DEAR DR. DONOHUE: Please explain why I have to take my shoes off late every day because my feet and ankles have swollen and don’t fit into the shoes. I flop around in slippers without heels. In the morning, after a night’s sleep, my feet are back to normal. I am 77 and take no medicines. — K.M.

ANSWER: I can’t give you an unequivocal response because there are numerous causes of foot and ankle swelling.

The medical name for such swelling is edema. Even in relatively healthy people, it occurs if people sit or stand for any length of time. Gravity pulls fluid out of the circulation, and it accumulates in the feet and ankles. This is especially true at older ages, when the circulatory system becomes somewhat leaky. For this kind of swelling, the solution is to elevate the legs when sitting. The most effective elevation is raising the legs above heart level, something that can be done only by lying down with pillows propping up the legs. Getting up and moving about is another way to prevent fluid accumulation in the feet.

Heart failure is a more serious cause of such swelling. When the heart’s pumping action becomes feeble, fluid escapes from blood vessels and again accumulates in the ankles and feet. Kidney disease with retention of body fluid is another cause of edema. Liver disease does the same.

Another condition called lymphedema produces the same picture. Lymph is fluid that normally escapes the circulation to percolate around tissues and organs to provide nourishment and to wash away germs. Small vessels called lymphatics vacuum up this fluid and return it to the circulation. Anything that disrupts lymphatics can lead to ankle/foot swelling. An old infection and surgery are two such disruptors.

Since ankle and foot swelling is a sign of many urgent medical conditions, don’t fool around with this. See your family doctor.

The booklet on edema and lymphedema clearly describe these conditions and their treatment. Readers can obtain a copy by writing: Dr. Donohue — No. 106, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I have a small lump on the back of my left wrist. It’s soft and doesn’t hurt even when I push on it. It’s been there for at least two months. I don’t remember injuring it. Lumps freak me out. My brother had bone cancer. When I see things sprouting on me, I think of cancer. Could it be? — F.L.

ANSWER: It’s not likely to be bone cancer. A more likely bet is a ganglion. That’s a kind of cyst filled with thick, gelatinous material. It communicates with the wrist joint or with one of the wrist tendons. If it doesn’t hurt or interfere with wrist motion, you can ignore it. It if does, a doctor can remove it without much fuss. Many ganglion patients want their doctor to drain it. Drainage is possible, but the recurrence rate is very high.

DEAR DR. DONOHUE: My 18-year-old daughter is a ballerina and a gymnast. She’s as skinny as a rail, which helps her in both fields. She tells me her menstrual periods, which used to be quite regular, have now stopped. She isn’t pregnant. She was tested for that.

She’s not the least concerned about not having periods. I wonder what it’s doing to her health. Could this affect her in some way that might be harmful? — R.R.

ANSWER: A female must have a certain amount of fat to support the production of female hormones that bring about menstrual periods. One harmful consequence of insufficient amounts of female hormone is osteoporosis at an early age.

I don’t know your daughter’s height and weight. However, she should try to gain at least 10 pounds. If, on gaining weight, her periods don’t resume, she’ll need to see a doctor. Insufficient weight is only one cause for the loss of periods. There are many others.

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.