The 10 million-plus Americans who have allergic asthma — where allergy symptoms that result in asthma are triggered not only by seasonal plants but also environmental threats, such as cat dander, dust mites and mold — need to be especially careful over the next few months. New research has revealed some additional flu-related health risks for this population that warrant taking extra protective measures to stay healthy when colds and flu are going around.
Researchers at The University of Texas Southwestern Medical Center at Dallas learned that certain flu-fighting immune cells are disabled in people with allergic asthma and that exposure to allergens may depress their anti-flu immune response even further, says the study author, Michelle Gill, MD, PhD, assistant professor of pediatrics. This means that people with allergic asthma may experience more intense flu symptoms… take longer to recover… and are at higher risk for serious complications such as pneumonia.
Dr. Gill’s study included 56 people, ages three to 35. Twenty-six had allergic asthma while the others had no known allergies. Researchers took blood samples and then isolated immune cells that direct the body’s response to viral infections. When the blood of those with allergic asthma was exposed to the flu virus and the relevant allergen, the cells’ ability to fight the flu virus was impaired about half the time. The same thing happened when the cells were exposed to rhinovirus, which causes the common cold. A future study will examine whether the opposite response also occurs — that is, whether exposure to flu viruses blocks the allergic response, which could, ironically, make patients lessallergic while they are sick with a cold or flu.
In the meantime, what we now know is that a person with allergic asthma (triggered by dust mites, for instance) is likely to have more trouble fighting off a flu or cold virus when the allergic trigger is also in play (the house isn’t clean). So, said Dr. Gill, the important take-home finding here is that controlling the allergen triggers is especially important during flu season.