The diagnosis of asthma in younger children is difficult and based on clinical assessment of symptoms and results of physical examination. Respiratory wheeze has traditionally been used to define asthma in young children but there have been concerns that this definition is too narrow and may miss children with milder asthma who do not wheeze but have other symptoms such as cough or shortness of breath.
Here is what wheezing sounds like (click to play the embedded video):
This study from Denmark included 411 children born to asthmatic mothers that were followed prospectively to age 7 years (313 had the full follow-up).
The total number of acute clinic visits for asthma symptom was associated with later asthma (P < .0001), whereas the presence of wheeze at these visits was not (P = .5). The number of clinic visits for troublesome lung symptoms was also associated with later asthma in children who had never presented with any wheeze.
A quantitative global assessment of significant troublesome lung symptoms in the first 3 years of life is a better predictor of asthma than assessment of wheeze. Doctor-diagnosed wheeze is not a prerequisite for the diagnosis of asthma, and relying on the symptom of wheeze will likely be an important cause of undertreatment.
Editor’s note: The findings of this study are significant considering the widely used modified Asthma Predictive Index relies on 4 wheezing episodes during the past year (http://www.jacionline.org/article/S0091-6749(10)01034-1/abstract). Future predictive tools may need to incorporate symptoms other than wheezing to achieve better accuracy and clinical applicability.
Modified Asthma Predictive Index (API) (click to enlarge the image).
"To wheeze or not to wheeze": That is not the question. Skytt N, Bønnelykke K, Bisgaard H. J Allergy Clin Immunol. 2012 Aug;130(2):403-407.e5. Epub 2012 Jul 4.