DEAR DR. DONOHUE: Will you please explain what cat scratch fever is? Is there another medical name for it? What causes it, and what is the treatment? – R.G.

ANSWER: Cat scratch fever is more often called cat scratch disease, but whichever name you like is fine with me. It’s caused by a bacterium whose name is Bartonella. That germ leaves the cat unscathed, or it gives it an illness similar to the human illness. Cats can carry the germ for years.

In humans, children are the ones who most often contract the illness from a scratch or bite, usually of a kitten. Not every cat scratch or bite, even from an infected cat, causes illness, and for most people, the illness is a mild one. About seven to 12 days after a scratch from an infected cat, a small red bump springs up at the bite location. It looks like a mosquito bite. Anywhere from five to 50 days after the scratch, lymph nodes that drain the scratched area swell and are tender. Since most scratches are on the arms, nodes in the armpits are the ones most often involved. The person might have a fever, and some complain of a sore throat and headache. The majority, however, don’t feel ill.

Just about everyone gets better without any treatment, but it can take months before the lymph nodes return to normal size.

For the small number of people who become quite ill, antibiotics are prescribed, but which is best is debatable.

DEAR DR. DONOHUE: I was told that I have a pituitary gland tumor. I haven’t had a menstrual period for three years, and I am 40. My concern is that I have had severe back pain for the past two years. Could this be related to the tumor? – T.K.

ANSWER: The pituitary gland is a small gland, weighing less than 0.04 ounces (0.5 to 1 gram), but it has huge responsibilities. It makes its own unique hormones, and it makes hormones that regulate many other endocrine glands, like the thyroid and adrenal glands, the ovaries and the testes.

Pituitary gland tumors are almost never cancerous, but they can cause trouble in two different ways. For one, they can produce excessive amounts of hormones. Depending on the hormone the tumor produces, it can lead to an overactive thyroid gland or adrenal gland, or it can make the breasts leak milk due to an overproduction of milk-stimulating hormone, or it can cause many other profound disturbances. On the other hand, if the tumor doesn’t produce hormones, its size can shut down pituitary gland production, and one of the results can be a loss of periods. A large tumor can also compress adjacent brain structures, like the optic nerves. That brings on serious visual problems.

I don’t know if your pituitary tumor has done anything to you other than stop your menstrual periods. Symptoms from such tumors can be numerous. Back pain, however, isn’t a common pituitary tumor symptom.

By stretching things, I can make a weak case for back pain being related to a pituitary tumor. Sometimes such a tumor can be linked to osteoporosis, which, in turn, can be a cause of back pain. But the link is weak, and I really doubt that your tumor is the cause of your back pain.

DEAR DR. DONOHUE: Help me! I am 83 and have a daughter who’s 63. For the past 30 years, she has kept herself tanned. This year she is very brown.

Will all this tanning help her? Will it make her sick? Can she do this every year? I don’t like it. – M.P.

ANSWER: Your daughter’s love of tanning has become an obsession. Too bad your daughter didn’t inherit her mother’s common sense.

Tanning is an attempt by the skin to protect itself from the sun’s ultraviolet rays. Those rays lead to skin cancer, wrinkles, dry skin and prematurely aged skin. In short, tanning isn’t healthy.

You can show this to your daughter, but I don’t know if it will change her mind. People who are devoted tanners rarely listen to opinions about its unhealthy consequences.

DEAR DR. DONOHUE: Please, please, please answer this letter for me and my fellow seniors. Constipation is a daily topic of conversation. We tried bran, stool softeners and your recipe, but the only thing that works is a laxative. Will we eventually become immune to the benefits of a laxative? – S.C.

ANSWER: Frequent laxative use once sent a shudder through the medical community. Now laxative fear is not such an issue. If you need one, take one. You won’t become immune to its effects. Keep in mind what constipation is. A daily bowel movement isn’t necessary. Having fewer than three a week and having rock-hard stool is considered constipation. Examine your medicines to see if any of them are constipating. Many blood pressure medicines, calcium carbonate, some diuretics and some nonsteroidal anti-inflammatory drugs are constipating medicines.

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