Hidden bronchial obstruction in atopic dermatitis: just like wheezy infants

Objective Atopic dermatitis (AD) is frequently associated with respiratory comorbidities, yet data on pulmonary function in infancy remain scarce. This study aimed to evaluate pulmonary function in infants with AD using tidal breath analysis (TBA) and to compare these findings with those of wheezy infants and healthy controls (HC).Methods A total of 115 infants under three years of age were categorized into three groups: infants with AD without any respiratory disease or symptoms (n = 50), infants with wheezing (n = 35), and HCs (n = 30), and their data were retrospectively analyzed. Pulmonary function was assessed using TBA. Peak tidal expiratory flow time (TPTEF), time to expiratory time (TE), ratio of peak tidal expiratory flow time to expiratory time (TPTEF/TE), volume required for PTEF (VPTEF), expiratory volume (VE), and respiratory rate (RR) were measured by TBA. The key parameter was the TPTEF/TE. Wheezing phenotypes were classified as episodic viral wheeze (EVW) or multiple-trigger wheeze (MTW).Results Significant differences were observed among the three groups in terms of TPTEF (p = .022), TPTEF/TE (p < .001), VPTEF/VE (p < .001), and RR (p = .044). Subgroup analysis revealed that TPTEF/TE was significantly lower in both wheezing infants (p = .003) and those with AD (p < .001) compared to HC, with no significant difference between the wheezing and AD groups (p = .668). Additionally, TBA parameters did not significantly differ between the EVW and MTW phenotypes (p > .05).Conclusion Despite the absence of respiratory symptoms, TBA revealed bronchial obstruction in infants with AD, comparable to wheezy infants. Pulmonary function also showed no significant differences between wheezing phenotypes.