwise, begins with a look at the glands that produce sweat. There are two types: apocrine and eccrine.

Apocrine sweat glands appear in the areas of the groin, anus and nipples as well as in the underarms, where they are largest and most active. They are poorly developed in childhood and enlarge considerably near puberty. Apocrine sweat normally is scanty and is produced intermittently at a slow rate. It is a sticky, milky substance composed of proteins, carbohydrates and lipids (a group of water-insoluble organic materials with a greasy feel). Sterile and odorless upon arrival at the skin surface, apocrine sweat acquires its unpleasant odor from bacterial decomposition of its constituents.

It is generally accepted that apocrine sweat glands serve no useful physiological purpose, their only apparent outstanding capability being to foster the development of an embarrassing smell. But body odor works functionally for animals, so perhaps there's more to be said about human body odor. Among animals, for instance, it's been shown that odor-bearing secretions are an important means of communication. There is a speculation that humans, too, might subconsciously send sexual signals through the odor of chemicals known as "pheromones." An FDA advisory panel evaluating nonprescription antiperspirants reported in 1978: "Axillary [underarm] sweating functions apart from the usual thermo-regulatory [heat-controlling] sweating system. It is stimulated by emotional signals, not just heat. It becomes active only after puberty. The combination of a potentially odorous substrate; a hospitable, warm, moist environment for the requisite bacterial growth; a large volume of evaporate vehicle for odor dissemination; and a wicklike tuft of hair all point to an efficient system for broadcasting chemical signals."

Pheromones haven't yet been detected in human sweat, so whether underarm perspiration plays a role as a sexual signal remains largely speculative. And in view of how much Americans spend on "sweatbusting," they evidently don't want Mother Nature's broadcast on the air anyway.

Unlike the seemingly useless apocrine sweat glands, eccrine sweat glands perform a vital function: They cool the body through evaporation of their secretion, which is mostly water. Eccrine sweat is clear and contains salt, potassium, urea, lactate, and traces of other compounds. Its composition varies with many factors, such as fluid intake, external temperature, and hormonal activity. And, although eccrine sweat contains such products as urea, the notion that sweat "purifies" the blood by excreting waste products in a manner similar to the kidneys is not scientifically supported. Like apocrine perspiration, eccrine sweat is sterile and generally ordorless. But when certain foods, such as garlic, are eaten, the sweat may take on their odor.

Roughly 3 million eccrine glands cover almost every area of the body, save the lips and some of the genitalia. On the underarms, soles and palms, they gather in crowds--as many as 3,000 per square inch on the palms. While eccrine glands normaly produce sweat in a daily amount ranging from negligible to about a quart, extreme circumstances can raise that amount to as much as 12 quarts in 24 hours. Most people have experienced excessive sweating from time to time as a result of heat, physical activity, or emotion. Such factors as race, age, sex, conditioning, and sensitivity to heat also can vary the amount a person sweats. Still, normal eccrine perspiration doesn't measure up to the great wetness of hyperhidrosis.

In "Diseases of the Apocrine and Eccrine Sweat Glands" in Dermatology, Dr. Harry J. Hurley lists more than 50 factors that cause, or are associated with, hyperhidrosis. As with normal perspiration, heat is a frequent cause of exaggerated sweating. That heat may be from sources outside the body, such as hot weather or a hot room. It may also be associated with factors within the body, such as malaria, diabetes mellitus, tumors, an overactive thyroids or pituitary gland, menopause, obesity, gout, and alcohol intoxication. Sweating in response to heat occurs primarily on the trunk and face, where sweat evaporates most readily in cooling the body.

Eating or drinking spicy foods and beverages also can bring on a hyperhidrotic cascade, on the face. Called gustatory hyperhidrosis, some cases are thought to reflect damage--as from a tumor, mumps or surgery--near the parotid salivary gland, with the result that impulses sent to sweat and salivary glands become mixed up. Thus, sweating rather than salivating occurs.

But the most common cause of persistent, troublesome hyperhidrosis is emotion. What is it that makes some people react so drenchingly to stressful situations that elicit only a mild reaction in others? No one seems to know for sure. Hurley writes that "a satisfactory explanation of the exaggerated sweating of emotional hyperhidrosis is still not available. A genetic factor ... is apparently operative and predisposes the affected individual in some as yet unknown way."

The onset of emotional hyperhidrosis is usually in childhood or around puberty. Patients describe constant, heavy sweating on their palms and soles (palmar-plantar type) or on their underarms (axillary type). The affected skin may be pink or bluish white and may become cracked and scaling in severe cases, especially on the soles because of the lack of air circulation. Some patients have both palmar-planter and axillary emotional hyperhidrosis, but one type usually predominates. According to Hurley, while both types have been seen in all races and both sexes, "women generally perspire less than men but tolerate it less."

