House dust, as well as cedar pollen, is an important antigen that causes nasal allergy. Various materials and species of mites are included in house dust; in particular, Dermatophagoides pteronyssinus and Dermatophagoides farinae are important causative antigens of asthma and nasal allergy. These mites proliferate in house dust when certain conditions such as temperature and humidity are satisfied and cause allergies in people. For the treatment of allergic rhinitis caused by house dust, it is important to remove the antigens and select the most appropriate treatment method according to the Practical Guidelines for the Management of Allergic Rhinitis in Japan.