Dear Mr/Mrs Pandey,
It is difficult to diagnose asthma in little children as pulmonary function tests are difficult to perform by children and therefore the diagnosis is usually retrospective based on response to treatment.
Chronic noctunal (night time) cough, audible wheeze after playing or exertion are symptoms suggestive of asthma and inhaled salbutamol can be tried to see the response.
Occasionally asthma is triggered by viral infections, so a temporary use of inhaled bronchodilators is a good treatment. Children may develop asthma after repeated viral infections and more so if they have allergies, like food allergy or rhinitis for example. And also, children may not develop asthma but a temporary relief with inhalers will provide comfort to the child in lowering lung inflammation and constriction.
Thanks.

Hi
Thanks for your query
See to diagnose asthma in a 1.5 year old is in fact very difficult because they cannot perform spirometry or any other bronchial challange test cannot be done in them. So as a physician we have to rely on clinical examination and history.
Among histories if there is family history of asthma, atopy or eczema then there is high chance the child developing asthma. Maternal smoking is also an important factor.
Among the examination, wheezing, rhonchi are important.
There are wheezing illnesses in childhood and if there are recurrence and persistence inspite of adequate treatment then these actually may be the initial manifestation of asthma.
As your physician have told you that your baby has asthma, i think, he has considered these facts before saying this. So please go with your doctor and take medications prescribed by him.
Thank you.