Changes in Prevalence of IgE Sensitization and Allergenic Exposition over a 10-Year Period in a Tropical Region

Introduction: Multiple antigen environmental sources have been identified as possible causes of allergies, but few studies have evaluated changes in the sensitization profiles over time. The aim of this study was to evaluate the changes in IgE sensitization and exposure to dust mites, cats, dogs, and cockroaches over a 10-year period. Methods: During a period of 10 years among patients with asthma, rhinitis and/or atopic dermatitis, we evaluated the annual frequency of atopy to Dermatophagoides farinae, Dermatophagoides pteronyssinus, Blomia tropicalis, Canis familiaris, Felis domesticus and cockroaches (Periplaneta americana and Blatella germanica). Exposure to sources was also assessed using questionnaires (Pets) or direct counts (House dust mites and cockroaches). The association between some risk factors and the prevalence of atopy was explored. Results: A total of 6,000 records were included. Among the patients, 82% had IgE sensitization to at least one of the six allergenic sources. Sensitization to Dermatophagoides spp. was the most frequent (>78%). Exposure and sensitization in the first decade of life to Dermatophagoides spp. seem to determine the molecular spreading to other allergenic sources. Exposure to Blomia tropical increases significantly over time (year 2015; 38% vs. year 2022; 51%, p 0.03). Exposure to dogs was higher than with cats but association between atopy and exposure was stronger with cats (OR 27.4, 95% CI: 22.3–33.6, p < 0.01). Conclusion: Exposure and sensitization in the first decade of life to Dermatophagoides spp. determine the molecular spreading of IgE antibodies to other allergenic sources. Household exposure to dogs and cats seems to be important for the subsequent development of atopy. Sensitization to B. tropicalis and cockroach appears to be mostly from cross-reactivity rather than direct exposure.