Viral infection common, leads to more acute symptoms in children with uncontrolled asthma

Angela Duff Hogan, MD, FAAAAI, FACAAI, FAAP

Viral infections are the most common cause of children’s acute wheezing/asthma exacerbations. It would be helpful to be able to predict which child will have the most difficulty handling the viral infection at the time of an acute exacerbation. This study evaluated multiple risk factors associated with increased respiratory symptoms during an acute viral infection.

The authors sought to answer if the viral-induced asthma attack was more severe if the patient presented with uncontrolled vs. controlled asthma in the preceding month by measuring ACT score in the ED. They found that those children with poorly controlled asthma at the time of their viral infection/exacerbation had more acute symptoms.

This study demonstrated that this difference in the severity of symptoms was not correlated with viral load. Even though viruses increase allergic airway inflammation, those children with uncontrolled asthma and viral infections had more significant enhancement of inflammation as evidenced by periostin levels obtained by nasal filter paper absorption. The authors stated that nasal periostin levels could be a marker for poor asthma control during the viral exacerbation and suggest who could be at risk for a more severe exacerbation.

Also, this study reaffirms that there is a synergistic additive effect on inflammation induced by the presence of atopy and respiratory viral infections, especially rhinovirus.

In an ideal setting, knowing which child presenting with an acute asthma exacerbation needs to be observed longer, admitted and followed up tomorrow, as well as which child needs more medications, steroids or long-term follow-up would be helpful. This study reaffirms that those children with rhinovirus infections, poorly controlled asthma prior to their attack and a history of atopy are at greater risk for more severe exacerbations as measured by acute symptoms.

One should consider a device that measures nasal periostin like FENO instruments to help determine asthma exacerbation severity from a proinflammatory perspective.

Giorgio Ciprandi, MD

The link among allergy, infections and asthma exacerbations is well known and still deserves adequate attention in clinical practice. This study confirms previous research in this topic. The outcomes are not striking but are relevant as they confirm the important link among allergy, infections and asthma exacerbations.

In particular, the novelty of this study is its underlining of the importance of uncontrolled asthma. Unfortunately, the authors used ACT scores to measure asthma control. This questionnaire evaluates the perception of asthma control, without considering objective variables.

Still, it is important to stress the concept that asthma should be controlled. Many asthmatics are still not well controlled. This finding should give pause to the fact that much effort is still needed to achieve the goal of asthma treatment — that is, control — because uncontrolled asthma is a cat biting its tail. The results of this study underline this goal.

While this study measured some biomarkers and virus infection details that are not suitable in clinical practice, blood eosinophil count is a reliable marker of allergic inflammation. Thus, it can be routinely assessed in clinical practice. Also, functional data should be considered.

Viral infections cause a cascade of inflammatory events, including cytokine release. It is well known that RV increases IL-8 at nasal level. IL-8 accounts for mucopurulent rhinorrhea.

Interestingly, it has been very recently demonstrated that in children with asthma exacerbations (AE), the number of previous AE is the most important risk factor for new AE. Thus, preventing AE is mandatory. Different ways may exist to prevent AE, including allergen immunotherapy and immune response manipulation using natural substances such as probiotics, vitamin D and herbal medicines.