DEAR DR. DONOHUE: My dad, 77, has just gotten news that he has multiple myeloma. I know this is a cancer, but beyond that I don’t know anything about it. My mother died seven years ago, and since her death, my dad has not taken care of himself and has been drinking heavily. Could the drinking have caused this? – B.M.

ANSWER: Multiple myeloma is cancer of plasma cells – cells found in the bone marrow and cells intimately involved in the body’s immune defenses.

This cancer is not usually seen until after the age of 50.

The burgeoning population of plasma cells in the bone marrow crowds out other blood cells. Red blood cell numbers take a dip, and that makes patients anemic. The number of white blood cells in the marrow also diminishes, and that is one reason why myeloma patients have frequent infections.

The cancerous plasma cells manufacture a defective antibody. Antibodies coat germs and make them digestible by other immunity cells. The myeloma antibody doesn’t prepare germs for destruction – another reason why infections are so common in myeloma. The peculiar antibody, however, serves a purpose. Detection of it helps confirm the diagnosis of multiple myeloma.

Plasma cells in the marrow not only crowd out other marrow cells, but they weaken bones and lead to fractures. Patients often suffer from broken bones, and the backbones are frequently targets. This produces a great deal of pain for patients.

Predictions of life span for myeloma patients are based on how widespread the plasma cell infiltration of bone marrow is, what the level of the myeloma antibody (protein) is and the extent of bone destruction.

Chemotherapy can lengthen life but not cure myeloma. Bone marrow transplants and stem cell transplants are newer techniques used to control this cancer. Patients’ age determines their usefulness.

Alcohol plays no role in the occurrence of multiple myeloma.

DEAR DR. DONOHUE: My girlfriend breaks out in hives when she is in the sun. That limits what we can do in the summer. Is there any medicine that can stop this reaction? People don’t believe me when I tell them this. – T.L.

ANSWER: The name of your girlfriend’s affliction is “solar urticaria.” “Urticaria” is the official name for hives. Women between the ages of 20 and 40 are the usual victims.

Repeated applications of sunscreens that block both ultraviolet A and B rays can sometimes keep these people hive-free.

Antihistamines taken before going outdoors have been effective for some. Desensitization to sunlight with a program of longer and longer exposure to ultraviolet light can also work.

This is something that ought to be done only in a doctor’s office.

There are a few illnesses that are sometimes seen in association with solar urticaria.

Lupus and porphyria are two examples.

DEAR DR. DONOHUE: I love ice cream, especially in the summer. It keeps me going, and I mean that literally. I get gas and diarrhea after eating one scoop of ice cream. Is this an allergy? – R.W.

ANSWER: More likely it is intolerance to milk sugar — lactose.

People who cannot tolerate dairy products have a deficiency in their digestive tracts of lactase, the enzyme that breaks lactose down for absorption. The undigested milk sugar promotes gas and diarrhea.

You can get around this problem in a number of ways. One is taking the lactase enzyme in tablet form before eating dairy products. Most lactase products instruct people to take the tablet before or with the first bite or swallow of a dairy product.

Many dairy products have been treated to remove lactose from them. Since getting your letter, I have been looking for ice cream that has been made from lactose-free milk. I haven’t found it, but I am positive readers will supply us with that information.

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.