Allergens, viruses and asthma

Asthma attacks severe enough to send patients to hospital could be triggered off by a combination of viruses and allergens. Researchers found that the risk of hospitalisation for an asthma attack was highest when patients had viral infections and were exposed to allergens like dust mites and pets. Although shielding oneself from viruses may be difficult asthmatics who are susceptible to allergic reactions can take care to avoid allergy triggers. Both environmental irritants and viral respiratory infections are known to exacerbate asthma which is a chronic lung disease marked by attacks of wheezing, breathlessness and coughing. Researchers in Manchester, UK have recently considered whether allergens and viruses conspire to set off these attacks. They compared 60 adults hospitalised for asthmatic attacks (status asthmaticus) with others who either had stable asthma or did not have it at all. They found that 66% of the patients admitted to hospital for asthma were sensitised and exposed to either house dust mite, cat or dog allergens as compared with patients of stable asthma (37%) and inpatient controls (15%). Their findings suggest that domestic exposure to allergens combines with viruses in sensitised patients and increases the risk of hospitalisation by threefolds. Moreover such exposure coupled with evidence of a viral infection increases that risk by more than eightfold. A viral infection by itself was not linked to a higher hospitalisation risk. The conclusion of this study was that the interaction of common allergens and viruses possibly increases the risk of asthma. Therefore in the absence of effective strategies to control viruses attention should be paid to reducing exposure to allergens.

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