Atopy linked to asthma relapse in children
In paediatric patients with asthma, viral infection has minimal effect on measures of acute severity and clinical recovery, a study has found. Meanwhile, the risk of asthma relapse is elevated in the presence of atopy.
“This information is potentially important in identifying the children who are more likely to have an asthma relapse, with substantial burden placed on their parents/carers and families,” said a team of Australia-based investigators. “Data could also aid in counselling parents of children with acute asthma regarding the potential length of symptoms and consequences.”
In the study, a total of 244 children (median age 4.5 years; 65.2 percent boys) who presented with acute asthma to the emergency departments underwent a nasopharyngeal aspirate examination and an allergen skin prick test.
Polymerase chain reaction (PCR) results for viruses/atypical bacteria were positive in 184 (81.7 percent) children, with PCR-positive patients more likely to be younger. Majority (75.1 percent) had human rhinovirus, while 14.2 percent had codetection of up to three micro-organisms. Mycoplasma pneumoniae and Chlamydophila pneumoniae were rarely detected. There were 160 children who had atopy. [Arch Dis Child 2017;doi:10.1136/archdischild-2017-312982]
On multivariate regression analysis, PCR positivity had little impact on asthma outcomes, namely acute severity and recovery. PACQLQ (asthma quality of life questionnaires for parents) score was the only parameter that differed significantly between the PCR-positive and -negative groups, with PCR positivity associated with better PACQLQ scores at presentation (p=0.028) and during recovery (day 14, p=0.043; day 21, p=0.022).
On the other hand, atopy was significantly associated with representation for asthma. Compared with those without the syndrome, children with atopy were highly likely to relapse and represent for asthma deterioration by day 14 (odds ratio, 1.11; 95 percent CI, 1.00 to 1.23; p=0.042).
The investigators pointed out that the observed difference in PACQLQ scores between PCR-positive and -negative patients “suggests that other extrinsic factors (eg, traffic-related air pollution) may have triggered the asthma exacerbations of children with PCR-negative state, [thereby] resulting in a longer duration of symptoms.”
“We conclude that although asthma exacerbations are commonly associated with viruses, their presence does not impact on recovery… Also, M. pneumoniae and C. pneumoniae are rare triggers of acute asthma in young children,” they added.
While speculating that atopy might be associated with delayed resolution in light of the syndrome’s association with an unscheduled doctor visit within 14 days, the investigators acknowledged that addressing such possibility would require further prospective studies.