Dear Doctor: My daughter took her kids to the pediatrician the other day for their chickenpox vaccinations. Now, because I had chickenpox as a child, she's after me to get a shingles vaccine. What is shingles, and what's the connection to chickenpox?

Dear Reader: The same virus that causes chickenpox is responsible for shingles, a painful rash that can cause long-term problems. It's possible to get shingles at any age, but it's most common in adults 60 and older.

Here's what happens. Once the fever, rash and body aches of a bout of chickenpox have ended, the virus that caused the illness, called varicella-zoster, stays in the body. It lies dormant near bundles of nerve along the spine, known as the dorsal root ganglia. These are the nerves that pass sensory information -- a touch, a tickle, the pain of a bee sting -- from your skin to your brain.

Years after the initial infection, for reasons that still aren't entirely clear, the virus can become active again. As it begins to reproduce, the body reacts. Some people get flulike symptoms such as headache, sensitivity to light and a general feeling of illness. Others notice their skin is becoming tingly, itchy or painfully sensitive.

When the shingles rash appears, it's generally along only one side of the face or torso. It can look like a stripe, as it traces the path of the affected nerves. Tiny blisters form and re-form on the skin, and last for two to four weeks.

During this period the person with shingles is contagious. He or she can pass along a case of chickenpox -- but not shingles -- to anyone without immunity. The virus can be spread by direct contact with fluid from the rash. That's why anyone with shingles should steer clear of pregnant women, infants, unimmunized children and individuals with suppressed immune systems.

If shingles sounds like a difficult and unpleasant illness, you're right. During a case of shingles, even the touch of fabric on the affected skin can cause pain. The most common side effect is a condition known as postherpetic neuralgia, in which the severe pain of shingles persists for months or even years.

The good news (we imagine that you're ready for some about now) is that there is a shingles vaccine. It's made of live varicella-zoster virus that has been greatly weakened. It's enough to stimulate an immune response in your body, but not enough to cause problems in anyone with a healthy immune system.

We routinely recommend to our patients who are 60 or older, and whose immune systems are in good order, that they get a shingles vaccine. Protection lasts about five years. Some drugs, such as those for rheumatoid arthritis, as well as some cancer drugs, suppress the immune system. In these cases, the shingles vaccine should be avoided. There are other contraindications as well, so talk it over with your primary care physician to make sure a shingles vaccine is the right decision for you.

For those who do get the vaccine, it's important to note that it doesn't guarantee you will never get shingles. What it does is measurably lower your risk. And if you do still get shingles, the vaccine also reduces the likelihood of developing postherpetic neuralgia.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: I just read your column about a daily aspirin regimen, which raised these questions for me: If someone appears to be in the middle of a heart attack, should you try to give them an aspirin? Also, does it pay to keep aspirin in the house just for that purpose?

Dear Reader: To answer your questions, let's first review how heart attacks happen. They are caused by a sudden decrease of blood flow to the heart via the coronary arteries. Although a heart attack can happen suddenly, the risk rises over time if you have vascular damage to the lining of these arteries. That damage, termed atherosclerosis, occurs when cholesterol and other substances form plaque inside the coronary arteries, causing them to narrow.

When plaque in one of the coronary arteries is disrupted, small particles in the bloodstream called platelets attach to one another at the area of the disruption and form a blood clot. This blood clot causes a sudden lack of blood flow to the muscle of the heart and thus a lack of oxygen to the heart, preventing that portion of the heart from working. Even worse, without oxygen, that portion of heart muscle will die. That is termed a heart attack.

Aspirin targets the platelets at the core of these clots. Platelets clump together at the site of a wound. Usually, that's a positive. Any time you get a cut in your skin, these platelets activate and attach to one another to stop the bleeding. Aspirin reduces these platelets' ability to attach to one another. In heart disease, aspirin works to prevent clots, but also to prevent the clots that have formed from becoming worse.

