Supplementary Material for: Trends and clinical features of pet sensitization of allergic rhinitis from 2017- 2023 in Beijing, China

Introduction: Cats and dogs, as most common domestic pets, is an important source of indoor airborne allergens that can cause allergic rhinitis (AR) and other allergic diseases. This study aimed to determine the trends of sensitization of pets in recent years and disease severity in AR patients sensitized to pet’s allergens. Methods: This was a retrospective study, which examined 47,553 patients who were first diagnosed AR at the Department of Allergy of Beijing Tongren Hospital from January 2017 to December 2023. Clinical characteristics and disease severity of the patients were assessed based on the sensitization to allergen test. Results: This study found pets are the second most common indoor allergen in AR patients, with cat (26.6%) and dog (13.7%). The trend of sensitization to cats and dogs has shown a yearly increase from 2017-2023, and children and adolescent are the most susceptible to pet sensitization. Compared to other indoor allergens, sensitize to cat showed significant severe allergic symptoms, including nasal congestion, runny nose, and itchy eyes. The risk of asthma was increased by sensitization of Cat (P<0.001, OR=1.737) and dog (P<0.001, OR=1.659) Conclusion: Cats and dogs are important and common indoor allergens in AR, especially in children and adolescents, which have gradually increased over the past 7 years. Cat sensitization may lead to more severe AR symptoms and increase the risk of comorbid asthma.