DEAR DR. DONOHUE: I am writing about fifth disease. I never heard of it when my children were growing up. My grandchildren have had it. What is it? Can they get it more than once? – C.K.

ANSWER: About 100 years ago, a list of illnesses, all of which had similar red rashes, was drawn up. On the list were illnesses like measles, scarlet fever and rubella (German measles). The fifth illness on the list was simply called fifth disease. Not until 1974 was the cause of fifth disease discovered – parvovirus B 19. The illness has another name – erythema infectiosum – but “fifth disease” is the more popular designation.

It’s mostly a childhood illness. By age 15, half of all children have been infected. For some, the illness is so mild, no one suspects they have it. Others develop a fever, have a drippy nose, complain of headache and sometimes come down with diarrhea. Two to five days after those symptoms appear, the child’s cheeks turn fiery red, as though they had been slapped. A few days later, a rash might break out on the trunk. The rash can last for a week or more.

Usually a child has only one infection of fifth disease. The rash can recur, however, for some weeks after all the original signs have disappeared.

Adults – especially young women – who become infected with the virus most often do not come down with a rash. They can have painful joints, particularly of the hands and feet. The joints hurt for one to three weeks, but the pain can return again and again for months.

DEAR DR. DONOHUE: My sister recently passed away from a stroke. She could not swallow or walk. What caused this, and could anything have helped her? – A.P.

ANSWER: Strokes come from an interruption of blood flow to the brain. The blockage can be in one of the large neck arteries or in one of the smaller arteries within the brain. A smaller number of strokes come from an artery that bursts and hemorrhages into the brain. I’ll talk only about the blockage kind of stroke.

If brain cells are deprived of blood, they die in 4 to 10 minutes. Brain cells surrounding the dead cells teeter on the brink of death, but they can be revived if blood flow is again established, and that minimizes the impairments that follow a stroke.

Clot-dissolving drugs, when given within three hours of a stroke, can limit the amount of damage done to the brain. One of those drugs is tPA. It is most important for people to recognize stroke symptoms so they can get the stricken person to a hospital quickly. The list includes: numbness or weakness of the face, arm or leg, especially on one side; sudden confusion, loss of memory or loss of consciousness; difficulty talking or understanding spoken or printed words; sudden loss or blurring of vision; difficulty walking or problems with balance; dizziness; and sudden, severe headaches.

The booklet on strokes and stroke recovery covers the topic more thoroughly. Readers can obtain a copy by writing: Dr. Donohue – No. 902, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: I have something on my tongue. Many years ago it used to be called thrush. I have taken various medicines, but I have not been able to get rid of it. Do you have any suggestions? – G.Y.

ANSWER: The candida yeast causes thrush. It produces creamy-white, curd-like patches on the tongue, inside the cheeks and in other places within the mouth. If you scrape a patch, it bleeds.

Quite a few medicines are usually successful at eliminating thrush. Among them are nystatin mouthwashes, clotrimazole lozenges, and fluconazole, ketoconazole and itraconazole, all of which come in many forms.

If these medicines aren’t successful, the dentist or family doctor should scrape the tongue and examine the scrapings with a microscope to confirm the presence of the candida yeast. Other conditions can give rise to white patches in the mouth that look something like thrush but have entirely different treatments.

DEAR DR. DONOHUE: Will you write about undulant fever? I had it years ago. It seems the doctors in the state I have moved to have never heard of it. – H.D.

ANSWER: Undulant fever also goes by the name “brucellosis.” It was once a somewhat common infection in the United States, but now there are less than 100 cases a year, so most doctors have had no experience with it. It is acquired through contact with infected animals or their secretions. The germ gets into people through cuts, through breathing it in or through eating or handling foods contaminated with it.

The illness causes waves of high fever. “Undulant” is derived from the Latin word for waves. Severe back pain is often a prominent feature, as are headaches and profuse sweating. Bones, joints, skin, eyes, kidneys and even the heart can be involved. The antibiotic doxycycline along with rifampin or streptomycin usually effects a cure.

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.