DEAR DR. DONOHUE: I am 37 and have just been told I have asthma. I thought only kids got asthma. I was having trouble catching my breath and had coughing spells. After three misdiagnoses, I finally got the asthma one. I am doing better, but the sprays and medicines are bewildering. Can you give me an idea of what’s going on with me, my lungs and my medicines? – T.L.

ANSWER: Asthma does not discriminate when it comes to age. Adults as well as children get it. Close to 8 percent of people in Canada and the United States have it. Take 8 percent of 312 million people, the rough population total of these countries, and you have a staggering number of people.

Asthma targets the bronchi, the airways that bring oxygen into the lungs. Asthmatic airways are super-sensitive. They react to airborne irritants with a gusto that makes bringing fresh air into the lungs and ridding the lungs of stale air a serious challenge. The airways are constricted. They are also filled with thick mucus.

In addition to a struggle for air, coughing is common, particularly at nighttime and in the early morning.

Viral infections are an asthma trigger. The simple cold is an example. Cold, dry air can provoke asthma attacks. So can emotional stress and (hold on to your hats) heartburn.

Be thankful that the number of medicines, both in pill form and as sprays, leaves you overwhelmed. Today’s medicines keep most asthmatics breathing easily most of the time, something that was not possible only a few short years ago.

One class of medicines is used to abort an asthma attack. Proventil and Ventolin are examples. Another class of medicines is used to prevent attacks from happening. For example, sprays with cortisone drugs are often used on a daily basis. Vanceril, AeroBid, Azmacort and Flovent are such cortisone sprays.

A brand-new medicine, Xolair, is available for people who don’t respond to the older, standard drugs. It’s given by an injection.

The entire asthma story is told in the pamphlet by that name. Readers wishing a copy can obtain one by writing: Dr. Donohue – No. 602, 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 notice some blood in my seminal fluid. I have no pain. I am 35 and healthy in all respects. Could this be a sign of cancer? – R.K.

ANSWER: It is hazardous to say “never” when it comes to medical matters, but the chances that blood in the seminal fluid indicates cancer are as close to never as anything can be.

The blood usually comes from a leak in one of the tiny blood vessels that supply the tubules through which sperm passes.

Quite often, men on blood thinners such as Coumadin or men who take daily aspirin have blood in their seminal fluid because their blood is thin. Inflammation of the prostate gland is another source for such blood.

All you need do is mention this to your doctor. Without an exhaustive search, the doctor can give you assurance that the blood in your fluid is not due to anything sinister.

DEAR DR. DONOHUE: I need you to tell me what a “left anterior hemiblock” is. I have a copy of a recent ECG I had done, and it says I have this. Should I get the opinion of a cardiologist? – R.K.

ANSWER: A left anterior hemiblock is a common finding on an ECG. Usually it has no serious implications.

The electric signal created by the heart’s pacemaker makes its way to the two lower heart chambers, the ventricles, by way of cables called the right and left bundles. The left bundle divides into two smaller bundles, the left anterior and left posterior bundles. You have a short-circuit in your left anterior bundle. The electric signal still reaches your left ventricle, but it has to take a detour.

Check with your doctor. You don’t need a cardiologist unless your primary doctor says so.

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.