Allergic diseases and COVID-19: experience of a single Italian hospital during the first COVID-19 wave

The aim of this study was to compare the number of the Pediatric Emergency Department (PED) visits for young allergic patients with respiratory or cutaneous symptoms during the first wave of the coronavirus disease 19 (COVID-19) pandemic in 2020 with the same period in 2019, evaluating the percentage of positive cases to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). We carried out a retrospective analysis using data from young patients who visited the PED with cutaneous or respiratory symptoms in the period from 20th February to 12th May of the years 2020 and 2019. Data on allergy and COVID-19 nasal swab were also collected. We observed eleven (28.2%) PED visits for allergic patients with respiratory or cutaneous symptoms for the period from 20th February to 12th May of the year 2020 and ninety-three (31.8%) PED visits for the same time frame of the year 2019 (p=0.645). Only a two-month-old child out of 39 patients with non-allergic respiratory or cutaneous symptoms resulted positive for SARS-CoV-2. Specifically, we found for all the PED visits: 21 (7.2%) in 2019 vs 2 (5.1%) in 2020 for patients with urticaria/angioedema or atopic dermatitis (p=0.634); 3 (1.0%) in 2019 vs 3 (7.7%) in 2020 for patients with anaphylaxis (p=0.003); 19 (6.5%) in 2019 vs 2 (5.1%) in 2020 for those with asthma (p=0.740); 11(3.8%) in 2019 vs 1(2.6%) in 2020 for those with lower respiratory diseases, excluding asthma (p=0.706); 39(13.4%) in 2019 vs 3 (7.7%) in 2020 for those with upper respiratory diseases (URDs) (p=0.318). We also showed a substantial decrease (~80%) in all PED visits compared with the same time frame in 2019 (absolute number 263 vs 1211, respectively). Among all the PED visits a significant reduction was mostly found for URDs [155 (12.8%) in 2019 vs 17 (6.5%) in 2020; p=0.045)]. The total number of PED visits for allergic patients with respiratory or cutaneous symptoms dropped precipitously in 2020. It is very tricky to estimate whether it was a protective action of allergy or the fear of contagion or the lockdown or a reduction in air pollution that kept children with allergy from visiting the PED. Further studies are needed to better understand the impact of underlying allergies on COVID-19 susceptibility and disease severity.