America\'s Dermatologist

Sweating is simply your body’s way of regulating its temperature and keeping cool.

The process is necessary for your health. The product of sweating—perspiration—is a salty liquid produced in your sweat glands, which are located in the dermis, or middle layer, of your skin.

How much you sweat depends on the number of sweat glands in your body. Women tend to have more sweat glands than men, but men’s sweat glands tend to be more active. Sweat glands are most common on the palms of the hand, the soles of the feet, and in the two underarm areas.
 

What Triggers Sweating?

We sweat in a number of situations—for example, when we’re hot, or exercising, or anxious. Eating certain foods, especially alcohol or caffeine, can make us perspire more than usual. So can certain medications, including antibiotics, blood pressure medicines, and even some dietary supplements.

Sweating is, of course, a side effect of fever, and therefore a sign of an illness. But sweating in the absence of a fever can also be a sign of an underlying medical condition, including diabetes, thyroid disorders, liver disease, and rheumatoid arthritis.
 

When Is Sweating Considered Excessive?

Some people just sweat more easily than others. It’s in their genetic makeup. Sweating is also more common in individuals who are overweight or out of shape.

But about 3 percent of Americans have an excessive sweating condition known as hyperhidrosis. Scientists believe hyperhidrosis occurs when the nerves that send messages to the sweat glands to produce perspiration go into overdrive, overstimulating the glands—and creating excess sweat.

When excessive sweating is caused by a medical condition, it’s known as secondary general hyperhidrosis. This condition tends to produce sweat all over the body. In other cases, however, the sweating is more localized, affecting only the hands, feet, groin, or underarms. This is known as primary focal hyperhidrosis. Although often triggered by emotional stimili, the precise cause of localized hyperhidrosis is unclear. Genetics appears to be involved. Studies have shown, for example, that up to 50 percent of individuals with excessive hand sweating had a family history of the condition.
 

How Is Excessive Sweating Treated?

Surveys have also found that less than half of all people with hyperhidrosis seek medical care for the condition. That’s unfortunate, as there are several effective treatments.

• Antiperspirants. Special “clinical-strength” over-the-counter antiperspirants can help individuals with mild to moderate hyperhidrosis. When these products are applied, the perspiration on the skin dissolves the antiperspirant particles,
  which then plugs up the pores and hinders the release of more perspiration. Your dermatologist may also recommend a prescription antiperspirant that’s applied to the skin each night before bedtime. It’s then washed off in the morning.
• Oral medications. Different oral medications, including anticholinergics (used to treat ulcers, gastritis, asthma, and other diseases) and beta blockers (heart disease), are sometimes prescribed for hyperhidrosis because one of their side effects is reducing stimulation of the sweat glands. Long-term use for hyperhidrosis, however, is not usually recommended because of the drugs’ many other potential side effects.
• Botulinum toxin (Botox). Better known as a facial wrinkle-reducer, Botox received the U.S. Food and Drug Administration’s approval for the treatment of axillary (underarm) hyperhidrosis in 2004. It’s also often used to treat sweaty palms. The Botox is injected into the skin, where it temporarily blocks the nerve signals that stimulate sweat glands. Results last for up to 6 months, at which point the treatment can be repeated.
• Iontophoresis. During this procedure, which is mainly used to treat excessive sweating of the hands and feet, low-level electrical impulses are applied to the affected area while the hand or foot is under water. Scientists aren’t exactly
  sure how iontophoresis interrupts sweat production, but it has a high treatment success rate—about 80 percent, according to the American Academy of Dermatology. The procedure must be repeated 1 to 4 times a month. The device can be used at home.
• Surgery. In severe cases of hyperhidrosis, surgery may be used to remove either the sweat glands or the nerves that are over-stimulating the sweat glands. These procedures have shown to be most effective for palm and underarm hyperhidrosis, and less effective for excessive sweating of the feet. Hyperhidrosis surgery carries serious risks, however—including nerve damage to other areas of the body—and should therefore be undertaken only after other methods have failed and only under the care of a skilled and experienced surgeon.