Outdoor fungi and child asthma health service attendances

Abstract

Asthma is a significant global public health issue. Severe asthma exacerbations can be triggered by environmental factors and require medical care from health services. Although it is known that fungal exposure may lead to allergic sensitization, little is understood about its impact on asthma exacerbations. This review aims to examine whether outdoor fungi play a significant role in child asthma exacerbations. Systematic search of seven electronic databases and hand searching for peer-reviewed studies published in English, up to 31 August 2013. Inclusion criteria were study population aged <18 yr, diagnosis of asthma, attended a health service; outdoor fungi exposure was reported. Quality and risk of bias assessments were conducted. Due to significant heterogeneity, meta-analysis was not conducted. Of the 1896 articles found, 15 were eligible. Findings were not consistent, possibly due to methodological variations in exposure classifications, statistical methods and inclusion of confounders. Cross-sectional studies found no or weak associations. All but one time series studies indicated an association that varied between fungal species. Increasing evidence indicates that asthmatic children are susceptible to asthma exacerbations when exposed to outdoor fungal spores. There is limited understanding of the contributions of different fungal species. Research is needed to investigate interactions of outdoor fungi with pollen, air pollutants and respiratory viruses.

Association between transported Asian dust and outdoor fungal concentration during winter in a rural area of western Japan

“…However, the mechanism underlying the AD-induced exacerbation of asthma remains unclear. Several studies have shown that outdoor fungi were associated with an increase of emergency department visits, hospitalizations, and aggravation of asthma symptoms in patients with asthma [16–18]. However, according to the results of the present study, heavy exposure to outdoor fungi does not represent a likely cause for the exacerbation of asthma caused by exposure to AD.…”

“…Although AD has been suggested to exert allergic and toxic effects, it remains uncertain as to which components of AD are associated with the exacerbation of asthma. Several studies have reported that outdoor fungi can increase emergency department visits and hospitalization for asthma exacerbation and can aggravate asthma symptoms [16–18]. AD has also been shown to carry microbial agents [19] and a few studies have reported increases in the abundance of several fungal taxa during heavy AD days [20–22].…”

Pulmonary ORMDL3 is critical for induction of Alternaria-induced allergic airways disease

“…Stratifying patients with severe asthma into 2 groups on the basis of their response to fungal exposure reveals that the patients who respond to fungal allergens have earlier onset symptoms and require more oral steroid therapy than do those who do not and experience a greater number of asthma exacerbations 41, 42, 43. GWAS data predict that elevated ORMDL3 expression increases the risk of severe asthma and asthma exacerbations; thus, given the association between ORMDL3 and Alternaria -induced AHR revealed in the present study, it would be pertinent to determine whether SNPs in the 17q21 locus are associated with severe fungal-associated asthma phenotypes.…”

Allergy in severe asthma

“…Alternaria or Cladosporium spp sensitization was associated with asthma severity in the European Community Respiratory Health Survey. Furthermore, a recent paper has shown that fungal sensitization in children with persistent asthma is associated with disease severity (113) and a 2014 review has shown increasing evidence that sensitized asthmatic children may be susceptible to asthma exacerbations when exposed to outdoor fungal spores and that the severity of exacerbation may vary with different fungi species (114).…”