My 5 year old son has displayed absolutely NO other symptoms (no runny nose, no cold, no fever, no loss of appetite, no loss of sleep, no sneezing, no "allergy mask", no previous allergies to anything -- food or airborne, no symptoms of allergies.
He simply woke up with a heavy cough. He doesn't have tightness in his chest, has not complained of shortness of breath (as he plays 1 hour of basketball), sleeps fine, etc.
He coughs and it is a deep rattle in his chest that produces phlegm -- but it's all clear. This has been going on for 3 days.