DEAR DR. DONOHUE: I have been diagnosed with Hashimoto’s disease. I never heard of it. I am now taking thyroid medicine but would like more information on this illness. Is it common? None of my friends has heard of it. How does a person get it, and how does a person get rid of it? – M.M.

ANSWER: The thyroid gland is a U-shaped gland, with the bridge between the upward limbs of the U located in the lower part of the neck.

Even though neither you nor your friends have heard of Hashimoto’s thyroiditis, it is a common disorder – the most frequent cause of thyroid gland enlargement (goiter).

An immune attack on the thyroid gland inflames it. The immune system makes antibodies that it lobs at the gland like rocket-propelled grenades. Thyroid hormone production slows. In an attempt to restore hormone production, the gland enlarges, but the enlargement does not revive hormone production.

Without thyroid hormone, all body processes slow to a creep. The skin coarsens and dries. Hair becomes dry and brittle. The affected person is intolerant of cold. What other people consider a normal temperature feels like Antarctica to the person without thyroid hormone. Menstrual periods lose their regularity, and the normal amount of flow stops. The heart beats less frequently. Constipation is the rule. The person loses all energy.

One favorable point in Hashimoto’s is that treatment is straightforward: Supply the missing thyroid hormone in tablets. Symptoms evaporate, and the gland shrinks.

The newly revised edition of the thyroid pamphlet explores all aspects of thyroid diseases. Readers can obtain a copy by writing: Dr. Donohue – No. 401, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.50 U.S./$6.50 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I am scheduled for a prostate biopsy, and I fear it more than I do prostate cancer. How is the biopsy done? Is it painful? What are the risks? I am a basket case over this. – C.R.

ANSWER: You are letting your imagination run wild. I would rather be sailing than having a prostate biopsy, but it is a quick, safe and relatively painless procedure.

The patient lies on his side in the same position many doctors have their male patients assume during a finger examination of the gland.

An ultrasound probe is inserted into the rectum to locate areas where the biopsies will reveal the greatest information.

Another slender instrument, a “gun,” is inserted into the rectum and positioned in the spot where the ultrasound shows the greatest chance of cancer. This sounds like an awful lot of instruments to be introduced via the rectum, but they do not take up much room. When the gun is in place, the doctor activates it, and an array of thin needles obtains tissue specimens from the gland. It is not a procedure borrowed from the torture books of the Dark Ages. It takes only 10 to 15 minutes, it is usually done in the doctor’s office, and you’ll find it surprisingly innocuous.

DEAR DR. DONOHUE: There is a small, red growth next to my armpit. It has been there all my life. It doesn’t hurt or cause me any trouble. It’s a matter of curiosity for me. It looks like a miniature nipple. What could this be? – K.R.

ANSWER: It could be a miniature nipple.

During embryonic and fetal development, a ridge of tissue runs from the armpit to the groin. It is the milk line, and from it the breast nipple grows. About 1 percent of people have an extra nipple or nipples. Most cause no trouble and can be left alone.

Check with your doctor on your next visit. I distrust these long-distance diagnoses of mine.

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.