Why do children cough?

Here’s another excerpt from my new book, How Your Child Heals. It’s from the chapter on symptoms, and it’s about what causes cough.

The hallmark of most respiratory illness, both in children and in adults, is a cough. Coughing is a reflex, one difficult to suppress. You probably know this from the experience of sitting in a quiet setting, such as in a lecture audience or in church, when you have a cold. The urge to cough is nearly impossible to deny, even with intense effort.

The upper and middle portions of the airway, meaning the space between the back of the throat, through the vocal cords, and down to the first branching of the windpipe, are thickly sown with sensors. They are particularly abundant right around the vocal cords and down at the area of the first branching of the windpipe into smaller breathing tubes. If anything touches these sensors the response is a cough. The reason this reflex is so powerful is that nature is fanatic about protecting our airways. We need to breathe every minute, and objects that might block our airways are potentially very dangerous. Since the last line of defense for the lungs is at the windpipe’s first branching, it makes sense that touching that spot provokes a particularly explosive episode of coughing.

Infections of the upper respiratory tract cause the mucous-secreting cells that line the walls to make more mucous, sometimes large amounts of it, and this extra material trips the cough sensors. The upshot is that we cough and cough until the mucus is cleared out of the airway via a mechanism doctors term a productive cough, meaning it produces sputum.

Often, however, a cough is dry–it does not produce any sputum at all because the cause for it is not excess mucous. We term this a nonproductive cough. It often comes in spasms of multiple coughs in succession, followed by a period of relative quiet. This kind of cough is caused by inflammation of the walls of the airway, something respiratory viruses do, and the inflammation triggers the cough sensors. In children, asthma is another common cause because asthma inflames the airways. A nonproductive cough can also happen if we inhale anything that irritates our airways, such as dust, smoke, or a noxious gas.

If a cough is from asthma, we have several medicines to treat that, such as inhaled albuterol. If it’s not asthma, specific treatment is more difficult. There are dozens of products sold over-the-counter as remedies for cough. None of them do much to help it, although they may soothe the back of the throat. The things many of them contain cause unwanted side effects in small children, so most doctors recommend not using them, as does the American Academy of Pediatrics. The last thing we want in a medication for children is something that does not help the situation and may actually cause harm.

We have medicines that really do suppress cough. They do not work on the airway; rather, they work on the brain itself to suppress the cough reflex. Codeine, a narcotic, is the one most commonly used, but there are others. We rarely use these medicines in children, especially small children, because they have significant side effects, primarily drowsiness and altered mental state. Additionally, if a cough is being caused by excess mucous or other material in the airway, we can make the situation worse by blocking the child’s ability to clear the stuff out.