DEAR DR. DONOHUE: I want your opinion on lupus. I was diagnosed with it four years ago, but I’m starting to think I might not have it. Last year I went nine months without any medication, and I was working out and eating healthy. I doubt I have lupus. I’m supposed to have the rheumatoid one.

I need information on lupus. And can you tell me what is the best medicine for it? — S.

ANSWER: I take you to mean systemic lupus when you say “rheumatoid.” That’s the kind of lupus that affects joints, like rheumatoid arthritis.

A total of 11 signs and lab tests are used to detect lupus. They include skin rash, sun sensitivity, arthritis affecting two or more joints, kidney involvement such as finding protein in the urine, anemia, seizures, oral ulcers and unique antibodies in the blood. Four of these signs and tests are enough evidence to make a diagnosis of lupus. Fatigue, weight loss and fever are other indications of it.

Lupus consists of cycles when it worsens and cycles when it improves. A cycle can last for a year or longer. You might be in a cycle where signs and symptoms have all but disappeared.

Or you might be right — the diagnosis could be erroneous.

The only way to confirm your suspicion is to consult a doctor either now or when and if lupus symptoms recur.

The best lupus medicine? Medicines used for lupus are prescribed on the basis of its severity and whether internal organs like the heart, lungs and kidney are affected. Plaquenil (hydroxychloroquine), prednisone (a cortisone drug) and methotrexate have been used for years. Newer medicines such as rituximab are used when the older, standard medicines do not control this illness.

DEAR DR. DONOHUE: My wife had two small TIAs several years ago. She takes Plavix to prevent a stroke.

Every time she even slightly hits her legs or arms, she ends up with unsightly bruises. I notice that many seniors have them too.

Aside from being more careful, which my wife says she is, what can be done to avoid these bruises? — W.S.

ANSWER: Bruises result when blood leaks out of blood vessels. In your wife’s and many others’ case, they come because the tiniest and most fragile blood vessels break. Those vessels are capillaries. At older ages, the padding around capillaries and their supporting tissues are not as sturdy as they are in youth. A slight bump leads to bruising. Protecting the arms and legs is the only prevention. Most people are not willing to encase themselves in padding that makes them feel like they’re wearing a suit of armor.

Your wife’s Plavix, a medicine that stops platelets from forming a clot when a blood vessel breaks, also encourages her bruising. She has to take it to ward off a stroke. I wish I could offer her more helpful advice. I can’t.

DEAR DR. DONOHUE: My son is 57. He has a very fast heartbeat. I don’t know when it started, but he has had it for many years. Can you put light on what may cause this? Is it anything to be concerned about? No doctor has ever mentioned it to him. — E.A.

ANSWER: How fast is your son’s heart beating when he’s sitting and resting? A normal rate is in the range of 60 to 100 times a minute. Heartbeat and pulse are the same thing. He can take his pulse on the thumb side of the wrist, or he can count his heartbeat by putting his hand on the lower chest and counting the beat.

Anemia, an overactive thyroid gland, anxiety, deconditioning and lung diseases are some of the problems that speed the heart.

If your son sees a doctor regularly and if he has no symptoms, like breathlessness or chest pain, then most likely all is well. If he hasn’t seen a doctor in some time or if he has any symptoms, he needs an exam if his heartbeat is out of the range I mentioned.

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.