Abstract

Objective:

To analyze the prevalence and distribution patterns of aeroallergens in children with respiratory allergic diseases in Sichuan Province based on skin prick test (SPT) results.

Methods:

This retrospective cross-sectional study included 7,301 pediatric patients with respiratory allergic diseases who attended the outpatient department of West China Second University Hospital between January 2023 and December 2024. All patients underwent standardized skin prick testing.

Results:

Overall, 52.4% of children showed positive SPT results. The three most prevalent sensitizing allergens were Dermatophagoides pteronyssinus (Der.p), Dermatophagoides farinae (Der.f), and house dust. Among the 3,826 children with positive SPT results, 86.5% were sensitized to two or more allergens. Most allergens exhibited the highest positive rates in the Sichuan Basin. With increasing age, sensitization rates to most inhalant allergens showed an upward trend. Across all age groups and disease categories, Der.f, Der.p, and house dust remained the most frequently detected allergens. Preschool children had the lowest overall SPT positivity rates. In addition, children with allergic rhinitis and those with concomitant atopic diseases showed significantly higher sensitization rates and broader polysensitization profiles than children with asthma alone or without such comorbidities.

Conclusion:

Der.p and Der.f are the predominant airborne allergens among children with respiratory allergic diseases in Sichuan Province, likely influenced by the region's humid basin climate and geographic heterogeneity. Sensitization patterns vary significantly according to age, disease phenotype, geographic region, season, and the presence of concomitant atopic diseases. These findings provide important region-specific evidence for optimized allergen screening, early risk stratification, and individualized immunotherapy strategies in pediatric clinical practice.

Key message

This large-scale retrospective study of 7,301 children with respiratory allergic diseases in Sichuan Province revealed that Dermatophagoides pteronyssinus and Dermatophagoides farinae were the predominant aeroallergens, followed by house dust. The majority of sensitized children exhibited multiple allergen sensitization, and the overall positive rates increased with age. Importantly, children with other atopic diseases showed higher sensitization rates to major aeroallergens, suggesting that comorbid atopic conditions may be associated with enhanced allergic sensitization and represent a higher-risk subgroup for progressive allergic disease. These findings emphasize the regional dominance of mite sensitization and the influence of local climate, geography, and patient-related factors on pediatric allergic disease patterns, while also providing region-specific evidence for optimized allergen screening and individualized immunotherapy strategies.

1 Introduction

Allergic diseases encompass a group of immune-mediated hypersensitivity disorders elicited upon exposure to specific allergens via contact, ingestion, or inhalation (1). These conditions can affect multiple organ systems, with the respiratory tract, skin, and gastrointestinal tract being the most frequently involved. In addition to substantially compromising quality of life, allergic diseases impose significant economic burdens on both families and healthcare systems and, in severe instances, can be life-threatening (2). Due to their chronic nature and high recurrence rate, they pose a substantial and escalating challenge to global public health.

Respiratory allergies represent the most common form of allergic disorders, with allergic rhinitis (AR) and asthma (AS) being the two predominant manifestations, especially in pediatric populations. Epidemiological studies indicate that the global prevalence of AR in children is approaching 40% (3). In China, the prevalence of AR among children reached 18.46% in 2021 and continues to exhibit a steady increase (4). According to the Global Burden of Disease (GBD) database, around 97.5 million children worldwide were affected by asthma in 2021, including 9.4 million cases in China (5). The prevalence of asthma among children in major Chinese urban areas has also risen significantly, with cumulative incidence increasing from 1.09% to 3.02% over the past three decades. Repeated nationwide surveys consistently corroborate this upward trend in childhood asthma (6–8). Furthermore, AR and AS are closely interrelated: AR is widely recognized as a significant risk factor for the development of AS, and epidemiological data reveal substantial comorbidity between the two conditions. It is estimated that approximately 30% of patients with rhinitis eventually progress to asthma, while up to 80% of those with persistent asthma also present with rhinitis (9).

