To minimise my allergies, I do all the stuff mentioned above. Try to remove triggers as much as possible and treat symptoms. I don't vacuum myself and try not to dust. If I have to, I dust with a wet cloth. If I can go outside while DH vacuums, I do. I have just had a flare up with the change of season (pregnancy can also play a part) that gave me asthma and eczema as well as hayfever. Had to go back on my asthma preventer as well as my reliever meds. Much worse at night, which makes me think closing up the house and being indoors is a contributing factor (so more the dust and weather than pollens or plants).

I'm the opposite to Clover's DD in that the dry air makes me worse than humidity
So in that case you have to humidify the air, hanging of damp cloth in a room or wiping it on your face and body reintroduces moist so you won't be dehydrated..