DEAR DR. DONOHUE: I would like to know more about Sjogren’s syndrome. The doctor made the diagnosis after taking more than 25 blood tests. He is a rheumatologist. I am afraid I will get cancer because of it. The doctor has given me Plaquenil to take. – J.S.

ANSWER: Dry eyes and dry mouth are the principal signs of Sjogren’s (SHOW-grins) syndrome. The nose and throat can also be dry. Joints frequently hurt. Some patients come down with a dry cough. The kidneys can be affected.

All signs and symptoms stem from an attack by the immune system on the body’s own tissues and organs. Lymphocytes, one of the white blood cells, march into the saliva and tear glands on orders from the immune system. They upset the production of saliva and tears. The resulting dry eyes burn, redden and feel like sand is in them. A dry mouth makes swallowing and talking very difficult and promotes tooth decay. Joints frequently hurt. Sjogren’s is a disease not limited to the tear and saliva glands.

Your fear of cancer has a basis in fact, but the probability of developing it is not great. About 2.5 percent of Sjogren’s patients develop lymphoma, cancer of the lymph nodes. Your doctor will watch carefully for any inklings of that happening.

Some Sjogren’s patients have an underlying illness such as rheumatoid arthritis, lupus, scleroderma, biliary cirrhosis or chronic hepatitis. Doctors always look for these conditions in their Sjogren’s patients.

Artificial salivas, of which there are many, keep the mouth dry and preserve dental health. Chewing sugarless gum helps. Evoxac and Salagen (pilocarpine) can coax saliva from the salivary glands. Artificial tears keep the eyes moist. Restasis eyedrops often can spur the production of tears.

Get in touch with the Sjogren’s Syndrome Foundation at 800-475-6473 or on the Web at www.sjogrens.org. The foundation has a wealth of information on products useful for patients and keeps them up to date on the latest developments.

DEAR DR. DONOHUE: Why are there different terms in the Nutrition Facts on food labels? What are “g” and “mg”? I am confused by this. – J.S.

ANSWER: The “g” stands for grams. One gram is 1/30 of an ounce.

The “mg” is for milligrams. One milligram is 1/1,000 of a gram, a very small amount. Things found in trace quantities are given in milligrams, things like minerals.

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.