The role of fungal spores in thunderstorm asthma.

STUDY OBJECTIVES To document the existence and investigate the etiology of "thunderstorm asthma," which has been reported sporadically over the past 20 years. DESIGN We assessed the relationship between thunderstorms, air pollutants, aeroallergens, and asthma admissions to a children's hospital emergency department over a 6-year period. RESULTS During thunderstorm days (n = 151 days) compared to days without thunderstorms (n = 919 days), daily asthma visits increased from 8.6 to 10 (p < 0.05), and air concentrations of fungal spores doubled (from 1,512 to 2,749/m(3)), with relatively smaller changes in pollens and air pollutants. Daily time-series analyses across the 6 years of observation, irrespective of the presence or absence of thunderstorms, demonstrated that an increase in total spores, equivalent to its seasonal mean, was associated with a 2.2% (0.9% SE) increase in asthma visits. CONCLUSIONS Our results support a relationship between thunderstorms and asthma, and suggest that the mechanism may be through increases in spores that exacerbate asthma. Replication in other climates is suggested to determine whether these findings can be generalized to other aeroallergen mixes.