Why does my child cough?

Q: My 2-year-old son suddenly began coughing four weeks ago, with no other signs of being ill. No one else has been sick in our household. What could this be?

A: The most common reasons for children's coughs are viruses and asthma, which would likely also have symptoms like choking or wheezing, fever, or cold-like symptoms. Anytime a cough lasts more than 10 days or seems to be getting worse, you should call the pediatrician. It's also possible your son breathed a bit of food or some other object into his windpipe, known as aspiration. This can happen without your knowing it and may not get better on its own. It's worth considering if his cough started suddenly, if there weren't other signs of illness at first, and if he seems happy between coughing spells -- and, of course, if anyone remembers him eating suspect foods. Peanuts, popcorn, and bits of hard foods like carrots are especially prone to being aspirated, which is why you should not give these otherwise nutritious foods to children under 4 years old. Aspiration can eventually lead to pneumonia, which would cause your child to develop a fever, be short of breath, and start to look and act sick. Often an x-ray will show the cause, but sometimes a child will need a bronchoscopy, in which a tube is passed down the windpipe to look around and, if necessary, clean something out.

Originally published in Child magazine, 2007. Updated 2009