DEAR DR. DONOHUE: My dad is 84 and in good health except for diabetes, which he controls with pills and diet. He has a spreading red rash on his left leg, just above the ankle. I took him to a doctor, and the doctor told us it was cellulitis. He has my dad on antibiotics. The doctor said if things don’t turn around within two days, he will have to hospitalize my dad.

What is cellulitis, and how dangerous is it? – W.C.

ANSWER: Cellulitis is an infection of skin cells (hence “cellulitis”) and the tissues and fat beneath the skin. It can happen at any age, but more often it’s encountered in older people. People who have had a leg vein removed for cardiac bypass surgery and people who have had lymph nodes taken during cancer surgery are more susceptible to it. Your dad’s diabetes makes him vulnerable to all infections, including cellulitis.

Staph or Strep germs are responsible for most cases. These germs gain access into the skin through a scratch or cut, either of which can be so small that it goes unnoticed. Athlete’s foot provides another opportunity for bacterial invasion of the skin.

Infected skin turns red, hot and becomes swollen. It is quite painful. Spread is rapid. A person can almost watch the red margin advancing.

Cellulitis can be a dangerous infection if it goes untreated. A slowly progressing infection confined to a limited area can be treated at home with antibiotics. An infection that’s advancing quickly requires intravenous antibiotics in the hospital.

Most people weather a bout of cellulitis without any significant consequences except a terrible memory of the experience.

DEAR DR. DONOHUE: I have a bunch of brown, soft patches on my back and upper arms. They look a little like flat cauliflower. What are they? They don’t hurt or itch, but they look disgusting. Can they be removed? – D.R.

ANSWER: You must realize that a diagnosis by letter is, at best, a wild guess. I believe you’re talking about seborrheic keratoses. They aren’t cancer, and they don’t become cancer. They appear mostly in people over 50. Their diameter varies from small to greater than an inch. It looks like someone has pasted them on the skin. Their surface is rough and fissured – in a word, warty. Most often, they’re uniformly brown and rarely cause any symptoms.

It’s not safe to the play odds when it comes to brown or dark-colored skin patches. You need a professional eye to determine the exact nature of such things. You don’t describe a melanoma, the most serious kind of skin cancer, but you don’t want to take any chances by guessing.

Seborrheic keratoses can be removed easily. They can be frozen off; they can be scraped off; and sometimes they succumb to the application of cortisone ointments or creams.

DEAR DR. DONOHUE: My mother and her two sisters gained a tremendous amount of weight after menopause. I am nearing that age, and I dread the same fate. Is this a genetic trait, and am I doomed to the same thing? – N.D.

ANSWER: Many women gain 5 to 10 pounds after menopause unless they are extremely careful in watching their calorie intake and unless they faithfully exercise. Why this happens isn’t clear. It seems that everything that happens to a woman after menopause is explained by the diminished production of estrogen, but there’s no proof that weight gain can be linked to a dropoff in estrogen. It probably has more to do with a cutback in physical activity. Most everything has roots in genetics, but this is a trait that can be altered by exercise and diet.

DEAR DR. DONOHUE: I am an 83-year-old man who has a diagnosis of prostate cancer. My doctor has given me a number of choices for treatment. I have chosen hormone shots. Would I be better off if I had the gland removed? I have no pain whatsoever. – E.F.

ANSWER: A number of factors have to be considered to arrive at the best treatment for prostate cancer. The stage of the cancer is an important determinant. Stage is determined by the depth to which the cancer has invaded the gland and whether it has spread to tissues surrounding the gland or to distant sites. The Gleason score is another consideration. It’s a measure of the cancer’s aggressiveness. A high Gleason number – 10 is the highest – indicates a cancer that multiplies and spreads quickly. A low number – 2 is the lowest – is given to a cancer that grows slowly. The degree of PSA elevation – the blood test for prostate cancer – is factored into the decision, as are a man’s age, his general health, his expected longevity and the potential complications of treatment.

If the cancer is confined to the gland, then surgery or radiation is the usual treatment. If the cancer is far advanced and has spread out of the gland, eliminating testosterone production is often the choice. Testosterone spurs the growth of prostate cancer. Testosterone production can be stopped by removing the testes or giving hormone shots.

Another alternative is watchful waiting. Many older men with a slowly growing tumor do not die from prostate cancer but from some other problem, like heart disease. Therefore, if a man’s life expectancy is less than 10 years and his tumor doesn’t have the characteristics of rapid growth, that man can choose to have his doctor follow the course of his tumor and withhold treatment until there are signs that the tumor is enlarging. The choice of treatment is your call. However, your doctor has to provide you with relevant information so you can make an informed choice.

The prostate-gland booklet describes enlargement and cancer of the gland. To obtain a copy, write to: Dr. Donohue – No. 1001, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.