D3.157 - Clinical characteristics and associated factors of persistent asthma in preschool children with wheezing in a tropical region

Recurrent wheezing in preschool children represents a heterogeneous clinical spectrum, and progression to persistent asthma remains difficult to predict. This study aimed to describe the clinical characteristics of preschool children with wheezing in a tropical region and to evaluate factors associated with persistent asthma at school age.

We conducted a retrospective cohort study including children younger than 6 years with wheezing, evaluated at the Allergy Unit of a tertiary referral hospital between 2017 and 2024. All patients underwent skin prick testing. The primary outcome was persistent asthma, defined by the presence of at least one of the following after 6 years of age: asthma-compatible symptoms, use of controller medication, airflow obstruction on spirometry or oscillometry, or severe events leading to hospitalization or intensive care unit admission. Associations were assessed using bivariate logistic regression, reporting odds ratios (OR) with 95% confidence intervals (95% CI).

A total of 612 patients were included, 326 (53.3%) were female, with a median age at first consultation of 2 years (IQR 1–3). Bronchiolitis was the most frequent prior condition, reported in 244 (39.9%), followed by a family history of allergic diseases in 179 (29.2%) and prematurity in 62 (10.1%). Rhinitis was reported in 426 patients (69.6%), followed by atopic dermatitis in 240 (39.2%) and food allergy in 64 (10.5%).

Among the 563 patients who underwent aeroallergen skin prick testing, sensitization was identified in 185 (32.9%), most commonly to Dermatophagoides pteronyssinus in 175 (31.1%). Among the 274 patients who underwent food skin prick testing, sensitization was identified in 41 (14.9%), most commonly to egg extract in 20 (7.3%). Oscillometry was performed in 133 (21.7%) patients, showing obstructive abnormalities in 70 (52.6%). The modified asthma predictive index was positive in 139 (22.7%).

Follow-up beyond 6 years was available for 129 patients (21.1%), with a median age at follow-up of 8 years (IQR 7–10), of whom 97 (75.2%) met criteria for persistent asthma. Blood eosinophilia ≥4% was the only factor significantly associated with the outcome (OR 2.46; 95% CI 1.06–5.71; p=0.043).

Despite limited follow-up beyond 6 years, blood eosinophilia ≥4% was the only associated factor with an increased risk of persistent asthma at school age. This suggests that early use of inflammatory biomarkers may improve prognostic stratification.