VERONA – Childhood wheezing may be triggered by viral respiratory tract infections in otherwise healthy children or may be a sign of childhood asthma. While children who suffer from childhood asthma also wheeze when exposed to a variety of other triggers, such as exercise or allergens, in clinical practice the distinction may not be as straightforward.
The practical difficulty in differentiating between these different conditions that may underlie a similar clinical presentation makes it difficult to decide on diagnostic procedures, and more importantly, treatment strategies.
Among preschool children who wheeze, two different groups can be identified according to Dr Laura Tenero and colleagues from the Clinica Pediatrica, Università di Verona, Italy: children who have a viral infection and those who respond to multiple triggers. While both groups suffer from a respiratory tract infection, the child with “viral wheezing” has symptom-free periods between episodes and his wheeze is triggered only by viruses.
In contrast, children with multiple trigger wheezing, although being highly susceptible to viral infections which also represent the most common trigger for their symptoms, also wheeze when exposed to a variety of other triggers, such as exercise or allergens.
To distinguish between these different phenotypes of wheezing, and consequently choose appropriate therapy, represents a major challenge.
In particular, transient wheezers do not improve with maintenance treatment with inhaled corticosteroids. On the other hand these are definitely useful in children with wheeze due to asthma. Increasing evidence favours the potential role of leukotriene receptor antagonists in treatment of preschool children with recurrent wheezing. Oral steroids are not indicated to control acute wheezing, unless severe disease is expected in non-atopic children.
The use of inhaled or oral corticosteroids in preschool wheezers is common in clinical paediatric practice. In a study of 700 children between the ages of 10 months and 60 months presenting to a hospital with mild-to-moderate wheezing associated with a viral infection, oral prednisolone was not shown to be superior to a placebo.
“Therefore, the indiscriminate use of oral corticosteroids cannot be recommended in children without the classic atopic asthma phenotype”, writes Dr Tenero in the Italian Journal of Pediatrics. Inhaled corticosteroid (ICS) courses are proposed even more frequently than oral ones for children presenting with wheeze.
In a recent meta-analysis of 29 randomized trials, which included 3.592 children who were receiving inhaled corticosteroids for at least four weeks in the clinical setting of frequent wheezing episodes, it was concluded that inhaled corticosteroids were useful in such a paediatric population in reducing frequency of exacerbations and symptoms and improving lung function.
However, a significant response to ICS treatment was observed in the children with frequent symptoms, a family history of asthma, or both, but not in those without a family history.
Therefore, according to Dr Tenero, the conclusion that ICSs are useful in infants and preschool children with wheeze/asthma can represent a misleading message to the reader regarding the potential usefulness of a maintenance treatment with ICSs in the group of transient wheezers.
“To the best of our knowledge, for this group, at present, there is no indication that a maintenance treatment with ICCs can be effective in reducing the frequency or the severity of wheezing".
“The main clinical dilemma in dealing with preschool children with wheezing is represented by the difficulty to predict the future development of the disease in the
individual patient. At present, we know that the response to systemic and inhaled steroids in this age group is poor, due to the prevalence of viral wheeze in these
children. Therefore, the therapeutic options potentially available for preschool children with episodic non-atopic wheeze are ß2-agonists to control exacerbations, along
with intermittent or prophylactic leukotriene receptor antagonists, whereas high dose nhaled corticosteroids are not recommended and oral corticosteroids should be
considered only in severely ill children in the hospital setting”.
Tenero L. Ital J Pediatr. 2009 Dec 24;35(1):43
Panickar J. N Engl J Med. 2009 Jan 22;360(4):329-38.
Castro-Rodriguez et al. Arch Dis Child. 2009 Nov 27
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