a cough in a healthy 4 year old can be many things. most commonly colds from viral infections can cause coughs. other causes can be allergies post nasal drip and asthma. if your child has had the cough for several weeks it is important to speak to your doctor. if he has allergies or asthma that is causing this there are medications available to make him feel better. call your doctor.
my 4 year old has been coughing only in the late evening during the night and until mid-morning for many weeks now. . i usually give him 1 to 2 l'il critters gummy vites that have echinacea vitamin c and zinc in them every day. he doesn't cough during the day. he had a cold a few weeks ago which has since gone away except for this cough. it actually starts late in the evening right around bedtime continues off and on during the night when he changes positions and then starts to go away around mid-morning. . . i would say it's probably more of a dry hacking cough. could it be whooping cough?