Prevalence of sensitization to Alternaria in allergic patients in Italy

Background: The actual prevalence of sensitization to Alternaria is not known, partly due to the unreliability of diagnostic extracts. Objective: To assess skin positivity to extracts of Alternaria in a wide population of Italian patients suffering from respiratory symptoms using a biologically standardized extract. Methods: A total of 2942 patients were skin prick tested with Alternaria, and a panel of common inhalant allergens. Blood samples for specific IgE quantitation were taken both from patients positive and from patients negative (control group) to Alternaria extract. Results: Three hundred six patients (10.4%, ranging from 1.8% in Turin to 29.3% in Cagliari) were positive to Alternaria; 37 were sensitized to only this mold, while the remaining 269 were sensitized to at least one other allergen. Of the Alternaria-positive patients, 79.7% suffered from rhinitis and 53.3% from asthma, either alone or associated with other symptoms. Conclusions: We suggest that, at least in Italy and in countries with similar climatic and environmental situations, standardized Alternaria extract should be included in the panel commonly used in investigating the allergen responsible in patients suffering from respiratory allergy.