The possible influence of the environment on respiratory allergy: a survey on immigrants to Italy

Background Respiratory allergy is influenced and determined by genetic and environmental factors. Migration is a good model to indirectly evaluate the possible influence of environment. Objective To assess the clinical characteristics of respiratory allergy in immigrants to Italy, in comparison with the Italian population. Methods The clinical/demographic data of those immigrants stably living in Italy and referred for the first time to allergy services for respiratory allergy were collected in a multicenter survey. All the patients underwent a standard diagnostic workup. A matched Italian population was also examined. Results Six hundred ninety-eight immigrants and 859 Italians had at least one positive skin test and were analyzed. Most of the patients were referred to the allergy units by their general practitioners. In those patients, the demographic characteristics were not different, except for family size. Immigrants had less family history of atopy. Only 16% had a clinical history of allergy before migration. The time elapsed between migration and onset of symptoms was 5.3 ± 3.1 years, with a minimum of 0.5 and a maximum of 7 years. A higher rate of monosensitization was seen among immigrants, and the severity of their asthma/rhinitis was greater than in Italians. No difference was seen in the pattern of sensitizations. Conclusion In this population of immigrants, environmental factors play a relevant role in the onset of respiratory allergies.