DEAR DR. DONOHUE: Please give me some information on sarcoidosis. – H.J.

ANSWER: That’s the shortest letter I have ever received. Sarcoidosis is an illness in search of a cause. That cause has so far proven elusive. What is known is that something has turned on the immune system. It functions at a high level and draws white blood cells and other body cells into organs as advance scouts. Inside the organ, those cells die and aggregate into mounds called granulomas.

In North America, sarcoidosis affects blacks more than any other ethnic group, another unexplained fact of this illness.

Sarcoidosis can strike any organ, but the lungs take the brunt of the damage. Liver, skin, eyes and lymph nodes are other major targets.

For some, no symptoms develop. The illness is discovered when a chest X-ray is taken for unrelated reasons and the changes of sarcoidosis are seen. Others experience an abrupt illness with fever, loss of appetite, weight loss, dry cough and difficulty breathing. In still others, the illness comes on more slowly and the salient features are hacking, dry cough and shortness of breath.

In some, the illness clears in time. Others are left with a degree of impairment that still permits them to carry on most of life’s activities. In a smaller number, there are persistent and often disabling symptoms.

Usually doctors hold off on treating newly diagnosed sarcoidosis for a couple of months to see if the illness disappears on its own. If it doesn’t go away or if symptoms are bad, the medicine most often prescribed is prednisone, one of the cortisone drugs.

Why did you ask this question?

DEAR DR. DONOHUE: My husband has severe rheumatoid arthritis. He is 43 years old and has been afflicted with it since he was 26. Due to many factors, including stopping medication twice so I could get pregnant safely, he has tremendous damage to all his joints. His hands, knees and feet are the most adversely affected, although his neck, spine and other joints have some damage.

What worries me is his sedentary lifestyle. He gets no exercise at all. He spends most of his time lying down or playing video games. What can he do to combat fatigue and muscle loss and maintain heart health? – S.S.

ANSWER: With the extent of joint damage your husband has, the best course for him is to consult a physical therapist, who can assess his capabilities and devise a safe exercise program, one that won’t injure his already damaged joints. Exercise is important for him. It’s important to increase muscle strength. Strong muscles protect joints and permit a range of motion that he might not believe he has.

He should also see an occupational therapist. These therapists are medicine’s unsung heroes. An occupational therapist can show him how to perform life’s daily tasks, tasks he might not now be doing. An O.T. can demonstrate the working of devices your husband has no knowledge of, devices that can help him perform actions he cannot get done on his own.

Even severely affected arthritics can usually perform water exercises. Water’s buoyancy cushions joints, and feats that are impossible on land can be done in water.

The arthritis booklet describes both rheumatoid and the more common osteoarthritis and their treatments. To obtain a copy, write: Dr. Donohue – No. 301, 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: I starting taking Relafen for joint pain. I have been on blood pressure medicine for five years, and my blood pressure was controlled until I started the Relafen. Could it be the reason my pressure has risen? – R.K.

ANSWER: It could be. Some of the nonsteroidal anti-inflammatory drugs, of which Relafen is one, can cause fluid retention and a rise in blood pressure. Tell your doctor what’s happening.

DEAR DR. DONOHUE: Does soaking in a tub of warm water really promote sleep? My wife insists it does. If you agree with her, I’ll try it. I do need sleep.

ANSWER: It works for many.

There’s some science behind the idea. Upon getting out of the warm water, you’ll have a rapid drop in body temperature. That’s a signal to the brain to put the body into a sleep mode.

You’ve nothing to lose by trying 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