DEAR DR. ROACH: My mom is 77 years old. Three years ago, she developed a blood clot in her leg and needed surgery. This year, she developed an ulcer in that leg. How do you develop ulcers on your leg or other part of your body? I thought ulcers were only in the stomach. Is it caused by an infection? — R.G.

ANSWER: “Ulcer” is just a term for a shallow erosion, usually in the outermost layer of an organ. Cells must be damaged for an erosion to occur. In the stomach, it is infection by a species of bacteria, Helicobacter pylori, that is responsible for most ulcers, but aspirin or other anti-inflammatory medications can cause them as well.

An ulcer in the leg usually comes from poor circulation. Arteries bring oxygen-carrying blood to the muscles and other cells, and veins take oxygen-depleted blood away. Damage to the arteries or veins can lead to ulcers. In your mother’s case, it is likely to be the veins, which were damaged as a result of the blood clot. Blood clots cause swelling of the skin and damage to the blood vessels, which can predispose the area to an ulcer with even minimal trauma. Infection isn’t needed to cause an ulcer, but it makes treating the ulcer much more difficult.

TO READERS: The booklet on colon cancer provides useful information on the causes and cures of this common malady. Readers can obtain a copy by writing: Dr. Roach — No. 505, 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. ROACH: I have roseola, and have been using metronidazole topical cream. Can you tell me anything about this rash? — B.B.

ANSWER: Roseola, sometimes called sixth disease, is a viral infection found most commonly in children between 6 months and 2 years old. It is caused by a herpes virus, is characterized by a high fever and distinctive rash and usually goes away without treatment, but the fevers can rise high enough to trigger seizures. That’s not what you have.

You have rosacea, a skin condition of the cheeks, nose or other parts of the face. Rosacea is red, bumpy and has small, swollen blood vessels called telangiectasias. It tends to get worse with consumption of hot liquids or alcohol, or exposure to sunlight. Metronidazole cream is effective for many people, but you’ll need to avoid triggers, since the condition tends to worsen over time.

DEAR DR. ROACH: I really like the very thorough answers in your columns! Would that all doctors could take the time to explain things as you do.

But I’d appreciate a clarification of a recent answer you gave. You said that, regarding washing hands to get rid of germs, the soap does not kill the germs — it is the rinsing away of the germs that does the trick.

So why then do we use soap? I’m quite confused about all this. — A.D.M.

ANSWER: Hand-washing, for 30 seconds under warm water and with soap, is enough to kill most germs. However, I was speaking about a particularly nasty germ, the spore of Clostridium dificile (“C. diff”), which is not killed by soap and water. It’s not killed by alcohol hand cleansers, either. The reason that hand-washing is important is that to avoid infecting ourselves and other people, we want to get rid of any infectious germs on our hands. Even though soap and water can’t kill the C. diff spores, it gets rid of them by washing them down the drain.

Alcohol hand cleansers, such as Purell, are a good choice to help reduce infection. However, in the case of known C. diff, hand-washing remains the better choice.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Health newsletters may be ordered from www.rbmamall.com.

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