Investigating the association between allergic diseases and COVID-19 in 400 Iranian patients.

Introduction: Allergic diseases could play a role of a predisposing factor for coronavirus disease 2019 (COVID-19). The aim of this study was to investigate allergic comorbidity and its association in COVID-19 patients.

Methods: Demographic data, clinical manifestations, laboratory reports, and radiologic findings, together with underlying comorbidity of patients, were studies. Allergic diseases were identified by using the standard GALEN questionnaire. The severity of COVID-19 was assessed by a visual analog scale (VAS) and an intensive care unit (ICU) report.

Results: Out of 400 COVID-19 patients admitted in the hospital, 158 (39.5%) presented with different allergic diseases, and a reverse association was observed between having allergic comorbidity and severity of COVID-19 infection (P = 0.005, relative risk = 0.96; 95% Confidence Interval (95% CI): 0.77-1.19). The respective frequency of asthma, allergic rhinitis (AR), chronic rhinosinusitis (CRS), atopic dermatitis, chronic urticaria, and food or drug allergy was 7.3%, 16%, 1.8%, 5%, 10% and 13.3%. Significantly, only AR was reversely associated with the severity of COVID-19 (P = 0.02, relative risk = 0.45; 95% CI: 0.77-1.19). Additionally, 43% of the patients presented hypoxemia, and 93.5% had chest CT scan involvement. Interestingly, patients with allergic diseases had significantly lower hypoxemia and chest CT involvement as compared with non-allergic patients (P = 0.002 and 0.003, respectively).

Conclusion: The results of this study established that allergic diseases were not determined to be a predisposing factor for the severe acute respiratory syndrome (SARS) due to coronavirus 2 (SARS-CoV-2) infection. Significantly, AR patients developed mild clinical manifestations of COVID-19 and admitted to ICU as compared to non-AR patients.