DEAR DR. DONOHUE: I am 71 and still suffering from hot flashes. Isn’t this unusual? I don’t know a single woman of my age or 10 years younger who still has them. Why do I? What can I do for them? — R.J.

ANSWER: Menopausal hot flashes come from a flood of warm blood into skin blood vessels. The heat wave lasts one to five minutes and affects mostly the upper body and face. Sweating often is part of the picture. Hot flashes usually subside in one to five years. However, up to 10 percent of women have to contend with them for 10 or more years. You aren’t alone. Why they last so long in some women is inexplicable.

The hot flashes come from a malfunction of the brain’s thermostat. Either a decrease in estrogen or a rapid fluctuation in estrogen blood levels apparently upsets the thermostat. Other investigators think hot flashes are due to a disturbance in the production of brain messenger chemicals, chemicals like serotonin and norepinephrine.

Estrogen relieves hot flashes. However, estrogen replacement increases the risk of breast cancer, heart attack and stroke, so doctors and patients are reluctant to use it. Small doses of estrogen for a short time are not so dangerous. You can discuss the matter with your doctor.

Other medicines can be used in place of estrogen. Clonidine is one. Prozac and Paxil, both antidepressants, regulate the production of brain messenger chemicals and have found a place in the control of hot flashes. So has Neurontin, a medicine mostly prescribed for seizure control

Avoid alcohol, spicy foods, hot drinks and caffeine-containing beverages and foods.

Your doctor has to look for the rare causes of hot flashes, such as thyroid troubles, hidden infections, stress and rare tumors called carcinoid and pheochromocytoma.

DEAR DR. DONOHUE: Is there anything you can tell me about a Tarlov cyst on my daughter’s spine? It’s about the size of a quarter. I have asked you four times. I take it you don’t know. — Anon.

ANSWER: I did answer you. Maybe the answer didn’t appear in your paper. I’ll have another go at it.

Tarlov cysts are sacs filled with spinal fluid. They form on the lowermost parts of the spinal cord. Many people have them, but only a few suffer from them. Large cysts press on nerve roots to cause back pain and impair leg movement. They also might cause headaches. Your daughter has a large cyst.

If your daughter’s cyst is painful, a Lidoderm patch might be a way to ease her pain without resorting to more-invasive treatments. The patch contains the numbing agent lidocaine.

The cyst can be drained with a needle and then injected with fibrin. Fibrin is a natural body protein that is somewhat sticky, and it can keep the cyst sealed tightly.

If all else fails, surgical removal of the cyst is considered.

DEAR DR. DONOHUE: All my life I have suffered from bowel problems. When I was young, I was constipated. Now, in my 70s, it is diarrhea. In my youth I found relief with blackstrap molasses. It was a natural, wonderful solution.

Now, after many tests, my doctor has prescribed cholestyramine for my diarrhea. It works wonders, but it brought back the constipation. I have solved the problem by taking cholestyramine in the morning and night and blackstrap molasses at the same time. I adjust the amount of each until I solve the problem for that day. Every day is different. — J.H.

ANSWER: I’m glad you’ve found a remedy for your problems. I can’t vouch that it will work for others as well as it has worked for you. Wouldn’t adjustment of the cholestyramine dose stop diarrhea and prevent constipation?

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.