RESUMO
BACKGROUND: Allergen exposure leads to allergen sensitization in susceptible individuals and this might influence allergic rhinitis (AR) phenotype expression. We investigated whether sensitization patterns vary in a country with subtropical and tropical regions and if sensitization patterns relate to AR phenotypes or age. METHODS: In a national, cross-sectional study AR patients (2-70 y) seen by allergists underwent blinded skin prick testing with a panel of 18 allergens and completed a validated questionnaire on AR phenotypes. RESULTS: 628 patients were recruited. The major sensitizing allergen was house dust mite (HDM) (56%), followed by Bermuda grass (26%), ash (24%), oak (23%) and mesquite (21%) pollen, cat (22%) and cockroach (21%). Patients living in the tropical region were almost exclusively sensitized to HDM (87%). In the central agricultural zones sensitization is primarily to grass and tree pollen. Nationwide, most study subjects had perennial (82.2%), intermittent (56.5%) and moderate-severe (84.7%) AR. Sensitization was not related to the intermittent-persistent AR classification or to AR severity; seasonal AR was associated with tree (p < 0.05) and grass pollen sensitization (p < 0.01). HDM sensitization was more frequent in children (0-11 y) and adolescents (12-17 y) (subtropical region: p < 0.0005; tropical region p < 0.05), but pollen sensitization becomes more important in the adult patients visiting allergists (Adults vs children + adolescents for tree pollen: p < 0.0001, weeds: p < 0.0005). CONCLUSIONS: In a country with (sub)tropical climate zones SPT sensitization patterns varied according to climatological zones; they were different from those found in Europe, HDM sensitization far outweighing pollen allergies and Bermuda grass and Ash pollen being the main grass and tree allergens, respectively. Pollen sensitization was related to SAR, but no relation between sensitization and intermittent-persistent AR or AR severity could be detected. Sensitization patterns vary with age (child HDM, adult pollen). Clinical implications of our findings are dual: only a few allergens -some region specific- cover the majority of sensitizations in (sub)tropical climate zones. This is of major importance for allergen manufacturers and immunotherapy planning. Secondly, patient selection in clinical trials should be based on the intermittent-persistent and severity classifications, rather than on the seasonal-perennial AR subtypes, especially when conducted in (sub)tropical countries.
RESUMO
BACKGROUND: allergic rhinitis is the most common allergic disease worldwide. Aeroallergens are compromise in its presentation and its prevalence varies in different parts of the world. Aeroallergen sensitization in the Guadalajara metropolitan area is not yet documented. OBJECTIVE: to determine by means of skin prick test the sensitization prevalence to aeroallergens in patients with allergic rhinitis. PATIENTS AND METHODS: We retrospective evaluated the results of skin prick test to different aeroallergens and their prevalence by age group in patients with allergic rhinitis referred to our allergy department. RESULTS: the complete data of 965 subjects were available, 78% of these had positive skin prick tests, the age range of the patients was 16 to 78 years, 74.9% of which were women; 9% were sensitized to one allergen and 11.5% had more than 15 positive skin prick test. The most frequent interior allergens were house dust mites and outdoor allergens Quercus sp and Fraxinus sp. Males showed the highest reaction frequency to aeroallergens. The age range from 21 to 40 years presented the highest frequency of positive skin prick test. CONCLUSION: our data demonstrate that house dust mites followed by tree pollens are the most frequent aeroallergens in patient with allergic rhinitis. Positive skin prick test frequency was age associated.