Pediatric chronic cough: Allergies, environmental factors, and asthma-associated inflammation.

Background: Chronic cough (CC) is a common respiratory symptom in children, often linked to allergic conditions, environmental exposures, and potentially indicative of underlying asthma.

Objective: To investigate the relationships of CC in children with allergic predispositions, environmental exposures, and airway inflammatory markers.

Methods: A case-control study was conducted at a tertiary hospital. Data on cough duration, personal and family allergic histories, and environmental exposures were collected. Airway inflammation was assessed using fractional exhaled nitric oxide (FeNO₅₀), and lung function was evaluated via spirometry.

Results: Children with CC showed a higher prevalence of allergic conditions, including rhinitis (74.77% vs. 24.13%, OR = 9.312, p < 0.0001), food allergy (59.81% vs. 27.59%, OR = 3.907, p = 0.0017), eczema (55.14% vs. 31.03%, OR = 2.731, p = 0.0213), and family history of allergies (71.96% vs. 27.59%, OR = 6.738, p < 0.001). Environmental exposures, such as household smoking (55.14% vs. 20.69%, OR = 4.712, p = 0.001) and mold exposure (28.68% vs. 7.35%, OR = 3.442, p = 0.0251), were more common in the CC group. CC children exhibited elevated FeNO₅₀ (median: 18 vs. 14 ppb, p = 0.0153) and impaired small airway function (FEF75%pred: 53.84 ± 20.21 vs. 65.07 ± 28.52, p = 0.0170).

Conclusions: Pediatric CC is strongly associated with allergic predispositions, environmental exposures, and eosinophilic airway inflammation, potentially reflecting an asthma-related phenotype.