DEAR DR. DONOHUE: I am the only relative of a spinster aunt who lives in a nursing home. I visit her regularly. The home has had two outbreaks of scabies in the past year. How will I know if I catch it, and how can I prevent that from happening? My aunt has never had it. – R.Q.

ANSWER: Scabies is a mite-caused skin infestation. The mite is tiny – less than 1 mm (0.04 inches) long – so it’s difficult to see. Scabies mites are generally passed from one person to the next through skin-to-skin contact. Meticulous hand-washing can lessen the risk of transmission, but a better solution is to inquire of the nursing home what is being done to prevent these outbreaks. If nothing, then report it to the local health department.

The female mite burrows into the skin and creates a tunnel where she lays her eggs. You’re not going to see the mite without a magnifying lens, but you can see the tunnel, which looks like a red line. The entrance to the tunnel often has a small red bump. The mite likes to burrow in the skin between the fingers, on the wrists, under the arms, on the ankles and at the belt line.

Scabies causes an intense itch that you cannot ignore. The itch intensifies at night.

Scabies is an unpleasant condition, but it’s not the end of the world. Permethrin cream is an effective medicine. Generally if one family member has it, all household members are treated.

Since your aunt has never had it, your chances of getting it are not high. How do you know there have been outbreaks? Have you gotten that information from reliable sources?

DEAR DR. DONOHUE: Isn’t it unusual for a baby to take thyroid medicine? I have a relative whose first baby has had to go on it. Does that run in a family? No one on our side of the family has ever had such a problem, and the mother has been quite healthy. – P.K.

ANSWER: Congenital (born with) hypothyroidism (a poorly functioning or nonfunctioning thyroid gland) often results from something that has gone wrong during fetal development. In a few instances it has a genetic basis, but those instances are few and far between.

Congenital hypothyroidism is not common, but it happens. In the United States, there is one case of it in every 4,000 births.

In times gone by, unrecognized congenital hypothyroidism caused great problems for the infant. If it was not recognized and if no treatment was given in the first three to six months, the consequences were dire. Physical and mental development lagged, and often that lag became permanent even when thyroid hormone was finally given.

Now there are universal screening tests done on newborns for thyroid deficiency. Treatment is started immediately. Early diagnosis and treatment assures normal physical and mental development.

The thyroid booklet provides information on both sluggish and overactive thyroid glands and their treatment. (It does not discuss congenital thyroid problems.) Readers can obtain a copy of the booklet by writing: Dr. Donohue – No. 401, 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: I am a 67-year-old farmer. I have worked hard all my life, and I am still farming. In the past year, I’ve developed pain in my calves when I walk. My doctor thinks my arteries are plugged. How will he tell if they are, and how is it fixed? – R.J.

ANSWER: Your doctor has diagnosed you with peripheral artery (vascular) disease, a very common problem. Close to 10 percent of those in their 60s have it, as do almost 20 percent of those in their 70s. It’s called peripheral artery disease because the affected arteries are in the periphery – the legs or arms – in contrast with coronary artery disease, where the occluded arteries are in the heart.

Leg arteries, just like heart arteries, can become plugged with a buildup of cholesterol, fat, platelets and blood proteins. When a person with this condition walks, leg muscles cannot get a sufficient blood supply to sustain the effort of walking. They become painful. Muscles that are downstream of the blockage are the ones that hurt. Calf muscle pain, therefore, signals obstruction in thigh arteries.

The doctor can pretty well establish the diagnosis by measuring blood pressure at the ankles and comparing it with blood pressure in the arms. Normally, pressure should be the same at the two sites. If ankle pressure is lower than arm pressure, that indicates there’s an obstruction in the leg arteries.

Treatment of peripheral artery disease follows the same regimen followed for treatment of heart artery disease. Cholesterol has to be lowered. Blood pressure must be controlled. Weight loss, if applicable, is necessary. Exercise is most important; this is something you do routinely, so stay with your work, just as you have been doing.

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.