Differential effects of outdoor versus indoor fungal spores on asthma morbidity in inner-city children

Abstract

Background While sensitization to fungal allergens is prevalent in inner-city children with asthma, the relationship between fungal exposure and morbidity is poorly understood. Objective We examined relationships between fungal sensitization, exposure and asthma morbidity in inner-city children. Methods Participants were 5–11 years old and enrolled in the Inner-City Asthma Study. This report includes the subset of children with at least 1 positive skin test to a fungal allergen extract; for these children, indoor and outdoor airborne culturable fungi were measured at baseline and throughout the 2 year study. Asthma morbidity measures were collected prospectively. The primary outcome was symptom days per 2 weeks. Results At baseline, children with a positive skin test to a fungal allergen extract had significantly more symptom days compared to those without positive skin test to any fungal allergen extract (6.3 vs 5.7 days per 2 weeks, p=0.04). During the study, elevations in total fungal exposure and indoor Penicillium exposure were associated with increases in symptom days and asthma unscheduled visits. Indoor exposures to total fungi and to Penicillium were associated with significant increases in unscheduled visits, even after controlling for outdoor fungal levels. Adverse effects associated with exposure to a specific fungus were stronger among children with positive skin test to that fungal allergen extract compared to skin test negative children. Conclusion Outdoor fungal exposure is primarily associated with increased asthma symptoms and increased risk of exacerbations in this population.

Diversity and dynamics of airborne fungi in São Luis, State of Maranhão, Brazil

“…The relationships among allergic exposure, the fungal presence in indoor and outdoor environments and consequent allergic diseases are not fully understood 5,6 . Therefore, it is important to know both the frequency of certain airborne fungi and their distributions according to the season and the main environment (i.e., indoor or outdoor) in order to evaluate their correlations with respiratory symptoms related to allergic processes [7][8][9] .…”

Indoor Environmental Control Practices and Asthma Management

“…51 The prevalence of mold sensitization in children with persistent asthma is approximately 50%, and the most common species to which children are sensitized and exposed are Alternaria, Aspergillus, Cladosporium, and Penicillium. 52 Although Alternaria and Aspergillus are derived from outdoor sources, they are present indoors and may be clinically relevant. 53 The National Survey of Lead and Allergens in Housing found that 56% of homes had levels of some molds above thresholds observed to be associated with asthma symptoms.…”

“…54 Children sensitized and exposed to the major indoor molds appear to be at greater risk of asthma exacerbations. 52 Remediation of mold has been shown to reduce symptoms and medication use in several populations, and its effects may not depend on whether the population is sensitized to mold. 55,56 The evaluation of a patient with persistent asthma includes an assessment of sensitization to the major indoor molds, which can be accomplished with specific IgE testing performed on a blood sample or through referral to a board-certified allergist for skin testing.…”

A Research Agenda on Assessing and Remediating Home Dampness and Mold to Reduce Dampness-Related Health Effects

“…al. 2010), with the latter outcome also having dose-response associations with total indoor fungi (Pongracic et. al.…”