The first large study to show a benefit from aspirin among people suffering from a heart attack was a 1988 study published in the medical journal Lancet. As part of this study, researchers gave people who had recently had symptoms of a heart attack either aspirin or a placebo. The aspirin was given at least 24 hours after the beginning of symptoms, with the median time being five hours after onset. These people continued aspirin at 162.5 mg (1/2 dose of a full aspirin) for 30 days.

The measured death rates at five weeks of the 8,587 people who took the aspirin showed a decrease in death from vascular disease of 23 percent, compared to the 8,600 in the placebo group. It is difficult to know how much of this benefit was from the immediate aspirin and how much was from the daily aspirin given for 30 days.

In healthy people taking aspirin, the anti-platelet impact takes effect about 20 minutes after swallowing the compound. But in those who are having a heart attack, the absorption of aspirin decreases, so that it may take up to two hours for aspirin to have the same effect. A 2002 study in Israel that was published in the American Journal of Cardiology showed lower death rates among people who were given aspirin sooner rather than later. The earlier users in this study received aspirin on average 1.6 hours before the onset of symptoms.

The American Heart Association recommends immediate aspirin be given at doses of 160 to 325 milligrams to people with symptoms of a heart attack. Because of the decrease in aspirin absorption in those having a heart attack, the recommendation specifies that the aspirin be chewed.

If someone around you is having a heart attack, the most important thing is getting that person to the hospital. If you have an aspirin, give it to the person immediately and have him or her chew it.

And, to answer your question: Yes, it would be a good idea to have aspirin in the house for this purpose.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)

Dear Doctor: I've had psoriasis for close to seven years, and lately it has been flaring up more often. Is there anything I can do with my diet to control this, or even prevent it from happening?

Dear Reader: That's a good question. Thanks to the growing body of research detailing the link between inflammation and chronic disease, there are some equally intriguing answers. To explore it further, let's start with what psoriasis is.

When you have psoriasis, your immune system has gone a bit haywire. It's sending faulty danger signals that cause skin cells to grow at 10 times their normal rate. That's much faster than your body can process and shed them, and the result is raised and itchy patches of red skin, often covered with silvery scales. Typically, these appear on the knees, elbows and scalp, but may also be present on the palms of the hands, soles of the feet and along the torso.

Although there is a complex genetic component to psoriasis, environmental factors are also at play. Stress, infection, certain medications, smoking and alcohol use have all been shown to be potential triggers for flare-ups.

The results of that research we mentioned make it increasingly clear that inflammation is a factor in many chronic and degenerative diseases, including heart disease, diabetes and many cancers. Since inflammation plays a significant role in psoriasis, a lot of attention is now being paid to your question of whether diet may affect the disease.

Due to the way psoriasis behaves, drawing conclusions can be difficult. Flare-ups are followed by periods of dormancy, which give way again to subsequent flare-ups. Since the nature of the disease is to fluctuate, connecting the dots between a specific dietary or behavioral change, and the absence or presence of flare-ups, is a challenge.

Still, scientists are beginning to find answers. In studies of psoriasis patients whose diets included fish oil supplements to add omega-3 polyunsaturated fatty acids, a measurable number of participants reported fewer and less severe flare-ups. When they stopped following the diet, the benefits also waned.

Gluten sensitivity may also play a role. In a study of individuals with antibodies to gliadin, one of the proteins that are present in wheat, following a gluten-free diet lessened psoriasis symptoms. When gluten was reintroduced to the diet, flare-ups became more frequent.

If you're interested in modifying your own diet, the National Psoriasis Foundation offers some guidelines. Foods to add to your diet include leafy green vegetables and colorful fruits such as spinach, kale, broccoli, squash and blueberries. Foods that are a natural source of omega-3 fatty oils are also on the list. They include cold-water fish, olive oil, walnuts and pumpkin seeds.

The foundation recommends that people with psoriasis avoid processed foods, refined sugar and fatty red meat. Research shows that maintaining a healthy weight is important as well.

The idea is that when you have an inflammatory disease, steering clear of foods with inflammatory effects can help. Whatever the outcome, the result is a more healthful diet.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095.)