It probably is an allergy/reaction to pollen or some other irritant in the air. It could also be that there is something in his diet that he is sensitive to - either gluten or dairy, because this could also cause chronic post nasal drip. Did you recently move to a new area or new house? I would actively search for anything that could be causing the post nasal drip (in the air or house) and if you cannot think of anything, then see if it could be coming from his diet. You can keep him on telfast, but one obviously does not want to keep a child on chronic medication if it is preventable. Good luck and I hope you find the answer soon.
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