Hello dear! i can understand your concern. Your history suggests your child has hyper reactive airway disease. I would like to know a detailed history regarding family history of asthma and allergies. I would recommend a detailed physical examination by a pediatrician. I would advise you to start some good anti histamines like syp. levocetrizine 3 ml at night for 2 weeks and monteleukast sachet 4 mg at night for 3 months. To soothe the cough,ivy leaves extract containing syp.,comes with the name of no cough, prospan or coferb are also beneficial if giving twice or thrice daily for a week. You can also try some home remedies like 1 teaspoon of honey in a glass of luke warm water given once daily and also some soothing herbal tips like freshly squeezed ginger(few drops of juice of freshly ground ginger) in a table spoon of honey ,mix it with a pinch of black pepper powder. Give 2-3 drops of this mixture whenever he coughs.Steam inhalation twice daily especially before bed time is also very beneficial. Hope it will help. Wishing your child good health :-)