DEAR DR. DONOHUE: I am a 52-year-old male who, for the past year, has had profuse sweating from the neck up. My pillow is drenched at night. I am told I will just have to live with it. Where does a person like me go for help? – N.

DEAR DR. DONOHUE: I am a salesman, and my palms sweat so much I cannot shake people’s hands. This is a source of great embarrassment. What can I do? – G.D.

ANSWER: Three percent of the adult population of the U.S. and Canada suffer from hyperhidrosis – excessive sweating. That’s a lot of people, and that’s a lot of disrupted lives. Ordinary sweating occurs when the sweating center of the brain detects a rise in body temperature. Sweating lowers the temperature. Excessive sweating comes from signals emanating from a different area of the brain and is not a response to elevated body temperature. It’s an inappropriate activation of sweat glands.

The first step is for a doctor to look for any illness that triggers sweating – infections like TB, spinal-cord disorders, some cancers, endocrine-gland problems and so on. Admittedly, such causes are rare, but a search should be made.

When no cause can be found, excessive sweating of the palms, soles and underarms often responds to a 20 percent solution of aluminum chloride that has to be applied exactly as directed. If it doesn’t work, then a battery-powered unit that delivers a low level of electric current to the sweaty areas can diminish sweat production.

Injections of botulinum toxin can sometimes curtail sweating. The oral medicine clonidine can provide an option for facial sweating. You don’t have to live with the problem.

The International Hyperhidrosis Society has an excellent Web site at www.sweathelp.org.

DEAR DR. DONOHUE: For the past six months, whenever I eat in restaurants, I develop a dry mouth that can last for hours. I believe it’s because they use sulfites to keep salads fresh. I thought they were outlawed years ago. Why is this allowed? – R.C.

ANSWER: Sulfites – sulfur dioxide, sodium sulfite, potassium bisulfite and sodium metabisulfite – inhibit the growth of bacteria and are used in many foods and beverages: Wines, frozen vegetables, baked goods, fruit juices, sauces, vinegars and dried fruits. In 1986, the Food and Drug Administration prohibited their use on fruits and vegetables intended to be eaten raw. Restaurants used to spray them on foods featured in salad bars. They no longer do so.

For some sensitive people, sulfites cause hives or throat irritation. In a small number – particularly people with asthma – they can cause breathing problems. All foods with added sulfites are clearly marked.

I don’t believe your dry mouth is sulfite-related, but I don’t know what’s causing it. See your doctor to find out.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.