How can you distinguish dry cough from cough, associated with secretions in children of age 3?

ACUTE BRONCHITIS: Dry cough is easily distinguish from the productive cough by the sound and no phelm associated with it. Although 3 years old do not know how to spit, you can tell the difference.

Different sound.: The best way to learn the difference is for someone to tell you what kind of a cough you are listening to right now. I usually do this on visits with complaint of cough.