The Impact of the Pandemic on Cat and Dog Allergies

The impact of the COVID-19 pandemic on allergic patients is not clearly understood. The aim of this study is to investigate the changes in sensitivity to cat and dog allergens in patients with respiratory allergies in Istanbul during the COVID-19 pandemic.

Before the pandemic (March 2018 - March 2020) and during and after the pandemic (March 2020 - March 2022), a total of 5499 patients who underwent skin testing were retrospectively evaluated. The patients' age, gender, diagnosis, total IgE, and eosinophil values were recorded. Patients were divided into two groups: 2-6 years old and 7 years and older. The frequency of sensitization to cats and dogs was investigated in both groups before and after the pandemic.

The median age of the 5499 children included in the study was 77 months, with a range of 2 to 221 months. Furthermore, 55.7% of the children were male. Of the children, 59.1% were examined before the pandemic, and 40.9% during and after the pandemic. During the examinations, allergic rhinitis was identified in 1628 children (29.6%), asthma in 1829 children (33.3%), and both asthma and allergic rhinitis in 2042 children (37.1%). Allergies to cats were found in 247 children (4.5%), and to dogs in 166 children (3.0%). When comparing the age groups, the frequency of cat allergy in the 7-years and older group was found to have decreased compared to the pre-pandemic period, and the statistical difference was close to significance (p=0.08). However, regarding dog allergy, in the 7 years and older group, the sensitivity to dogs, which was 5.6% before the pandemic, had decreased to 2.6% during the pandemic, and this decrease was found to be statistically highly significant (p<0.001).

Environmental allergen exposure has a significant impact on the phenotype of allergic diseases. Changes in patients' lifestyles and increased time spent at home during the pandemic may have led to a decrease in contact with outdoor cat and dog allergens, resulting in a reduced frequency of cat and dog sensitivity. Additionally, the introduction of mask-distance-handwashing/disinfection rules during the pandemic is believed to have reduced contact with cat and dog allergens, potentially contributing to a decrease in allergy frequency.