Dear Dr. Theriot: My daughter is 8 years old. She has been coughing for the past two weeks, but it doesn't seem bad enough to take her to the doctor. A friend of ours is a physician, and he told me that my daughter might have asthma. He said she might need asthma medicine. She has never wheezed in her life. I thought that asthma WAS wheezing. Help!!
Your question is timely as this time of year brings forth a plethora of respiratory infections and flare-ups of asthma. Generally speaking, your doctor friend might very well be correct. It is however, impossible to answer your question without much more information.
When you think of the respiratory tract, picture an upside down tree that starts with a large trunk (or windpipe) that keeps branching and getting smaller and smaller until it ends in the tiniest of twigs (small bronchioles). The medium sized bronchioles are tubes that have an inner lining of muscle that can constrict and get smaller, or relax and get larger. When you need more air, the bronchioles will dilate, or open up as a result of the relaxation of the muscle, and this lets more air in.
In asthma, two things occur at the level of the medium and smaller bronchioles. First, there is a spasm or constricting of the muscles which causes a narrowing of the tube. And secondly, there is an increased production of mucus which further narrows the opening of the bronchiole. When this happens, a person can get air into the lungs, but it is difficult to get the air out. The air actually gets trapped in the lungs causing the lungs to overinflate. So an asthmatic has to forcibly exhale to get each breath out. Because of the narrowing of the bronchiole, you hear the wheeze as the air passes through the narrowed opening.
Asthma medications, or bronchodilators, work by causing the muscles of the bronchioles to relax and open up.
A person doesn't have to wheeze to have asthma. Asthma can represent a whole spectrum from very mild, to very severe. In some cases there is mild spasm of the muscle and little mucus production. There might not be enough spasm to actually cause wheezing. But there is enough to cause the bronchioles to be "irritated", and this is what causes the persistent and nagging cough. In most cases the asthma medications do relieve the spasm and make the cough go away. This is probably what your doctor friend was referring to.
It must be stressed that there are many conditions that can cause very similar symptoms. These include a pneumonia, bronchitis, chronic post nasal drip from allergies or a sinus infection, or a tic/habit type cough. Each of these must be dealt with on an individual basis and are treated very differently.
Your daughter, like anyone with a chronic cough, should see their doctor and be evaluated to find out the exact cause of the cough. Only then can a treatment be started. I hope this answers your question.