DEAR DR. DONOHUE: I’m beginning to get little knobs on my finger joints. I believe this is arthritis, and I have seen it in the advanced stages. What can I do to prevent it from getting worse? – Anon.

ANSWER: The knobs on the finger joints below the fingernail are Heberden’s nodes, named after an English doctor who died at the start of the 19th century. Knobs on the middle finger joints are Bouchard’s nodes, named after a French doctor who died in the early years of the 20th century. Both of these knobs are signs of osteoarthritis – the common kind of arthritis, the kind that most seniors have at least a touch of. They’re similar to bone spurs seen on backbones and other bones, another consequence of osteoarthritis.

Osteoarthritis comes from fraying of the cushioning cartilage inside joints. How extensive or how incapacitating it will be is unpredictable. Most people manage to get along in spite of it. However, it can be a great burden to others.

There is no preventive medicine to stop osteoarthritis in its tracks. It has a predilection for the fingers, hips, knees and spine. Should it strike larger joints like hips, knees and backbones, muscle strengthening will serve you well. Strong muscles protect joints. The exercise should not be so vigorous that it causes pain, but it should be vigorous enough to encourage strength building. Being overweight increases the stress on knees and hips, so you should strive to stay on the lean side.

Many people swear to the effectiveness of chondroitin and glucosamine, both of which are available without a prescription, and often they come in combination. Not a lot of evidence exists to endorse them wholeheartedly, but if you want to give them a try, they won’t hurt you.

FOR READERS: Thyroid gland problems are common. The booklet on this gland explains both an underactive and overactive gland. Readers can order a copy by writing: Dr. Donohue – No. 401, Box 536475 Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: My mother is in an assisted-living home. She came down with a rash over 90 percent of her body. The itch nearly drove her out of her mind. A doctor took a look at her and said she had scabies. My mother is beside herself with shame. The Internet says scabies is contracted through sexual activities. Mom thinks it is a dirty disease, and she cries all the time. Can you shed some light on this? – E.M.

ANSWER: Tell your mother that scabies affects people of all races, of all classes, of all social strata and of all ages. It’s acquired through close personal contact. People in the 18-to-30 age group often get it through sexual contact, but others get it from ordinary personal contact with an infected person. Children come down with it. If she truly has scabies, someone in the home gave it to her – another patient, or one of the staff. The contact occurred three to four weeks before the itch started.

Diagnosis of scabies takes more than a cursory look at the skin. Scrapings of the skin examined with a magnifying glass or a microscope show the mite, its eggs or its waste material. The female scabies mite burrows into the skin to make a tunnel for deposit of her eggs.

The tunnels look like fine, black lines about the size of black threads. The affected skin most often is the areas between the fingers, extending onto the backs of the hands, the wrists, the lower abdomen, the pelvic area and the ankles.

A whole-body rash is not usual. I have doubts about the diagnosis. Scabies is treatable with permethrin (Elimite) cream or lotion, or with the oral medicine ivermectin. Antihistamines can control the fierce itching.

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.