On the basis of frequency and severity of symptoms asthma can be categorised. If frequency is less as in your case (last attack 3 months back) it is intermittent asthma. For management of intermittent asthma only salbutamol
inhalation is needed as and when required. The treatment prescribed for your child is according to moderate/ severe persistent asthma
Some antiallergic agents can also be used for treatment.
So I would suggest you to consult your doctor and discuss for the long and short term management and proper diagnosis of the condition.