Onset of allergy and asthma symptoms in extra‐European immigrants to Milan, Italy: possible role of environmental factors

BACKGROUND: Allergy and asthma are typical disorders of the affluent societies. Migrants from developing to industrialized countries seem to be at increased risk of allergy and asthma development. OBJECTIVE: To evaluate time of onset, spectrum of sensitization and clinical features in a population of extra-European immigrants to Milan, Italy, complaining of allergy and asthma symptoms. METHODS: Data regarding 243 extra-European immigrants checked at an allergy clinic from 1994 to 2000 were collected retrospectively. The demographic data were compared with those of the extra-European immigrants living in Milan at the end of 1999. RESULTS: The patients were complaining of asthma (63.7%), rhinoconjunctivitis (56.7%), rhinitis alone (21%) or urticaria (3%). One hundred and eighty-seven out of 222 patients (84.3%) declared they were healthy before migrating and allergy/asthma symptoms started to appear after their arrival in Italy, namely after an average period of 4 years and 7 months. The proportion of male patients was lower than the proportion of men in the extra-European immigrant population (48% vs. 55%), suggesting that in adult immigrants allergy and asthma are more common in women than in men. Furthermore, there was an over-representation of Central-South Americans attending the clinic, which seemed to be due to a genetic predisposition to allergy/asthma development. When data were analysed for single countries, a trend towards an increased risk of allergy and asthma was found in immigrants from all Central-South American countries. A skin test positivity for at least one inhalant allergen was found in 196 out of 232 patients (81%), and the spectrum of allergic sensitization was similar to that of the Italian population living in the North of Italy. CONCLUSION: Most extra-European immigrants declared that they were healthy at home and that allergy and asthma symptoms had appeared after immigration to Milan; lifestyle and environmental factors in a western industrialized city seem indeed to facilitate allergy/asthma onset in immigrants from developing countries. Allergy/asthma risk seems to be different in different ethnic groups.