Prevalence of basidiomycete allergy in the USA and Europe and its relationship to allergic respiratory symptoms.

A total of 701 adults living in the USA or Western Europe who had symptoms of allergic respiratory disease were skin prick tested with extracts prepared from eight basidiomycetes species and four Fungi Imperfecti species. In these subjects, the presence of asthma, rhinitis, or both was determined by questionnaire. Overall, 178/701 (25.4%) of the participants reacted to at least one basidiomycete extract. There was no difference in the prevalence of reactivity detected in the USA and Europe (P < 0.005); however, the prevalence of reactors in individual centers from both areas varied significantly. Psilocybe cubensis was the most potent allergen source in both the USA (12.3% reacted) and Europe (16.0%). Pleurotus ostreatus was second overall (10.6%) and in the USA (10.7%), and third in Europe (10.3%). Pisolithus tinctorius and Coprinus quadrifidus produced the least potent allergens, with only 5.4% of the population reacting. There was a significant relationship (P < 0.005) between basidiospore reactivity and the presence of atopy, asthma, and asthma and rhinitis. Basidiospore reactivity was not associated with the presence of rhinitis alone (P = 0.312). These results suggest that basidiomycetes are important sources of aeroallergens in geographically disparate regions and may be particularly important in patients with asthma.