DEAR DR. DONOHUE. I had a colonoscopy, and the doctor didn’t find any cancer or any polyps. He did find diverticulosis. He seemed unconcerned by it. Should I be? – L.M.

ANSWER: A diverticulum is a pea- to grape-sized protrusion of the colon lining through the colon’s muscular wall. It’s a very common condition in Western countries. In those countries about 5 percent of people in their 40s have diverticula on their colons – diverticulosis – and by age 80 more than 50 percent have it.

It’s believed to come from our highly refined diet. In preparing grains, we discard the outer cover of grain – the bran. Bran contains fiber, and fiber is nature’s laxative. Without enough fiber, undigested food dries, and the colon has to generate great force to move it along. That force, in turn, pushes the colon lining through the colon wall to form diverticula. Most of the time, having diverticula poses no great problem.

However, 10 percent to 25 percent of those with diverticulosis develop diverticulitis – inflammation of a diverticulum. That happens when the opening of the diverticulum becomes blocked with rock-hard stool. Blockage leads to inflammation. The inflamed diverticulum can burst and then seal off. The process is quite painful.

Prevention of diverticulosis and its progression hinges on adding fiber to the diet – plenty of fruits, vegetables and whole grains.

Treatment of diverticulitis is entirely different. When it flares up, people are put on a liquid diet and oral antibiotics. If the process is quite extensive and painful, hospitalization is necessary to provide nutrition through intravenous feeding and to administer antibiotics by vein. In the most serious of all attacks, it might be necessary to remove the section of colon that is studded with inflamed diverticula.

The diverticulosis booklet presents the facts on this common condition. Readers can order a copy by writing: Dr. Donohue – No. 502, 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.

DEAR DR. DONOHUE: My problem occurs when I eat. It doesn’t happen all the time, but it is becoming more frequent. Food seems to get stuck just below my breast. It is very painful. I sit really still, and eventually it goes down. But before the episode ends, I vomit what I ate, and then I continue to vomit what appears to be stomach juices. Then I am fine. Can you tell me if this is something serious? – S.R.

ANSWER: Food sticking in the esophagus – the tube running from the throat to the stomach – is something that cannot be ignored, and the fact that it is occurring with greater frequency makes it deserve immediate attention.

It’s not my intention to scare you, but you should understand some of the problems this could represent. The most pressing is, of course, a tumor of the esophagus. Or it could happen from scars that formed in the esophagus from such things as acid reflux. Spasms of the esophagus’s muscular wall are another cause for food to stick in it.

Some illnesses produce this symptom. Scleroderma is an example. It’s a condition where there is an overproduction of the body’s supporting protein, collagen. It can harden the skin and internal organs. When it affects the esophagus, swallowing food becomes most difficult.

You have to get to the bottom of this quickly. X-rays of the esophagus after swallowing barium can often delineate the cause. Or a scope examination of the esophagus gives the doctor direct visualization of what’s going on in that structure.

DEAR DR. DONOHUE: I am 66, with dark-colored skin on my legs and ankles. I’ve been told this could be poor circulation. Could it? – K.T.

ANSWER: It could be stasis dermatitis. Distended leg veins leak blood into the surrounding skin. The red blood cells disintegrate and leave deposits of iron in the skin, which discolors it. Your doctor can advise you if this is what’s happening.

DEAR DR. DONOHUE: I started using a hot tub a few months ago. A friend tells me you can get herpes if you sit where someone who has the virus sits. He also says sitting in a tub is a good way to get hepatitis. I am worried sick. Are these tubs safe? – A.M.

ANSWER: Neither herpes nor hepatitis has ever been shown to be transmitted in hot tubs.

DEAR DR. DONOHUE: My dog died, and the vet said it was either an autoimmune something (my mind was spinning at the time, and I didn’t catch all the words) or cancer.

Do dogs get AIDS, and can people get it from them? I connect “autoimmune” with AIDS. – J.F.

ANSWER: Acquired immunodeficiency syndrome – AIDS – is caused by the human immunodeficiency virus, HIV. Please note the “human” in the virus’s name. Dogs don’t get AIDS. Your dog did not die of it.

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.