DEAR DR. DONOHUE: I read your answer to a question on scleroderma. Your simplistic explanation of “hardening of the skin” is very misleading.

This is a disease that causes hardening of organs. Please inform your readers that this illness can affect internal organs. We who suffer from this disease only wish there was more awareness of how serious this condition is. – J.C.

ANSWER: The two Greek words “sclera” and “derma” do mean “hard skin.” A casual observer can notice the skin changes of people who have this illness. The face tightens and shines, and breaking into a smile is all but impossible. Finger and hand skin can become so taut that a person can lose the ability to grip a fork or a pencil.

You are so right. Scleroderma can involve internal organs. The same process going on in the skin can enmesh the lungs in strands of scar tissue so dense that the victim struggles for air. Scar tissue in the esophagus makes swallowing painful and troublesome. In the digestive tract it inhibits the absorption of nutrients. Joints all over the body might throb with pain. Kidney involvement is particularly treacherous. It leads to high blood pressure and kidney failure.

The last time I wrote about scleroderma, I wrote about morphea. It is a variant of the kind of scleroderma that attacks both skin and internal organs. Morphea remains localized to the skin.

You and other scleroderma patients can obtain the latest information on this illness and its treatment by contacting the Scleroderma Foundation. The foundation will keep you up-to-date on what scientists might have discovered about the nature of this illness and on what changes, if any, have taken place in treatment. You can reach the foundation at (800) 722-4673. Its Web site is www.scleroderma.org.

DEAR DR. DONOHUE: I drove myself for 50 miles to the hospital ER while choking all the way. I heard doctors say that I should be dead, for my lips had darkened and my fingernails turned blue. I believe this was caused by a change in my medicine. I was taking Zestril, but the pharmacy changed it to lisinopril. Will you explain the reason for this change and how it is allowed? My life is on the line here. – D.S.

ANSWER: Lisinopril is the generic name for the drug Zestril. It is an ACE inhibitor, a drug that lowers blood pressure by blocking the action of an enzyme that turns a kidney byproduct into a potent substance that raises blood pressure.

The pharmacy switched you to the generic drug, lisinopril. It is the same medicine as Zestril. By giving you the generic drug, the pharmacy was trying to save you money. Such a change is legal unless the doctor specifically indicates that the brand-name drug must be dispensed.

The generic drug lisinopril is manufactured by Mylan Laboratories Inc.

I don’t know if the change from brand-name drug to generic drug caused your reaction. It should not have. Why not have your doctor call both pharmaceutical companies to inquire if there have been any other reactions such as yours? Both companies will be glad to give this information.

DEAR DR. DONOHUE: My 80-year-old sister has osteoporosis pretty bad. She will not take calcium because she says it builds up in her arteries. She has had bypass surgery to provide blood to her heart muscle. I assume that doctors remove fat deposits and not calcium in bypass surgery. Is she right? Is calcium bad for her? – R.P.

ANSWER: Calcium often deposits on the fat-cholesterol buildup on artery walls. The calcium that settles there does not come from calcium in the diet. It comes from body stores of calcium, and it would occur if people ate no calcium. Your sister can take calcium for osteoporosis without fear of clogging her arteries.

Bypass surgery removes neither fat deposits nor calcium deposits. It provides an artificial detour around blockages in heart arteries using segments of clean arteries or veins from other body sites.

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.