Suggest Remedy For Cough And Allergy In Child

hi there! i would like to ask about my child s asthma. he s been taking his seretide puff (2 puffs) twice a day for 5 days now and i nebulize him before bedtime but he is still coughing and seems the allergy is still there. his salbutamol syrup has been given to him for a week and he finished it yesterday. what seems to be the problem because there is no sign of relief? any meds for this? thanks.