In view of the great concentration of eccrine glands on the palms, it's no wonder that extreme palmar sweating can interfere with a career that often requires dry hands, as is the case for a jeweler, salesperson or industrial worker, to name a few. In hyperhidrosis, sweat constantly drips from the palms and fingertips.

For foot sweaters, close-fitting shoes can literally "stew" the soles in their own sweat, so it's important to get rid of as much moisture as possible. What's more, a bad odor may develop from bacterial decomposition of cellular debris caused by the scaling off of the outer layer of skin. Writing in the Journal of the American Podiatry Association (September 1983), William M. Jenkin, D.P.M., and Charles W. Craft offer these steps to help people dry out their over-perspiring soles:

Wear shoes made only of leather or fabric, which "breathe."

Choose footwear, such as sandals, that allows air circulation. Change shoes daily so they can dry thoroughly before they're worn again.

Wear cotton socks. Change socks at midday (and shoes, too, if necessary).

Use powder (no cornstarch) to absorb moisture.

In underarm emotional hyperhidrosis, sweating can be so profuse that a persons's shirt and suitcoat become soaked within 15 to 30 minutes. Patients with underarm hyperhidrosis seldom have underarm odor, most likely because their profuse eccrine sweat washes away their apocrine sweat.

Emotional hyperhidrosis sometimes improves spontaneously around age 25. For persistent cases, however, dermatologists may prescribe topical agents--the first choice being a solution of aluminum chloride in absolute ethyl alcohol. To help prevent irritation and improve penetration of the active ingredient, the product should be applied to thoroughly dry skin, preferably at bedtime. After two or more applications, the heavy sweating may stop and, from then on, the product is usually applied once or twice a week, or as needed.

When all else fails in treating underarm hyperhidrosis, surfical removal of the sweat glands from the armpits has often proven successful. Several methods of reducing the mass of underarm sweat-gland tissue have been described; they vary from selecting only the overactive glands to removing the skin layer containing sweat glands from the entire underarm area.

Scarring, of course, depends on which procedure is used, but it will not usually be visible when the arm is at the side. Whether decreased underarm sweating is worth the scars and, possibly, increased sweating on other areas of the body is an individual decision. Dr. C Carnot Evans, a dermatologist with FDA's Center for Drugs and Biologics, adds, "Even if increased sweating occurs elsewhere to compensate for the absent armpit, patients nearly always prefer to deal with sweat in places other than the underarms."

Another surgical procedure that is sometimes used is a "sympathectomy," in which the nerves that connect the sweat glands to the nervous system are severed. But according to Dr. R. Kenneth Landow, writing in the Handbook of Dermatologic Treatment (1983), while results may initially be good, "a fair number of patients develop the recurrence of symptoms within 5 years." Also, it's possible that tissue damage may occur and cause a condition known as "Horner's syndrome," in which nerve paralysis results in drooping of the eyelids and other effects. Patients for whom any surgery has been recommended should thoroughly discuss the procedure with their physicians so that they clearly understand the risks and benefits.

Some physicians treat hyperhidrotic patients with prescription drugs known as anticholinergics. Although the drugs are marketed for uses other than hyperhidrosis therapy--reducing acid secretions in patients with peptic ulcers, for instance--Landow and other physicians have reported that hyperhidrotic patients also may benefit from short-term use of the drugs. Further, side effects such as dry mouth, drowsiness, and constipation caused by the drugs may be as undesirable as the sweating. And, according to Hurley, "Systemic anticholinergic drugs, even in doses productive of unpleasant side effects, rarely satisfactorily suppress the sweating." FDA's Evans agrees that the reduced level of sweating may still be so great as to be uncomfortable. Topically applied anticholinergics are reported to be effective with minimal side effects. Hyperhidrosis therapy is not an FDA-Approved indication for any form of an anticholinergic drug.

A device that uses iontophoresis, in which ions (charged atoms) are electrically driven into the skin, has been said to inhibit sweat on the palms, soles and underarms. But FDA's Center for Devices and Radiological Health, which regulates iontophoresis devices, has determined that existing information is insufficient to establish the device's safety and effectiveness for use in inhibiting sweat. The device is available only by prescription.

Other treatments for emotional hyperhidrosis with reported varying degrees of success include psychotherapeutic techniques such as biofeedback. (In biofeedback, the patient consciously tries to exert control over a bodily function, such as sweating, by using an instrument that monitors and records changes in that function.)

The treatments for hyperhidrosis may seem less than satisfactory, but perhaps a better, drier bottom line will yet be written. Meanwhile, the best source of advice for those seeking help is their physicians.

COPYRIGHT 1985 U.S. Government Printing Office
COPYRIGHT 2004 Gale Group

Hyperhidrosis or Excessive Sweating

What is hyperhidrosis?
Where does hyperhidrosis occur?
What are the symptoms of hyperhidrosis?
What are the alternative treatments for hyperhidrosis?
Is there a surgical treatment for hyperhidrosis?