Clinical Importance of Alternaria Exposure in Children

Abstract

The fungus Alternaria is known to be allergenic and is one of the most common fungi worldwide. We investigated the extent to which exposure to Alternaria increases the severity of asthma. We undertook a prospective cohort study in Australia of 399 school children who had positive skin tests to one or more aeroallergens. Airway responsiveness to histamine, wheeze, and bronchodilator use in 1 mo was measured five times between 1997 and 1999. Airway hyperresponsiveness was defined as PD(20)FEV(1) = 3.9 micromol histamine. Airborne concentrations of Alternaria spores were measured throughout the study, and mean daily concentrations over 1 mo ranged from 2.2 to 307.7 spores/m(3) of ambient air. Using generalized estimating equations, we found that airway responsiveness, wheeze, and bronchodilator use increased significantly in association with increased spore concentrations and that the increase in airway responsiveness was greater in children sensitized to Alternaria than in other children (p = 0.01). The odds ratio for airway hyperresponsiveness in children sensitized to Alternaria was 1.26 (95% CI, 1.14 to 1.39) after an increase in mean exposure of 100 spore/m(3)/d over 1 mo. These results suggest that Alternaria allergens contribute to severe asthma in regions where exposure to the fungus is high.

Exposure to Alternaria alternata in US homes is associated with asthma symptoms

“…5,6,8,12 In our population, active asthma symptoms were slightly more prevalent among children than among adults (8.4% vs 6.5%; P = .12 for difference), but the observed effect was not modified by age. Although the point estimate for the association was higher among children than among adults, there was no evidence of significant interaction.…”

“…[3][4][5]8,15 Sensitization to Alternaria has been found to be significantly higher among subjects with asthma than among subjects without asthma. 35 We were unable to ascertain Alternaria sensitivity among the study participants because we lacked detailed information on their sensitization status.…”

Indoor airborne fungi and wheeze in the first year of life among a cohort of infants at risk for asthma

“…Numerous studies (primarily cross-sectional in design) involving older children and adults have reported at least one positive association between total airborne fungal or bacterial counts, or specific fungal taxa including Penicillium, Cladosporium, Aspergillus or Alternaria species, and respiratory symptoms including cough, wheeze and asthma (Platt et al, 1989;Strachan et al, 1990;Bjornsson et al, 1995;Li and Hsu, 1997;Garrett et al, 1998;Dharmage et al, 2001;Downs et al, 2001). Null findings in all age groups also have been reported for both airborne (Su et al, 2001) and dustborne fungi (Wickman et al, 1992;Verhoeff et al, 1994).…”

A Large Subgroup of Mild-to-Moderate Asthma Is Persistently Noneosinophilic

“…Notably, however, our analysis identified a novel cluster characterized by asthma occurring in nonobese males who develop asthma in childhood and who have sensitivity to Alternaria. Male children frequently have sensitization to Alternaria, and epidemiologic studies suggest that, unlike other forms of male childhood asthma, it does not remit (42)(43)(44). Thus, adult males with asthma and Alternaria sensitivity may represent a cohort of males whose asthma persists from childhood.…”