I previously also brought my baby to those normal PD at neighbourhood and in shopping mall, they are more to GP type of PD to me so I would suggest you send your son to PD that have a clinic in hospital and requested them to do a swab allergic test..
My baby did e swab (similarly like PCR as is same way of testing) after having prolonged coughing and phlegm, and glad that after test we get to know she was having lungs infection and given nebulizer as treatment..
Anonymous