Analysis of characteristics of Chenopodiaceae pollen induced seasonal allergic rhinitis in the Inner Mongolian grassland region of China

Objective: To analyze the clinical characteristics of Chenopodiaceae pollen induced seasonal allergic rhinitis (SAR) as well as the distribution and sensitization characteristics of Chenopodiaceae pollen in Inner Mongolia grassland of northern China. Methods: From May 2015 to August 2015, using stratified, cluster and random sampling, a field interviewer-administered survey study and skin prick test (SPT) were conducted in six areas of Inner Mongolia grassland (Xilinhot, Erenhot, Duolun, Tongliao, Jarud, Kailu), and pollen monitoring was carried out in the above six areas from January 1 to December 31 of 2015. The clinical characteristics of Chenopodiaceae pollen induced SAR, distribution and sensitization characteristics of Chenopodiaceae pollen in these regions were observed. SAS software 9.4 was used for data processing. Results: A total of 6 043 subjects completed the study. The prevalence of Chenopodiaceae pollen induced SAR was 13.2% (795/6 043). The highest prevalence was found in the 18-39 age group. Subjects from urban areas showed higher prevalence of SAR than rural areas (61.2% vs 37.9%, P<0.001). There was significant regional difference in the prevalence rate of Chenopodiaceae pollen induced SAR among the above six areas (Xilinhot 21.5%, Erenhot 17.8%, Duolun 8.9%, Tongliao 6.9%, Jarud 15.3%, Kailu 9.7%, P<0.001). The main clinical symptoms of Chenopodiaceae pollen induced SAR were sneezing (96.5%) and nasal itching (92.2%). Eye itching was more obvious among the ocular symptoms (69.1%), while fatigue (32.1%) and drowsiness (31.5%) were more prominent among other related symptoms. Among comorbidities of Chenopodiaceae pollen induced SAR, allergic conjunctivitis accounted for 71.4% (568/795), food allergy accounted for 86.7% (689/795) and asthma accounted for 16.7% (133/795). The peak of Chenopodiaceae pollen spread was in August. The prevalence of Chenopodiaceae pollen induced SAR was positively correlated with the concentration of Chenopodiaceae pollen (R2=0.78, P=0.043). The SPT positive rate of Chenopodiaceae pollen was 21.2% (1 282/6 043), and Xilinhot had the highest rate in six regions (28.0%, 236/842). Conclusions: The prevalence of Chenopodiaceae pollen induced SAR in Inner Mongolia grassland stays at a high level. Sneezing is the most obvious symptom of SAR. The peak of Chenopodiaceae pollen spread is in August and the prevalence of Chenopodiaceae pollen induced SAR is positively correlated with the pollen concentration.