DEAR DR. DONOHUE: What causes nosebleeds? For the past month or so, the right side of my nose bleeds for a short time about once a week. If I lie down with my head held back for a few minutes, it stops. — C.P.

ANSWER: The largest number of nosebleeds originate from the nasal lining in an area slightly inward from the nostril and on the nose’s middle partition, the nasal septum. That’s the place where many blood vessels converge. If the nasal lining dries, it flakes off, and the blood vessels bleed from the slightest touch. Drying is prevalent in wintertime, when the humidity of furnace-heated homes plummets. And aspirin, widely used for heart attack and stroke prevention, makes its contribution to nosebleeds.

If your way of stopping the bleeding works for you, stick with it. Most authorities suggest bending the head forward so that blood doesn’t trickle down the throat. Pinching the sides of the nose firmly together between the thumb and index finger for 15 minutes can stop most bleeding. Keep your nasal lining moist by applying a very light coat of petroleum jelly to it every day — only to the area I mentioned. Keep your home’s humidity between 40 percent and 60 percent.

Serious causes for nasal bleeding have to be considered when the bleeding occurs often and when it is heavy. Clotting disorders, infections, a deficiency of blood platelets and an inherited condition called hereditary hemorrhagic telangiectasia are some of those conditions. High blood pressure is often cited as a cause. It appears not to start spontaneous nosebleeds, but it can keep a bleeding nose bleeding longer and more heavily.

DEAR DR. DONOHUE: After being a big dairy eater all my life, I have developed a problem digesting it in the past several years. I have cut back on it to the point where I take only a little bit in the morning. I think I have reached a point where I cannot take any dairy at all. It causes me a lot of gas, and I notice a discharge from my bladder and rectum. Is this lactose intolerance? — P.K.

ANSWER: In infancy, our digestive tracts have plenty of lactase, an enzyme that digests lactose, milk sugar. As we get older, the amount of lactase in the digestive tract wanes, and many people find it difficult to handle milk products. That condition is called lactose intolerance or lactase deficiency. Either one is correct. Symptoms are diarrhea, crampy abdominal pain, bloating and an increased production of gas.

Lactose intolerance never causes a bladder discharge. It can cause a discharge of rectal mucus. Most adults retain the ability to digest a glass of milk. For those with greater depletion of the lactase enzyme, they have to forgo milk and cream. They might be able to digest cheese. Most tolerate yogurt. The use of tablets containing lactase prior to eating dairy products can permit people with this condition to liberalize their diet. DairyCare, Dairy Ease, Lactaid Fast Act and Lactrase are the names of some lactase-containing products.

Doctors can test patients for lactose intolerance with a couple of office tests. One is the lactose tolerance test, which is very much like the glucose tolerance test used to detect diabetes. Another is the lactose breath hydrogen test. It measures the amount of hydrogen produced after a person takes lactose. You should consult your doctor about your problem in order to settle the question of lactose intolerance.

DEAR DR. DONOHUE: When my brother became bedfast and eventually died, his son, my nephew, quit his construction job to care for him. He developed a phobia of being around people. He cannot get to a doctor. When he’s with people, he has panic attacks. He’s wasting his life. What can be done? — E.F.

ANSWER: Your nephew can be helped with counseling and medicine. Even someone as crippled by panic attacks as he is has to resolve to see a doctor. Often, people like your nephew can manage such an excursion if they’re accompanied by a friend or a relative. His chances of getting better are good if he can motivate himself to take this plunge.

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.