Allergens, also known as antigens, act as both pathogenic factors and triggers in respiratory allergic diseases, and sensitization to inhaled allergens is a key determinant of the development of airway disorders (10, 11). Upon re-exposure to sensitizing allergens, inflammatory mediators such as histamine are released, initiating a cascade of allergic responses that include bronchospasm and mucosal edema (12). Extensive research has demonstrated that sensitization profiles exhibit considerable geographic, climatic, and seasonal variation, reflecting the extensive diversity of inhalant allergens (13–15).

China encompasses a vast geographical area with extensive latitudinal coverage, complex topography, and marked climatic variations across regions. Although several nationwide surveys have reported allergen sensitization patterns in China, region-specific data focusing on pediatric respiratory allergic diseases remain limited. However, updated data on sensitization patterns to inhalant allergens among the pediatric population in Sichuan Province remain scarce. In particular, the complex climatic and topographical characteristics of Sichuan Province may lead to distinct aeroallergen exposure patterns that differ from those reported in other regions. The skin prick test (SPT), a standard diagnostic procedure for detecting specific IgE-mediated sensitization, provides a rapid and reliable method for allergen screening (16). It is especially useful in patients with allergic rhinitis and asthma for identifying causative allergens, thus supporting the development of personalized avoidance strategies and guiding specific immunotherapy.

Therefore, this study aims to investigate the prevalence and sensitization profiles of inhalant allergens among children in Sichuan province by employing a large-scale SPT. It further seeks to analyze variations in sensitization across demographic characteristics, allergic disease subtypes, and geographical and climatic factors, thereby providing a scientific basis for the early prevention and management of pediatric respiratory allergic diseases in the region.

2 Methods2.1 Study participants

This retrospective cross-sectional study enrolled pediatric patients with respiratory conditions who attended the outpatient department of West China Second University Hospital between January 2023 and December 2024.

The inclusion criteria were as follows: (1) diagnosis of allergic rhinitis (AR) or asthma, established according to the Chinese Guideline for Diagnosis and Treatment of Allergic Rhinitis and the Guideline for the Diagnosis and Optimal Management of Asthma in Children (2016), respectively; (2) age between 0 and 18 years, with skin prick testing performed; and (3) availability of complete medical records, including age, sex, home address, diagnosis, clinical history, and SPT results.

Patients were excluded if they met any of the following criteria: (1) severe dysfunction of major organs (e.g., heart, liver, or kidneys); (2) autoimmune diseases or immunodeficiency disorders; (3) immune dysfunction resulting from prolonged use of corticosteroids or immunosuppressants; or (4) discontinuation of oral antihistamines or topical corticosteroids for less than one week prior to testing.

Children diagnosed with isolated non-respiratory allergic conditions (e.g., food allergy or atopic dermatitis without concomitant AR or asthma) were excluded from the main analyses.

2.2 Data collection

Eligible cases were identified from the electronic medical record system. Relevant patient information was extracted, and a structured database was constructed following a process of dual-entry verification, collation, and integration. All data were recoded to ensure anonymity, completeness, and accuracy.

Patients were categorized into three age groups according to commonly accepted pediatric developmental stages, as described in Nelson Textbook of Pediatrics and supported by previous epidemiological studies on pediatric allergic diseases (17, 18). The age groups were defined as early childhood (0–6 years), school-aged children (7–12 years), and adolescents (13–18 years). Although four children were recorded as 0 years of age, all were older than 28 days and therefore were not neonatal cases. They were also classified by clinical diagnosis into the following groups: allergic rhinitis (AR), asthma (AS), and comorbid asthma with allergic rhinitis (AS + AR).

