It has been reported that the incidence of allergic rhinitis (AR) is as high as 24.1% in adults and 16.8% in children in China. A study explored the changes in the incidence of AR in China, and the study showed that the incidence of AR in many cities in China increased significantly from 2005 to 2011. The latest Chinese guidelines for the diagnosis and treatment of allergic rhinitis pointed out that AR is an independent risk factor for asthma, and 40% of AR patients can be complicated with asthma. CARRAD reported that in adult asthma patients who received skin prick test or serum specific IgE (sIgE) for allergens, The positive rates of at least one allergen were 65.4% and 75.4%, respectively. With the acceleration of urbanization and the improvement of people's economic level, more and more families keep pets. Pets can promote people's physical and mental health, but there are also more and more people who are allergic to pets. Some studies have shown that pets are the third major allergen of respiratory allergic diseases, next to dust mites and pollen. Cats are by far one of the most popular pets, but in recent years, the prevalence of cat allergen has gradually increased. Animal allergens are present in saliva, urine, and dander, and they spread into the environment by adhering to the hair and dander of the animals, such that even in homes without pets, the level of allergens in the environment is sufficient to sensitize people. However, at present, the microbial impact of the microorganisms carried by pet cats on their owners and the living environment is unknown.

Inclusion Criteria:

• Adult patients (18-65 years).
• Patients with moderate to severe dust mite allergic rhinitis were diagnosed based on clinical history and positive cat allergen sensitization tests (skin prick test and/or specific IgE).
• Patients who visited the Department of Otolaryngology of the First Affiliated Hospital of Nanjing Medical University.

Exclusion Criteria:

• Patients who refused to accept specimen and questionnaire collection.
• Patients who had nasal diseases other than allergic rhinitis, such as nasal papilloma and nasal malignant tumor.

Patients diagnosed with cat-allergic rhinitis in the Department of Otolaryngology of the First Affiliated Hospital of Nanjing Medical University.