Wheezing is a heterogeneous symptom in preschool children. “Not all that wheezes is asthma” is a common expression and it reflects the difficulty of predicting whether symptoms will pass, or persist and develop into asthma.
30% of children have wheezing during respiratory infections before their third birthday. Why?
Infants are prone to wheeze because of:
- anatomic factors related to the lung and chest wall
- viral infections that lead to wheezing
Wheezing in Children - Phenotypes (click to enlarge the image).
Not every wheeze is indicative of asthma but prediction of asthma in persistent wheezers is possible. Testing for allergy in these infants is worthwhile and can be of significant value in avoidable allergens.
Childhood asthma phenotypes (click to enlarge the image).
This prospective study evaluated if inflammatory markers in exhaled breath condensate (EBC) at preschool age are associated with wheezing later in life, at school age. Inflammatory markers IL-2, IL-4, IL-8, IL-10, sICAM were measured in 200 children.
Persistent wheezers had elevated levels of all interleukins at preschool age compared to children who never wheezed. However, the markers did not differ between the persistent and transient wheezers.
The study demonstrated that 5-year-old children with persistent wheezing already had elevated exhaled inflammatory markers at preschool age compared to never wheezers. However, the fact that there was no statistical difference between persistent and intermittent users limits the practical implications of this study.
The Modified Asthma Predictive Index (mAPI) is probably the best predictive tool in children who are not yet able to do perform a spirometry (younger than age 5). Here is how the index works:
Modified Asthma Predictive Index (mAPI) (click to enlarge the image).
van de Kant KDG, Jansen MA, Klaassen EMM, van der Grinten CP, Rijkers GT, Muris JWM, van Schayck OCP, Jöbsis Q, Dompeling E. Elevated inflammatory markers at preschool age precede persistent wheezing at school age. Pediatr Allergy Immunol 2012: 23: 259–264.
Image source: OpenClipArt, public domain.