There are many components in dust people can be allergic to including dust mites, pet dander and pollen. All of these things can be in your also exist in your clothes. Try doing your laundry in hot water to denature some of the causitive proteins and cleaning your place really well. Carpet can be really hard to clean and even if theres not animal there now, the allergens can still persist for several months. Also consider mold as a potential allergen.