DEAR DR. DONOHUE: My daughter, who has rheumatoid arthritis, is now told by her doctor that she has it in the wall lining of her chest, and this was confirmed by another doctor. I have never heard of it before and would like to have any information you can give me. My daughter is only 24. She has terrible pain in her chest at times and trouble breathing. - Mrs. J.B.

ANSWER: Rheumatoid arthritis is not an illness of joints alone. It is what we call a systemic disease, meaning that many body tissues and organs may also be affected by the basic inflammation process.The lining tissue to which you refer is the pleura. It comprises delicate covering tissue that protects the lung surface, also allowing for the expansion and contraction that goes on with each breath. Some people with rheumatoid arthritis do develop this pleural inflammation - pleuritis. An inflamed pleura causes great pain as it moves with movement of the breathing muscles.

Viral infection is another cause of pleuritis. When that infection subsides, the inflammation and pain do also. By the same token, when you relieve the arthritis inflammation, pain from that should subside. The arthritis report will answer other questions you have. Others may order by writing Dr. Donohue/No.2, Box 830, Gibbstown, NJ 08027-9909, enclosing a long, stamped, self-addressed envelope and $2.

DEAR DR. DONOHUE: My husband has a problem with his hair. On his left side behind his ear he has a spot that is increasingly becoming bald. He has very thick hair otherwise. The spot was first noticed a month ago. It was the size of a quarter. It has been three months and it is now the size of a silver dollar. There's very little hair in this spot, but it looks like a few hairs might be trying to come back. He has seen a doctor, who had a big name for it, beginning with an "A." He said not to worry, no real cause, no real solution. He said his hair would come back. Please help. He doesn't know who to contact about it. - Mrs. J.O.

ANSWER: Does the term "alopecia areata" ring a bell? I'm pretty sure this is what the doctor mentioned. In this, hair is lost in one or more round patches. One theory of cause involves a mounting of a localized immune assault on the hair follicles.

There is a high probability of regrowth, and what you may be noticing of late is the beginning of that. If the process is taking too long for your peace of mind, you can see a dermatologist, who can inject the area with cortisone-type drugs. That's one treatment for alopecia areata.

DEAR DR. DONOHUE: Is it possible for the thyroid test to be normal while the one for the parathyroid is not? - Confused

ANSWER: These two glands are both in the neck area quite close to each other. In fact, the parathyroids adhere to the larger thyroid. Yes, it is possible to have normal thyroid activity while the parathyroid tests show abnormal function.

The thyroid gland regulates body metabolism in general, while the parathyroids control blood calcium levels. The function tests for the two glands are separate. It appears from your longer (edited) letter that you are somewhat confused by all these tests you speak of. Better have a long talk with the doctor about their significance.

DEAR DR. DONOHUE: Can you tell me about histoplasmosis - the cause, symptoms, cure? Also, can it be contracted through the air from local chicken manure in a neighbor's fields? - K.P.

ANSWER: Histoplasmosis is one of the most common of fungal infections. It is especially prevalent in the Mississippi, Ohio and St. Lawrence river locales. The fungus does grow in soil, and especially in soil enriched by bird droppings. The organism releases spores into the air, where you can breathe them in.

The symptoms vary in severity. A few people develop flu-like feelings, which go away on their own. Fewer still get quite sick and need treatment. Amphotericin is one of the drugs used. It is given intravenously.

I would think that if the fungus were present in a nearby manured field it might also be found in your own soil as well. Incidentally, the manure itself does not contain the fungus inherently. It only enhances its growth in the soil.

Dr. Donohue welcomes reader mail but regrets that, due to the tremendous volume received daily, he is unable to answer individual letters. Readers' questions are incorporated in his column whenever possible.