I was told when my son turn 7yo,doc can check whether he has asthma or not. he's 6, so right now only inhaler can help him.is that right?

Asthma: We usually don't wait till that age to check,history and physical examination suffice to diagnose,what you might be referring to is ability to use peak flow meter or perform spirometry to document bronchospasm and its reverisbility with treatment.If he truly has asthma,different kinds of medications can help, your best chance is to keep the follow up with your doctor/allergist, wish you wellness

No: I agree with Dr Hegab's note that one should not wait to make a diagnosis of asthma. The age 7 advice was likely based on some reports noting that the manifestation of asthma is likely fixed after age 7 years but not the treatment or diagnosis. I hope you will get him to an allergist soon given the history of peanut allergy, it is highly unlikely that his asthma will go away.