 [ Symptoms ] when i am ready to increase the amount of weight i am lifting how much more weight should i add [ Disease ] 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 cough in children can have many reasons recurrent infections allergies asthma can be important ones please get your child thoroughly examined by expert paediatrician with few tests the cause of persistent bed time cough can be confirmed