Well I have asthma and suffer with hay fever and dust allergies - Ollie doesn't help but I can sail through some months outside of hay fever season with nothing then I will get itchy eyes sneezing etc.
Last couple of weeks my eyes have been dreadful and thought about buying drops, instead took tabs for a couple of days and back to normal. I have taken tabs on and off since I was about 15 and still take them as and when. I do get very stuffy nose at times and find that some allergy tabs dry you up
I would say that if your son doesn't have a history of allergies he could well settle down - if I get bad I have a really serious clean with Dyson plus hose etc and clean the hep filter before, through the window open, as I can tell when it dust rather than pollen. Also lots of washing hands might help with bacterial wash, the soft hairs off dogs can really stick at edge carpets and travel along wooden floor etc and go under things. A quick vacuum might not get these.
The worse I have ever been was with a friends long haired cat - not too bad with short haired although my eyes itch and have mild rash/hives if they lean on my arm.
Hope it settles
Julie