EXPOSURE TO DOMESTIC-ANIMALS AND RISK OF IMMUNOLOGICAL SENSITIZATION IN SUBJECTS WITH ASTHMA

Background: The objective of the study was to determine whether exposu re to domestic animals plays a significant role, beyond atopy, in the development of immediate sensitization to animal-derived antigens. . M ethods: To test this hypothesis, 200 subjects with asthma (85 male sub jects and 115 female subjects; mean age, 37 +/- 16 years) seen consecu tively in an asthma clinic were enrolled in a cross-sectional survey. Each subject answered a questionnaire about allergy symptoms and past and current exposure to domestic animals. Skin prick testing with extr acts of common inhalant allergens including antigens from eight specie s of animal (cat, dog, horse, rabbit, rat, mouse, guinea pig, and hams ter) were also carried out. Results: Seventy-nine percent of subjects were atopic, and 91% had kept animals at home at some point (figures w ere 80% for dogs, 68% for cats, 23% for rabbits, and 20% for rodents). Using two-by-two tables, we showed that skin reactivity to at least o ne animal antigen was strongly linked to atopy (86% of atopic subjects had skin reactions as compared with 34% of nonatopic subjects; p < 0. 001) but not to previous and current exposure to domestic animals (78% of both exposed and never exposed subjects). However, with the use of logistic regression, the determinants of skin reactivity to animals w ere atopy (p < 0.001), followed by cumulative duration of exposure to domestic animals (p < 0.01). The number of animals times the number of species times the duration of exposure was also a significant determi nant of skin reactivity (p = 0.05). Conclusions: We conclude that beyo nd the predominant role of atopy, cumulative duration of exposure to d omestic animals is a significant determinant for immediate sensitizati on to animal-derived antigens in subjects with asthma.