Multicenter study of seasonal and regional airborne allergens in Chinese preschoolers with allergic rhinitis

Abstract

This study is nationwide multicenter epidemiological research, aimed at investigating the distribution changes and seasonal patterns of various airborne allergens among preschool children with allergic rhinitis (AR) in different regions of China, and analyzing the clinical correlation between sensitization to various airborne allergens and AR symptoms in children. Information on children was collected through standard questionnaires, and total IgE (tIgE) and specific IgE (sIgE) for 11 inhalant allergens were tested. The results showed that dust mites are the primary allergens for preschool AR children (39%). Among pollen allergens, Amb a had the highest positivity rate (8.1%), followed by Art v (7.8%). The sensitization rates for two mites peaked in May (46.9% and 40.6%). Art v peaked in August (21.5%), while Amb a had peaks in May (12.7%) and August (17.8%). The sensitization peaks for various tree pollens mainly occurred in August. In the Eastern monsoon region, the sensitization rate to mites was significantly higher than in the Northwest arid and semi-arid regions; whereas, for pollen allergens, the sensitization rates to Amb a, Pla a, Pin a, Pop d, and Bet v were significantly higher in the Northwest arid and semi-arid regions than in the Eastern monsoon region. The correlation among various tree pollens, specifically between Pla a, Pin r, Pop d, and Bet v was strong (0.63 ~ 0.79), with a cross-overlapping percentage of 53.9%. Children with multiple pollen sensitizations had higher cumulative nasal symptom scores than those negative for pollen (P < 0.01). Children with only pollen sensitization had higher cumulative rhinitis symptom scores than the all-negative group (P < 0.0001) and the mite-only sensitization group [P < 0.05], while the mite-only sensitization group also had higher scores than the all-negative group [P < 0.05], and the group sensitized to both pollen and mites had lower scores than the pollen-only group [P < 0.05]. This study indicates that sensitization to mites and grass pollens exhibits significant regional differences, with grass pollen allergies primarily occurring in autumn, sensitization to pollens in general exhibits a pronounced seasonal pattern. Moreover, pollen sensitization aggravates nasal and ocular symptoms in AR children.

Keywords: Allergic rhinitis; Epidemiology; House dust mite; Pollen; Preschool; Regional differences.

Figure 1

Sensitization rates of mite and pollen allergens in children with rhinitis, showing (A) overall sensitization rates, and differences in sensitization rates by (B) gender, (C) different rhinitis comorbidity groups, and (D) different months."

Figure 2

Radar map of the regional distribution of sensitization to (A) mites, (B) grass pollen and (C) tree pollen in children with rhinitis.

Figure 3

(A) Heatmap illustrating the correlation between mites and pollen, and (B) an Upset plot reflecting the cross-overlapping of Pla a, Pin r, Pop d, and Bet v.

Figure 4

(A) Scores for individual nasal symptoms in children with AR, (B) the differences in cumulative nasal symptom scores among different rhinitis comorbidity groups, (C) the differences in cumulative nasal symptom scores among different mite sensitization groups, and (D) the differences in cumulative nasal symptom scores among different pollen sensitization groups. The cumulative nasal symptom score refers to the total score obtained when the severity of nasal congestion, itchiness, runny and sneezing is reported as no symptoms (0 points), mild (1 point), moderate (2 points), or severe (3 points).AR: Allergic rhinitis, AR&AS: Allergic rhinitis combined with asthma, AR&AD: Allergic rhinitis combined with dermatitis. **: P < 0.01, *****: P < 0.0001, ns: no significance.

Figure 5

Comparison of mite- and pollen-allergic children with rhinitis for (A) differences in nasal symptoms, (B) differences in tIgE levels, and (C) differences in the positivity rate for all allergens. *: P < 0.05, **: P < 0.01, **: P < 0.0001, ns: no significance.