2.3 Geographic and climatic classification

According to the residential addresses recorded in the electronic medical records, participants were classified into three geographic-climatic regions based on the topographic and climatic characteristics of Sichuan Province: the Sichuan Basin, the mountainous regions of southern Sichuan, and the plateau areas of northern Sichuan. This classification was based on the regional geographic division commonly used in regional epidemiological and climatological studies in Sichuan Province.

2.4 Skin prick test

Skin prick testing was performed by a trained operator under the supervision of a respiratory physician, following a standardized protocol. The volar forearm was cleansed with 75% ethanol or normal saline and allowed to air-dry. Subsequently, a positive control (histamine), a negative control (saline), and a panel of allergen extracts were applied. A sterile lancet was held at a 90-degree angle to the skin and used to prick through each droplet with a quick, firm motion, maintaining contact for approximately one second to ensure epidermal penetration. A new, single-use lancet was employed for each allergen to prevent cross-contamination. Patients or their guardians were instructed to keep the forearm extended with the palm facing upward during a 15–20 min observation period. The skin index (SI) was calculated as the mean wheal diameter of the allergen divided by the mean wheal diameter of the histamine positive control. Sensitization levels were graded as follows: SI = 0 (negative); Level 1 (0 < SI < 0.5, “+”); Level 2 (0.5 ≤ SI < 1.0, “++”); Level 3 (1.0 ≤ SI < 2.0, “+++”); Level 4 (SI ≥ 2.0, “++++”). Reactions graded from “+” to “++++” were considered positive, and grades “+++” or “++++” were defined as strongly positive. The allergen panel comprised ten common inhalant allergens: Dermatophagoides farinae (Der.f), Dermatophagoides pteronyssinus (Der.p), Cat dander, Dog hair, Cockroach, Penicillium, Japanese hop, House dust, Artemisia, and Feather. Multiple sensitization was defined as a positive skin reaction to two or more distinct allergens.

2.5 Statistics

Statistical analyses were conducted using SPSS Statistics(version 27.0; IBM Corp). Categorical variables were expressed as numbers and percentages. Group comparisons for categorical data were performed using the Chi-square test, with Fisher's exact test applied when expected cell frequencies were below 5. The Bonferroni method was employed to adjust for multiple comparisons. Multivariable binary logistic regression analysis was conducted to identify factors associated with positive skin prick test (SPT) results, with odds ratios (ORs) and 95% confidence intervals (CIs) reported. Additional multivariable binary logistic regression analyses were performed to assess whether concomitant atopic diseases were independently associated with sensitization to major aeroallergens after adjustment for age and sex. A two-sided p-value of < 0.05 was defined as the threshold for statistical significance.

2.6 Ethical considerations

This study was approved by the Ethics Committee of West China Second University Hospital, Sichuan University (Approval No. 2025-IRB-249). The requirement for written informed consent was waived by the Ethics Committee due to the retrospective study design and the use of fully anonymized patient data. No additional ethics approval was required in accordance with local and national guidelines.

2.7 Data availability statement

The data that support the findings of this study are not publicly available due to privacy and ethical restrictions related to patient information. Anonymized datasets are available from the corresponding author upon reasonable request.

3 Results3.1 Participant characteristics

Between January 2023 and December 2024, a total of 7,301 patients (6.5 ± 2.9 years) were enrolled in this study. The cohort comprised 4,572 boys (62.6%, 6.6 ± 2.9 years) and 2,729 girls (37.4%, 6.3 ± 2.8 years). Based on clinical diagnosis, 5,475 patients (75.0%) were identified with allergic rhinitis (AR), 1,103 (15.1%) with asthma (AS), 723 (9.9%) with comorbid asthma and AR (AS and AR) (Table 1).

