I’m afraid I don’t know but presumably using cleaning products that come from more natural sources and ensuring air is filtered and that surfaces are dust free. Depends on the allergy I suppose.
Constantly cleaning your fans and windowsills will help stop the spread of dander/dust as it comes in. Wash anything placed in front of doors and windows as often as possible. Dust everything frequently and use a polisher/allergen prevention spray to coat the surface. If needed, take as much allergy medication before hand and wear a mask and goggles along with long sleeves and gloves if allergies are severe.