Synergism between allergens and viruses and risk of hospital admission with asthma: case-control study

Top Cited Papers
Publisher Website
Google Scholar
Abstract
Objective: To investigate the importance of sensitisation and exposure to allergens and viral infection in precipitating acute asthma in adults resulting in admission to hospital. Design: Case-control study. Setting: Large district general hospital. Participants: 60 patients aged 17-50 admitted to hospital over a year with acute asthma, matched with two controls: patients with stable asthma recruited from the outpatient department and patients admitted to hospital with non-respiratory conditions (inpatient controls). Main outcome measures: Atopic status (skin testing and total and specific IgE), presence of common respiratory viruses and atypical bacteria (polymerase chain reaction), dust samples from homes, and exposure to allergens (enzyme linked immunosorbent assay (ELISA): Der p 1, Fel d 1, Can f 1, and Bla g 2). Results: Viruses were detected in 31 of 177 patients. The difference in the frequency of viruses detected between the groups was significant (admitted with asthma 26%, stable asthma 18%, inpatient controls 9%; P=0.04). A significantly higher proportion of patients admitted with asthma (66%) were sensitised and exposed to either mite, cat, or dog allergen than patients with stable asthma (37%) and inpatient controls (15%; PConclusions: Allergens and viruses may act together to exacerbate asthma. What is already known on this topic Studies on segmental allergen challenge of the lung and experimental rhinovirus infection show synergistic effects between allergens and respiratory virus infection No studies have investigated an interaction between sensitisation, exposure to allergens, and virus infections in real life exacerbations of asthma What this study adds Allergens and viruses may act together to exacerbate asthma, indicating that domestic exposure to allergens acts synergistically with viruses in sensitised patients, increasing the risk of hospital admission Strategies to reduce the impact of asthma exacerbations in adults should include interventions directed at both viruses and reducing exposure to allergens