Different Aspects of COVID-19: "Stay at Home" Increased Cat and Mite Sensitivity in Preschool Children.

Background: Indoor allergen exposure and senitization is expected to increase significantly during the COVID-19 pandemic. The aim of this study was to assess the impact of this altered allergen exposure on allergen sensitivity patterns in children with asthma.

Methods: Demographic data, clinical characteristics, and laboratory findings of asthmatic children aged 5 years and younger were assessed May 2019 to May 2020, 1 year after the start of lockdown measures. Those asthmatic children were compared with age- and sex-matched asthmatic peers assessed before the pandemic. Group I included asthmatic children who underwent skin testing within 12 months of the start of the lockdown (n = 112), while Group II included asthmatic children whose skin testing was done before the lockdown (n = 224).

Results: A total of 336 preschool children diagnosed with asthma were evaluated. House dust mite (HDM) and animal dander (cat, dog) senitization rates were significantly higher in Group I than in Group II (66.1% vs. 42.9%; OR: 2.5, 95% CI: 1.6-4.1, p < 0.001 and 8.0% vs. 1.3%; OR: 6.4, CI: 1.7-24.2, p = 0.006, respectively). However, the number of asthma attacks requiring systemic corticosteroid treatment was higher in Group I than in Group II (p = 0.001). The duration of lockdown emerged as a significant risk factor for HDM senitization (p < 0.001, OR: 2.6, 95% CI: 1.6-4.1) and animal allergen senitization (p = 0.006, OR: 6.4, 95% CI: 1.7-27.3).

Conclusion: During the pandemic, senitization to indoor allergens, including HDM and animal dander, increased significantly in asthmatic children. This may be attributed to changes in lifestyle, increased time spent indoors and increased pet ownership.