VariableNumber (n = 7,301)SPT-positive subjectsn%n%X2POverall SPT-positive cases3,82652.4Gender19.045<0.01# Male4,57262.62,48654.4 Female2,72937.41,34049.1Age(years)139.750<0.01# 0–64,13856.71,91946.4 7–122,93040.11,76160.1 13–182333.214662.7Disease1,404.752<0.01# Allergic rhinitis5,47575.03,52364.3 Asthma1,10315.1544.9 Asthma with allergic rhinitis7239.924934.4Region301.807<0.01# Sichuan Basin6,79593.13,74955.2 Mountainous regions of southern Sichuan3374.64814.2 Plateau areas of northern Sichuan1692.32917.2Season26.834<0.01# Spring1,58121.777749.1 Summer2,65136.31,46955.4 Autumn1,90726.11,02353.6 Winter1,16215.955747.9

Characteristics of participants.

Of the 7,301 participants, 3,826 (52.4%) showed a positive skin reaction to at least one allergen, as summarized in Table 1. The top three allergens with the highest proportions in both SPT sensitization rates and strong positive reactions were Der.p, Der.f, and house dust (Table 2). 518 (7.1%) cases were sensitized to one allergen, 3,308 (45.3%) cases were sensitized to 2 or more allergens (Figure 1A).

Allergen TypesSkin Prick TestPositive NumberStrong Positve Number−++++++++++N%N%Der.p3,9452471,0341,5914843,35646.02,07528.4Der.f3,9903631,0851,4763873,31145.31,86325.5House dust6,048404648189121,25317.22012.8Cat dander6,8131622388084886.7881.2Dog hair6,8341542179154676.4961.3Cockroach6,8811592144434205.8470.6Japanese hop6,907101137100563945.41562.1Artemisia7,097627851132042.8640.9Penicillium7,2233531102781.1120.2Feather7,254162650470.650.1

Positive rates and distribution of various allergens in skin prick test in patients.

Der.p, Dermatophagoides pteronyssinus, Der.f, Dermatophagoides farinae.

Sensitization to different number of positive allergens in different groups. (A) The number of people in different number of positive allergens in all person, (B) The number of positive allergens in different genders. (C) The number of positive allergens in different ages. (a) Compared between 0 and 6 years group and 7–12 years group. (b) Compared between 7 and 12 years group and 13–18 years group. (c) Compared between 0 and 6 years group and 13–18 years group. (D) The number of positive allergens in different diseases. (a) Compared between AR group and asthma group. (b) Compared between asthma group and AR combined with asthma group. c: Compared between AR group and AR combined with asthma group. *P < 0.05. #P < 0.01.

3.2 Differences in allergic sensitizations among different groups

Gender differences: The overall SPT positivity rate was significantly higher in boys (54.4%) than in girls (49.1%, P < 0.01) (Table 1). Boys also showed significantly higher sensitization rates to Der.p, Der.f, house dust, and Artemisia. In addition, male patients had a higher frequency of strongly positive reactions (grade “+++” or “++++”) to Der.p and Der.f compared to females. No significant gender differences were observed for the other six inhalant allergens (Table 3). Furthermore, boys exhibited a significantly higher proportion of polysensitization to three or more allergens than girls (P < 0.01) (Figure 1B).

ParametersDer.fDer.pHouse dustCat danderDog hairCockroachJapanese hopArtemisiaPenicilliumFeatherGender Male2,1362,1828233262982722631425326 %46.747.7187.16.55.95.83.11.20.6 Female1,1751,174430162169148131622521 %43.14315.85.96.25.44.82.30.90.8 P0.002#<0.01#0.015*0.0530.6210.3770.0870.04*0.3490.295Diseases AR3,0743,0891,1564394153883481806542 %56.156.421.18.07.67.16.43.31.20.8 AS384816121264352 %3.44.41.51.11.10.50.40.30.50.2 AR + AS19921981374026422183 %27.530.311.25.15.53.65.82.91.10.4P<0.01#<0.01#<0.01#<0.01#<0.01#<0.01#<0.01#<0.01#0.0960.061Geographic regions Basin3,2593,3041,2364754594123741857646 %4848.618.276.86.15.52.71.10.7 Mountain3536146568820