The differential impact of air pollutants on acute urticaria and chronic urticaria: a time series analysis.

Several studies have revealed a relationship between short-term exposure to air pollution and the exacerbation of certain skin conditions. This study was developed to expand on these findings by exploring the potential association between exposure to air pollutants including particulate matter, sulfur dioxide, and ozone and the incidence of acute and chronic urticaria in Shenyang, China, from 2016 to 2018. Exposure-response relationships between daily mean concentrations of these airborne pollutants and visits to outpatient dermatological clinics for acute urticaria and chronic urticaria were evaluated via a time series analysis approach using a generalized additive model. This analysis revealed that a 10 μg/m3 increase in daily mean O3_8h concentrations was associated with a 0.36% (95% CI, 0.31-0.41%), 0.35% (95% CI, 0.30-0.40%), and 0.34% (95% CI, 0.29-0.39%) increase in the number of outpatient visits for acute urticaria on that day (lag0), lagging day 1 (lag1), and lagging day 2 (lag2), respectively. O3 levels also had a similar but weaker effect on the frequency of patients seeking outpatient care for chronic urticaria. These analyses also revealed that estimated 0.47% (95% CI, 0.41-0.52%) and 0.46% (95% CI, 0.40-0.51%) increases in dermatological outpatient acute urticaria visits were observed for every 10μg/m3 rise in O3_8h concentrations on cumulative lagging days (lag01 and lag02). Increases in particulate matter (PM2.5, PM10) levels had a similar cumulative effect on patients with chronic urticaria. In summary, these results suggest that short-term O3, PM2.5, and PM10 exposure can increase the risk of acute urticaria and chronic urticaria.