DEAR DR. DONOHUE: My wife and I had urinary tract infections this past month. She took antibiotics at home and did well. I had to go to the hospital and get antibiotics by a drip into the vein. Why the difference? Are urinary tract infections worse in men than in women? – G.M.

ANSWER: Urinary tract infections are divided into upper and lower tract infections. The lower urinary tract includes the urinary bladder and the urethra, the drainage tube that empties urine from the bladder to the outside world. Usually only the bladder is involved, and such an infection is called cystitis. Upper urinary tract infections are infections of the kidneys. The name for this kind of infection is pyelonephritis.

Cystitis is much more common in women. Part of the reason is their short urethras. Bacteria can easily crawl into a woman’s urethra and quickly arrive at the bladder. Men’s longer urethras make such an invasion much more difficult.

By age 24, one in three women has had a bladder infection. They are rare in men of that age. Older men, because enlarged prostate glands make complete bladder emptying nearly impossible, have greater rates of cystitis. Stagnant urine favors the growth of bacteria.

You must have had pyelonephritis – infection of the kidney. These infections are quite serious. Unlike bladder infections, they produce high fevers and shaking chills. Patients become nauseated and frequently vomit. Pain at the sides of the back can be intolerable.

This sort of urinary tract infection almost always calls for hospitalization. A large amount of antibiotics has to be given quickly to preserve kidney function, hence the IV drip.

Men and women equally get pyelonephritis. It does not favor one gender over the other.

The pamphlet on urinary tract infections clears the air about these common disorders. Readers can order a copy by writing: Dr. Donohue -No. 1204, 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: For months I had an itchy rash at my right elbow. I tried to treat it by myself with salves I found in the drugstore. Nothing worked. A skin doctor tells me I have dermatitis herpetiformis and has me on a medicine that has worked wonders. I forgot to ask the doctor if this is catching. Is it? – T.M.

ANSWER: Dermatitis herpetiformis, in spite of the “herpes” in the name, is not an infection. You cannot spread it.

It’s a patch or patches of itchy skin, most frequently seen on the elbows, knees, scalp, neck or shoulders. The patch can be full of small red bumps or tiny blisters.

Is your medicine dapsone? It often brings quick relief.

The strange aspect of this skin disorder is its linkage to a digestive tract problem – celiac disease. They often appear together. It might be that the skin rash reacts to the same antibodies that attack the small intestine in celiac disease. The symptoms of celiac disease include weight loss, abdominal pain and diarrhea. Because minerals and vitamins are not absorbed, celiac patients often have an anemia.

A gluten-free diet is a must for people with celiac disease, and it might also work for those who have only dermatitis herpetiformis. Gluten is a protein found in wheat, barley and rye, and learning how to avoid it takes detailed instructions from a dietitian.

Let all your doctors know about your skin diagnosis. They will all want to watch for any symptoms of celiac disease.

If dermatitis herpetiformis keeps coming back, you might want to try the gluten-free diet. It might be the way to prevent recurrences.

DEAR DR. DONOHUE: I am just recovering from a week of diarrhea. I had the flu shot. How come I came down with it? – J.C.

ANSWER: You didn’t have the flu. Flu – influenza – is a respiratory infection with cough, raw throat, sore muscles, intense headache and fever. Diarrhea is not one of its symptoms.

People always speak of intestinal flu. I don’t know how that phrase got started. It’s OK to use it if you realize that the flu shot is not a prevention for intestinal infections.

DEAR DR. DONOHUE: I have a question to ask for my sister-in-law. She injured her back months ago. When I saw her a few weeks ago, she seemed perfectly fine. She moves fast and with no pain. She is 44. The doctor told her she has arthritis and spina bifida. She’s keeping this from her mother so as not to worry her. The rest of the family is very concerned. What is spina bifida? – D.S.

ANSWER: Picture St. Louis’ landmark arch. Backbones (vertebrae) look somewhat like that arch. If the central top part of the arch was missing, then the arch would be a model of spina bifida. When only the small section of bone is missing, spinal bifida usually causes no troubles.

A more serious condition is spina bifida with a meningocele (men-IN-go-seal). That’s a backbone without its central part and with a bulging of the spinal cord coverings, the meninges, through the bony gap. This situation can present many problems.

An even more serious condition is spina bifida with myelomeningocele. Here, not only the spinal cord coverings but the spinal cord itself bulges through the gap. Such a condition usually produces grave complications.

You and your family can relax. Your sister-in-law’s spina bifida is unlikely to be a source of pain now or in the future.

Unrelated to this question is a piece of information that needs to reach the public. Women of childbearing age ought to be taking 0.4 mg of folic acid daily to prevent spinal cord defects like those listed above. Folic acid is a B vitamin. Women who are planning a family must have a full supply of the vitamin in their bodies from day one of pregnancy. That’s why they must take it all the time.

The back pamphlet, although it doesn’t discuss spina bifida, does discuss common back problems that cause so much disability and pain. Readers can obtain a copy by writing: Dr. Donohue – No. 303, 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.

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.