Hello. Thank you for asking at HCM. There are many factors contributing to development of respiratory allergy in a child. Heredity, environment (pollution, humidity, temperature, etc), dietary habits, etc contribute to it. I guess your son has allergic rhinitis with childhood asthma. I would suggest you to consult an Allergist-Immunologist, who may suggest allergy testing after detailed history from you. Allergy testing will help to know type of asthma (allergic or non-allergic) and if it is allergic, identification of allergen causing the problems to your son. If indicated, he may suggest specific allergen immunotherapy to your son which works on immune system to treat the allergy. Regarding age of cure, it depends on type of asthma. Most childhood asthma improve by 6-7 years of age, but if a child is highly allergic, herediary and environmental factors are there, he may continue to have asthma later. I am surprised to know that your son is only 4 years old and he is able to use rotacaps. Generally older children only can use rotacaps appropriately. If technique of using rotacaps is not correct, the drug does not go into lungs in right amounts. So I would suggest you to show the technique of using rotacaps to any pediatrician/physician and if it is not correct, you may use Metered Dose Inhalers with Spacers for budecort. Personally I believe Inhaler with Spacer is best equipment for a 4 years child. Hope this will help you and solve your queries. Wish your son the best of the health. Regards.